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Cannabis and depression: An integrative data analysis of four Australasian cohorts

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Background: This study presents an integrative data analysis of the association between frequency of cannabis use and severity of depressive symptoms using data from four Australasian cohort studies. The integrated data comprised observations on over 6900 individuals studied on up to seven occasions between adolescence and mature adulthood. Methods: Repeated measures data on frequency of cannabis use (not used/<monthly/≥monthly/≥weekly) and concurrently assessed depression scores were pooled over the four cohorts. Regression models were fitted to estimate the strength of association between cannabis use and depression. Fixed effects regression methods were used to control for confounding by non-observed fixed factors. Results: Increasing frequency of cannabis use was associated with increasing depressive symptoms (p<0.001). In the pooled data weekly users of cannabis had depression scores that were 0.32 (95%CI 0.27-0.37) SD higher than non-users. The association was reduced but remained significant (p<0.001) upon adjustment for confounding. After adjustment depression scores for weekly users were 0.24 (95%CI 0.18-0.30) SD higher than non-users. The adjusted associations were similar across cohorts. There was a weak age×cannabis use interaction (p<0.05) suggesting that the association was strongest in adolescence. Attempts to further test the direction of causality using SEM methods proved equivocal. Conclusions: More frequent cannabis use was associated with modest increases in rates of depressive symptoms. This association was stronger in adolescence and declined thereafter. However, it was not possible from the available data to draw a definitive conclusion as to the likely direction of causality between cannabis use and depression.

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... It is the most widely used illicit psychoactive substance in the world 3 , and the potential medicinal and therapeutic benefits of cannabis and its main active ingredients tetrahydrocannabinol (THC) and cannabidiol (CBD) are gaining interest [4][5][6] . There is strong evidence to suggest that the heavy and prolonged use of cannabis may be associated with increased risk of adverse outcomes in a number of areas, including mental health (psychosis 7-9 , schizophrenia 10,11 , depression 12,13 ) and illicit drug abuse 14 . ...
... The Christchurch Health and Development Study includes individuals who have been studied on 24 occasions from birth to the age of 40 (n = 987 at age 30, with blood collected at approximately age 28). In the early 1990s, research began into the initiation and consequences of cannabis use amongst CHDS participants; cannabis use was assessed prospectively over the period up to the collection of DNA [11][12][13][14][48][49][50][51][52][53][54] . A subset of n = 96 participants for whom a blood sample was available are included in the current study. ...
... This is consistent with the literature which raises clinical concerns around cardiac complications potentially associated with cannabis use [100][101][102][103] . The enrichment of genes associated with neural signalling pathways is also consistent with the literature, including previous analyses of the CHDS cohort, which report associations between cannabis exposure and brain related biology such as mood disorders 7,12,48,49,[51][52][53][54]104,105 . Our study was limited by sample size, achieving~10% power at P = 10 −7 to detect the largest standardised effect size found. ...
Article
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Cannabis use is of increasing public health interest globally. Here we examined the effect of heavy cannabis use, with and without tobacco, on genome-wide DNA methylation in a longitudinal birth cohort (Christchurch Health and Development Study, CHDS). A total of 48 heavy cannabis users were selected from the CHDS cohort, on the basis of their adult exposure to cannabis and tobacco, and DNA methylation assessed from whole blood samples, collected at approximately age 28. Methylation in heavy cannabis users was assessed, relative to non-users (n = 48 controls) via the Illumina Infinium® MethylationEPIC BeadChip. We found the most differentially methylated sites in cannabis with tobacco users were in the AHRR and F2RL3 genes, replicating previous studies on the effects of tobacco. Cannabis-only users had no evidence of differential methylation in these genes, or at any other loci at the epigenome-wide significance level (P < 10⁻⁷). However, there were 521 sites differentially methylated at P < 0.001 which were enriched for genes involved in neuronal signalling (glutamatergic synapse and long-term potentiation) and cardiomyopathy. Further, the most differentially methylated loci were associated with genes with reported roles in brain function (e.g. TMEM190, MUC3L, CDC20 and SP9). We conclude that the effects of cannabis use on the mature human blood methylome differ from, and are less pronounced than, the effects of tobacco use, and that larger sample sizes are required to investigate this further.
... Multiple studies found evidence that early-onset cannabis use or frequent cannabis use are significant risk factors for symptoms of depression in adulthood. 21,57,[69][70][71][72][73][74][75][76][77] In 1 publication, cannabis use increased the risk for depressive symptoms if the use began in adolescence, but not in later life. 72 Similar findings were obtained by another study that assessed cannabis use and psychiatric symptoms at ages 15, 18, and 26 in a community sample (n = 759). ...
... 70 Concerning the effects of frequent cannabis use, in a major publication collapsing data from 4 separate cohort studies, data from all 4 studies demonstrated a dosedependent relationship between cannabis use and subsequent increases in depressive symptomology. 73 Similarly, in a prospective design following a sample of adults (N = 3881) for 3 years, results indicated that baseline cannabis use predicted a future diagnosis of MDD in a dose-dependent manner. 74 The association between cannabis use and depressive symptomology is stronger in individuals with CUD than in non-dependant users. ...
... Of the studies we reviewed, cannabis use appeared to increase the risk of developing depressive symptoms, although the strength of this association varied considerably between reports. 21,53,57,[69][70][71][72][73][75][76][77]84,97,98 Interestingly, a recently published report shows that 28 days of cannabis abstinence in people with major depression led to significant reductions in depression, anxiety, and anhedonic symptoms. 99 Are certain populations at greater risk for developing cannabis-related psychiatric symptoms? ...
Article
The association between cannabis use and psychiatric disorders has been extensively investigated, but the effect of cannabis use on the induction and persistence of psychiatric symptoms in healthy individuals is less clear. We determines whether cannabis contributes to the induction and persistence of psychotic, depressive, or (hypo)manic symptoms in healthy individuals. We identified populations that are most susceptible to these effects, in addition to cannabis use behaviors that increase the risk of developing cannabis-related psychiatric symptoms. A systematic review was performed using the PubMed, Medline, and PsychInfo databases. We conducted our search using the following terms: (“cannabis” OR “tetrahydrocannabinol” OR “cannabidiol” OR “marijuana” OR “cannabinoid” OR “nabilone” OR “dronabinol” OR “nabiximols”) AND (“psycho∗” OR “mood disorder” OR “depress∗” OR “mania” OR “manic” OR “hypomania”). Experimental and observational studies published from January, 1987 to March, 2021 were considered in our analysis. We assessed evidence from 47 studies, including 6 experimental studies, 28 cohort studies, and 13 cross-sectional studies. Adverse effects of cannabis or cannabinoids were found in 30/32 (93.8%) of studies reporting psychotic symptoms, 13/18 studies (72.2%) reporting depressive symptoms, and 4/4 studies (100%) reporting (hypo)manic symptoms. Cannabis use robustly increased the risk of developing psychotic and (hypo)manic symptoms, but the effects of cannabis use on depression were mixed. Risk of developing symptoms was influenced by the age of onset, tetrahydrocannabinol potency, and frequency of cannabis use. Cannabis use increases the risk of developing and maintaining psychotic and (hypo)manic symptoms, with mixed effects for depressive symptoms, in healthy individuals. These effects occur in a dose-dependent manner and are dependent upon THC potency. More research is necessary to understand the effects of cannabis, particularly on the induction and persistence of depressive and (hypo)manic symptoms. L’association entre la consommation de cannabis et les troubles psychiatriques a été largement étudiée, mais l’effet de la consommation de cannabis sur l’induction et la persistance des symptômes psychiatriques chez les individus en bonne santé est moins clair. Nous avons déterminé si le cannabis contribue à l’induction et à la persistance de symptômes psychotiques, dépressifs ou (hypo)maniaques chez des individus en bonne santé. Nous avons identifié les populations les plus sensibles à ces effets, en plus des comportements de consommation de cannabis qui augmentent le risque de développer des symptômes psychiatriques liés au cannabis. Un examen systématique a été réalisé à l’aide des bases de données PubMed, Medline et PsychInfo. Nous avons effectué notre recherche en utilisant les termes suivants: (“cannabis” OU “tétrahydrocannabinol” OU “cannabidiol” OU “marijuana” OU “cannabinoïde” OU “nabilone” OU “dronabinol” OU “nabiximols”) ET (“psycho∗” OU “trouble de l’humeur » OU « déprimé∗ » OU « manie » OU « maniaque » OU « hypomanie »).” Les études expérimentales et observationnelles publiées de janvier 1987 à mars 2021 ont été prises en compte dans notre analyse. Nous avons évalué les résultats de 47 études, dont 6 études expérimentales, 28 études de cohorte et 13 études transversales. Des effets indésirables du cannabis ou des cannabinoïdes ont été trouvés dans 30/32 (93,8%) des études rapportant des symptômes psychotiques, 13/18 études (72,2%) rapportant des symptômes dépressifs et 4/4 études (100%) rapportant des symptômes (hypo)maniaques. La consommation de cannabis augmentait fortement le risque de développer des symptômes psychotiques et (hypo)maniaques, mais les effets de la consommation de cannabis sur la dépression étaient mitigés. Le risque de développer des symptômes était influencé par l’âge d’apparition, la puissance du tétrahydrocannabinol (THC) et la fréquence de consommation de cannabis. La consommation de cannabis augmente le risque de développer et de maintenir des symptômes psychotiques et (hypo)maniaques, avec des effets mitigés pour les symptômes dépressifs, chez les individus en bonne santé. Ces effets se produisent de manière proportionnelle à la dose et dépendent de la puissance du THC. Des recherches supplémentaires sont nécessaires pour comprendre ces effets du cannabis, en particulier sur l’induction et la persistance des symptômes dépressifs et (hypo)maniaques.
... Medicinal cannabis is currently approved for most of the aforementioned indications in Australia, New Zealand, Canada, some states in USA, and a number of countries throughout Europe, Asia and South America. Conversely, use of certain chemovars of C. sativa L. as a whole plant product may exacerbate symptoms of mental health disorders in some people, particularly high THC, low CBD strains (15)(16)(17). It can also increase the likelihood of developing mood or psychiatric illnesses (18)(19)(20). ...
... αpinene and β-pinene are the prominent terpenes in many C. sativa L. chemovars (26,(51)(52)(53). For example, one study reported average α-pinene and β-pinene concentrations of 15 (54). Another study reported high levels of α-pinene in Lemon Skunk and CBD Skunk Haze, while β-pinene was dominant in Purple Kush (25). ...
Article
Full-text available
“Medicinal cannabis” is defined as the use of cannabis-based products for the treatment of an illness. Investigations of cannabis compounds in psychiatric and neurological illnesses primarily focus on the major cannabinoids, cannabidiol (CBD) and Δ ⁹ -tetrahydrocannabinol (Δ ⁹ -THC), which are hypothesised to benefit multiple illnesses manifesting cognitive impairment, neurodegeneration and neuro-inflammation, as well as chronic pain, epilepsy and post-traumatic stress disorder, respectively. The cannabis plant contains >500 compounds, including terpenes responsible for the flavour and fragrance profiles of plants. Recently, research has begun providing evidence on the potential use of certain plant-derived terpenes in modern medicine, demonstrating anti-oxidant, anti-inflammatory, and neuroprotective effects of these compounds. This review examined the effects of two key terpenes, pinene and linalool, on parameters relevant to neurological and psychiatric disorders, highlighting gaps in the literature and recommendations for future research into terpene therapeutics. Overall, evidence is mostly limited to preclinical studies and well-designed clinical trials are lacking. Nevertheless, existing data suggests that pinene and linalool are relevant candidates for further investigation as novel medicines for illnesses, including stroke, ischemia, inflammatory and neuropathic pain (including migraine), cognitive impairment (relevant to Alzheimer's disease and ageing), insomnia, anxiety, and depression. Linalool and pinene influence multiple neurotransmitter, inflammatory and neurotrophic signals as well as behaviour, demonstrating psycho-activity (albeit non-intoxicating). Optimising the phytochemical profile of cannabis chemovars to yield therapeutic levels of beneficial terpenes and cannabinoids, such as linalool, pinene and CBD, could present a unique opportunity to discover novel medicines to treat psychiatric and neurological illnesses; however, further research is needed.
... Cannabis is one of the most commonly used psychoactive drugs [1], and depression is the second leading cause of disability [2] world-wide. Given the known comorbidity between these traits [3][4][5][6][7], understanding the nature of their relationship is highly relevant from a public health perspective. This is particularly true in the context of changing legislation and public perceptions of the risks of using cannabis [8]. ...
... In this study we used data from UK Biobank [28,29] in addition to summary statistics available from genome-wide analyses by the PGC-MDD working group [14] and the 2016 International Cannabis Consortium [30] (ICC) to estimate the relationship between cannabis use, depression and self-harm. While the ICC consider all individuals who have ever tried cannabis use, cross-sectional evidence suggests that more frequent cannabis use is more strongly associated with depression [7]. The phenotypic detail available in UK Biobank allowed us to investigate the risks associated with initial cannabis use (using cannabis 10 times or fewer), as well as continued cannabis use (using cannabis more than 10 times). ...
Article
Background and aims: The use of cannabis has previously been linked to both depression and self-harm; however, the role of genetics in this relationship is unclear. This study aimed to estimate the phenotypic and genetic associations between cannabis use and depression and self-harm. Design: Cross-sectional data collected through UK Biobank were used to test the phenotypic association between cannabis use, depression and self-harm. UK Biobank genetic data were then combined with consortia genome-wide association study summary statistics to further test the genetic relationships between these traits using LD score regression, polygenic risk scoring and Mendelian randomization methods. Setting: United Kingdom, with additional international consortia data. Participants: A total of 126 291 British adults aged between 40 and 70 years, recruited into UK Biobank. Measurements: Phenotypic outcomes were life-time history of cannabis use (including initial and continued cannabis use), depression (including single-episode and recurrent depression) and self-harm. Genome-wide genetic data were used and assessment centre, batch and the first six principal components were included as key covariates when handling genetic data. Findings: In UK Biobank, cannabis use is associated with an increased likelihood of depression [odds ratio (OR) = 1.64, 95% confidence interval (CI) = 1.59-1.70] and self-harm (OR = 2.85, 95% CI = 2.69-3.01). The strength of this phenotypic association is stronger when more severe trait definitions of cannabis use and depression are considered. Using consortia genome-wide summary statistics, significant genetic correlations are seen between cannabis use and depression [rg = 0.289, standard error (SE) = 0.036]. Polygenic risk scores for cannabis use and depression explain a small but significant proportion of variance in cannabis use, depression and self-harm within a UK Biobank target sample. However, two-sample Mendelian randomization analyses were not significant. Conclusions: Cannabis use appeared to be both phenotypically and genetically associated with depression and self-harm. Limitations in statistical power mean that conclusions could not be made on the direction of causality between these traits.
... Long-term use is four times more likely to give rise to depression [87]. Horwood et al., using data from four Australian cohort studies, have provided evidence for an association between the increased rate of depressive symptoms and the high frequency of cannabis use; this association was stronger in adolescence [88]. However, they were unable to reach a conclusion regarding the causality between depression and cannabis use [88]. ...
... Horwood et al., using data from four Australian cohort studies, have provided evidence for an association between the increased rate of depressive symptoms and the high frequency of cannabis use; this association was stronger in adolescence [88]. However, they were unable to reach a conclusion regarding the causality between depression and cannabis use [88]. This association is supported by other reports [74,87,89,90]. ...
... One long-term cohort study, namely, the ''Cambridge Study in Delinquent Development,'' reported that cannabis use, in particular with early initiation, increased the risk of being diagnosed with depression. 55 Studies conducted on Australians, Swiss, and Canadians (Nova Scotians) reported this correlation to be more prominent in chronic cannabis users 56,57 ; yet, with weekly cannabis use being enough to cause a depressive disorder. 56,58 However, as is the case with anxiety, when controlling for confounding factors such as use of other substances, early childhood experience, and education, other studies conducted on Australians, Danes, and Americans (NESARC) reported no clear association between depression and cannabis use. ...
... 55 Studies conducted on Australians, Swiss, and Canadians (Nova Scotians) reported this correlation to be more prominent in chronic cannabis users 56,57 ; yet, with weekly cannabis use being enough to cause a depressive disorder. 56,58 However, as is the case with anxiety, when controlling for confounding factors such as use of other substances, early childhood experience, and education, other studies conducted on Australians, Danes, and Americans (NESARC) reported no clear association between depression and cannabis use. 47,59,60 Cannabis Use and Physical Health Cannabinoids have been linked to a plethora of other side effects related to physical health. ...
Article
Full-text available
The global movement toward legalization of cannabis is resulting in an ever-increasing public perception that cannabis is safe. Cannabis is not the first drug to be available for nonmedical use, nor is it the first to have such an unfounded safety profile. The safety of long-term exposure to phytocannabinoids is misunderstood by, and under reported to, the general public. There is evidence to suggest that long-term use of recreational cannabis may be associated with an increased risk of undesirable side effects. This evidence warrants both appropriate caution from the general public and investment in further research by government and industry sectors that are profiting from the sale of these potent psychoactive agents. There is no doubt that these compounds have medical potential. However, in addition to the medical potential, we must also remain aware of the adverse health effects that are becoming synonymous with recreational cannabis use. This perspective highlights the privileged role that cannabis has as a perceived "safe drug" in society and summarizes some concerning side effects that are becoming associated with regular nonprescribed cannabis use.
... Biological factors include genetic predisposition [34], female gender [10], and neurobiological and hormonal changes [3,9]. Psychosocial factors include low socioeconomic status [11], growing up in the former East Germany [43], critical life events [31], financial worries [1], use of alcohol, drugs, or medication to calm down or enhance performance [6,25,33], and the personality trait neuroticism [15,36]. ...
... On the one hand, emotionally unstable individuals are at increased risk for depressive symptoms [36], on the other hand, depressive states influence the self-assessment of the trait neuroticism [21]. The second strongest correlation is found for the risk factor use of Depressive symptoms in dentistry students -prevalence, risk factors and resilience factors drugs and medications with a high BDI-II sum score, as also found in other works [25,33]. A positive correlation between the prevalence of depressive episodes and the loss of a parent was postulated by Kendler [31] and can only be confirmed to a limited extent in the present study. ...
Article
Introduction: Depression is a leading cause of illness-related disability worldwide. An initial peak of illness is recorded in the young adult years. Among epidemiologic studies of young people, studies of students are primarily available. The mental health of dental students has received little research attention. Many students subjectively report mental health complaints, while studies on this topic are scarce nationally and internationally. This study investigates the mental health of dental students at a medium-sized German university. Methods: A sample of n = 153 dental students completed the Beck Depression Inventory-II to assess depressive symptoms, the NEO Five-Factor Inventory to assess the personality trait neuroticism, and a self-description and study questionnaire that included 8 risk factors, 5 study-related stress factors, and 8 resilience factors described in literature. Results: 41,8 % of the students showed mild (18,3 %), moderate (17,0 %), or severe (6,5 %) depressive symptoms. 5 potential risk factors, 4 potential stress factors and 5 potential resilience factors were identified, which also revealed a cumulative effect: The more risk and stress factors the students indicated, the more depressive symptoms they showed. The opposite was true for the resilience factors. Discussion: The prevalence of depressive symptoms in dental students exceeds that of both the general population and previous national and international studies of depressive symptoms in students. Neuroticism and the use of drugs and medications are potential risk factors, and excessive demands and pressure to perform are study-related stress factors. Emotional support and satisfaction with studies have a protective effect against depressive symptoms. Conclusion: The results are of great significance not only because of the current psychological strain on dental students but also regarding their role in the health care system. Students should be informed and sensitized regarding this issue. Specific education on depression is useful to destigmatize the issue and raise awareness of the condition. University programs can also contribute to an early recognition and prevention of depressive symptoms to protect the mental health of potential future dentists.
... Our second goal was to explore the roles that depression, other substance use, and personality play in the putative associations between cannabis use and motivation. Few studies examining "amotivational syndrome" have measured or controlled for symptoms of depression, despite the fact that reduced motivation is a symptom of depression (Center for Substance Abuse Treatment, 2008), and that depression is positively related to cannabis use (Gobbi et al., 2019;Horwood et al., 2012;Lev-Ran et al., 2014;Sexton, Cuttler, Finnell, & Mischley, 2016). While the direction of this relationship remains unclear and may be bidirectional, it is possible that the link between cannabis use and amotivation is largely spurious and driven by cannabis-related elevations in depression. ...
Article
Background: Cannabis use is widely perceived to produce an “amotivational syndrome” characterized by reduced desire to work or compete, passivity, and lower achievement orientation. The notion that cannabis diminishes motivation has been perpetuated in popular culture, despite the equivocal results of past research. Moreover, previous literature has largely failed to consider the potentially confounding influences of depression, other substance use, and personality, despite known relationships between these variables and cannabis use. Purpose: The purpose of this study was to elucidate the nature of the relationships between specific aspects of motivation and cannabis use/misuse. Moreover, we sought to determine whether depression, alcohol and other substance use, and/or personality could account for these relationships. Method: A total of 1,168 participants completed a survey comprising self-report measures of motivation (self-efficacy, apathy, goal orientation, reward-sensitivity, and behavioral inhibition/approach systems) and cannabis use/misuse (cannabis use status, cannabis use frequency, quantity, age of onset of cannabis use, symptoms of cannabis use disorder, problematic cannabis use). Results: The results revealed small (r < .30) but significant correlations between various aspects of cannabis use and motivation, which were largely accounted for by cannabis-related differences in depression, alcohol and other substance use, and personality. However, relationships between cannabis misuse and apathy remained statistically significant after controlling for confounds, indicating that individuals who misuse cannabis may demonstrate higher levels of apathy specifically. Conclusion: Collectively, these results suggest that differences in depression, substance use, and personality between cannabis users and non-users largely explain differences in motivation between these groups.
... . The analyses are often carried out with a recognition of study differences by either including study dummies (dummy coded variables to draw comparisons between studies), multi-group, or multilevel models (depending on the number of studies combined) to statistically test for the invariance of model parameters. Initially IDA was conducted in longitudinal studies given their expense and smaller samples (e.g., McArdle, et al., 2009); however, IDA is currently being applied in many disciplines and types of studies (e.g., Adams, et al., 2015;Horwood et al., 2012;Luningham, et al., 2019;McGrath, Leighton, Ene, DiStefano, & Monrad, in press). ...
Article
Integrative data analysis (IDA) involves obtaining multiple datasets, scaling the data to a common metric, and jointly analyzing the data. The first step in IDA is to scale the multisample item-level data to a common metric, which is often done with multiple group item response models (MGM). With invariance constraints tested and imposed, the estimated latent variable scores from the MGM serve as an observed variable in subsequent analyses. This approach was used with empirical multiple group data and different latent variable estimates were obtained for individuals with the same response pattern from different studies. A Monte Carlo simulation study was then conducted to compare the accuracy of latent variable estimates from the MGM, a single-group item response model, and an MGM where group differences were ignored. Results suggest that these alternative approaches led to consistent and equally accurate latent variable estimates. Implications for IDA are discussed.
... Exploring the inverse notion that MDD may lead to the onset of cannabis use, particularly at younger ages, yield conflicting results. On one hand, integrated finding from four Australian cohorts has indicated a moderate positive association between baseline frequent cannabis use and depression scores at a follow-up (Horwood et al. 2012). In this study, the association between cannabis use frequency and future depression has been found to decrease with age, peaking at age 15 and declining at age 30. ...
Chapter
There is a growing body of evidence pointing to the co-occurrence of cannabis use and depression. There is also some evidence that the use of cannabis may lead to the onset of depression; however, strong evidence points to the inverse association; i.e. that depression may lead to the onset or increase in cannabis use frequency. Observational and epidemiological studies have not indicated a positive long-term effect of cannabis use on the course and outcome of depression. The association between cannabis use and depression may be stronger among men during adolescence and emerging adulthood and stronger in women during midlife. There is an indication for potential genetic correlation contributing to the comorbidity of cannabis dependence and major depression, namely that serotonin (5-HT) may mediate such association and there is also evidence for specific risk alleles for cannabis addiction. There is preclinical evidence that alteration in the endocannabinoid system could potentially benefit patients suffering from depression. However, the issue of using cannabis as an anti-depressant is at an early stage of examination and there is little evidence to support it. Finally, there has been little support to the notion that selective serotonin reuptake inhibitors (SSRIs) may be effective in decreasing depressive symptoms or rates of substance use in adolescents treated for depression and a co-occurring substance use disorder. In conclusion, despite methodological limitations, research in the past decades has broadened our knowledge on the association between cannabis use and depression from epidemiological, neurological, genetic, and pharmacological perspectives.
... The relation between cannabis use and other more common psychiatric disorders such as anxiety and depression is less consistent. However, a 2012 report from the Christchurch Study along with three other Australasian cohort studies showed that increasing amounts of cannabis use were associated with increasing depressive symptoms and that the association was strongest among adolescents (Horwood et al. 2012). The authors noted that they were unable to determine whether the direction of the relationship was likely to be from cannabis use to depression or whether depression led to cannabis use. ...
Article
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The majority of New Zealanders (approximately 80%) born in the 1970s report using cannabis at least once, despite its illegal status. Four-10% of past-year users were at risk of developing a cannabis dependence syndrome that impaired psychological, social and/or occupational functioning. There were negative psychiatric consequences for a subset of the population who began using cannabis in early/mid-adolescence, particularly in terms of developing psychosis (the risk appeared to be highest for those with a genetic predisposition), and to a lesser degree for depression. There was a consistent dose–response relation between increasing levels of, and/or persistence of cannabis use and a range of deleterious health outcomes including loss of cognitive capacity, increased respiratory symptoms and impaired lung function, periodontal disease, compromised educational achievement and employment history, as well as a host of negative social outcomes (e.g. criminal convictions, relationship difficulties, driving impairment). No discernable impacts upon cardiovascular function were observed. The majority of cannabis users did so with little or no harm. In contrast, a non-trivial minority of the population (approximately 5%–10%) were at heightened risk because they: (i) used cannabis on more days than not; (ii) had become cannabis dependent; or (iii) began using cannabis during mid-adolescence and persisted well into adulthood. Implications are discussed with respect to the 2020 referendum.
... The family environment has previously been identified as an important predictor of early onset use of other substances, such as alcohol, in adolescence [23]. Family-related factors generally play a more important role in shaping health-related behaviour in childhood, while peer-related factors become relatively more influential throughout adolescence [28]. In contrast, with respect to family factors, only family history of antisocial behaviour was a statistically significant predictor of late adolescent onset occasional cannabis use, though cumulative risks within the family did also predict membership of this group. ...
Article
Introduction and Aims This study prospectively investigates behavioural and social antecedents of different patterns of adolescent cannabis use, specifically, early adolescent onset cannabis use and late onset occasional use. Design and Methods The sample comprised 852 adolescents (53% female) drawn from the Australian arm of the International Youth Development Study. Data were collected via self‐report surveys. Risk and protective factors from a modified version of the Communities That Care youth survey were measured in fifth grade (mean [M] = 10.9 years, SD = 0.4). Frequency of cannabis use was measured at six time‐points throughout adolescence (ages 12–19 years). Results Early adolescent onset cannabis use (10.7% of the sample [n = 91]) was predicted by childhood family‐related factors including poor family management, family history of antisocial behaviour and attachment to parents. Cigarette use and drinking until drunk were the strongest predictors of early adolescent onset cannabis use. Cumulative risks associated with community, family, peer/individual environments and early substance use (cigarettes, alcohol) in childhood were predictive of early adolescent onset cannabis use (e.g. relative risk ratio = 2.64; 95% confidence interval 1.40–4.97 for early substance use). Family and early substance use‐related cumulative risks were predictive of late adolescent onset occasional cannabis use (n = 231; 27%). Cumulative early substance use risk was the strongest independent predictor of both early adolescent onset and late adolescent onset occasional cannabis use. Discussion and Conclusions Primary prevention efforts should focus on reducing exposure and access to licit substances during late childhood and delaying the onset of use. Prevention and intervention targeted toward the family environment also appears likely to be important in the prevention of early adolescent onset cannabis use.
... In a 2007 systematic review on cannabis use and mental health outcomes published in the Lancet which included New Zealand longitudinal study findings, the authors argued that although it was difficult to answer with certainty whether cannabis caused these particular mental health conditions; that there was enough evidence to justify public education campaigns to inform people of the possible risks (Moore et al. 2007). For example, a 2012 research paper that reported data integrated from four Australasian longitudinal studies in different geographical locations found that increasing amounts of cannabis use was associated with increasing depressive symptoms and that the association was strongest in adolescents (Horwood et al. 2012). The authors noted, however, that they were unable to determine whether the direction of the relationship was likely to be from cannabis use to depression or whether depression led to cannabis use. ...
Article
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For Māori, the Indigenous peoples of Aotearoa New Zealand, cannabis use and resulting interactions with the justice system are shaped by structural determinants of inequity including the country’s colonial history and the ongoing consequences and impacts of colonisation, institutional racism and poverty. Māori have higher rates of cannabis use than non-Māori and are more likely to be convicted on cannabis charges, even accounting for higher rates of use. In 2020, New Zealanders will vote either ‘yes’ or ‘no’ to legalising personal cannabis use. Ensuring Māori rights to health equity and parity of outcomes is a government responsibility under Te Tiriti o Waitangi (the Treaty of Waitangi). This paper synthesises information from previous research studies, with a focus on lifecourse research, to describe how cannabis may affect the health and wellbeing of Māori youth. Māori are a proportionately youthful and growing population. Based on current evidence we make recommendations to support the wellbeing of Māori youth and reduce inequities across the lifecourse. These include treating regular cannabis use and dependence as a health not a criminal issue; age restrictions for purchasing cannabis; equal partnership with Māori to support effective policy, regulation and services; and ongoing monitoring of cannabis use by youth.
... The prevalence of cannabis use is more common among adults with mental disorders, including depression, compared to those without mental disorders (Lev-Ran et al., 2013;Shi, 2014;Smith et al., 2014;Weinberger et al., 2019) and youth with depression report greater negative consequences of cannabis use than youth without depression (Pedersen et al., 2015). Heavy cannabis use is associated with increased incidence and prevalence of depression (Agrawal et al., 2017;Degenhardt et al., 2003;Gobbi et al., 2019;Halladay et al., 2019;Lev-Ran et al., 2014; see also Degenhardt et al., 2013) and a large study of cohort samples in Australia and New Zealand found that the relationship between cannabis use and depression symptoms was stronger among adolescents than older age groups (Horwood et al., 2012). ...
Article
Background: Cannabis use has significant negative consequences for youth. Depression is associated with greater cannabis use among adults but less is known about cannabis use and depression among youth. This study investigated whether depression is associated with increased cannabis use among youth in the United States (US), overall and by demographics, and examined trends in cannabis use by depression status among youth from 2004 to 2016. Methods: Data were from the 2004-2016 National Survey on Drug Use and Health (NSDUH), annual cross-sectional national samples of US persons 12 and older. The analytic sample included respondents aged 12-17 (total combined n=204,102). First, the prevalence of past-month cannabis use by past-year depression status among youth was examined, overall and by demographic subgroups, using pooled data from 2004-2016. Next, linear time trends of past-month cannabis use were assessed by depression status from 2004 to 2016 using logistic regression models with continuous year as the predictor. Models with year-by-depression status interaction terms assessed differential time trends for those with and without depression. Results: From 2004-2016, cannabis use increased both among youth with and without depression. Cannabis use increased significantly more rapidly among youth with (8.45% to 11.65%), compared to without, depression (4.28% to 4.71%). Youth with depression were more than twice as likely to report cannabis use (12.86% versus 6.40%), relative to those without depression. Conclusions: Cannabis use was more than twice as common and increased more rapidly from 2004 to 2016 among youth with depression compared to youth without depression.
... Evidence exists supporting the therapeutic potential of cannabis and cannabis-based medications for relieving spasticity and chronic pain in patients with multiple sclerosis and other neurological disorders (Koppel et al. 2014), improving poor appetite (Abrams et al. 2003) and neuropathy ) in HIV patients, and decreasing nausea and vomiting in cancer patients during chemotherapy treatment (Machado Rocha et al. 2008). Conversely, known side effects of cannabis use include cognitive impairment (Meier et al. 2012), anxiety and panic reactions (Dannon et al. 2004), mood disturbances (Patton et al. 2002;Horwood et al. 2012), and increased risk of developing psychotic disorders (Andreasson et al. 1987;Zammit et al. 2002). Patient cohort studies have highlighted that the health outcomes of chronic cannabis consumption vary depending on the user's past medical history, the chemical composition of the drug, and the uptake pathway (Pacher et al. 2008;Ramaekers et al. 2009). ...
Article
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Objective: The rapid increase of cannabis consumption reinforces the need to elucidate the health hazards of this practice. The presence of fine particulate matter in cannabis smoke and vapor poses a major concern, as it may contribute to cardiopulmonary disease. To facilitate the assessment of risks associated with cannabis inhalation, we developed and characterized a method for exposing mice to cannabis in a way that mimics the delivery of the drug to the airways of smokers. Materials and Methods: Cannabis (10.3% THC, 0.05% CBD) was vaporized to generate aerosols with a reproducible particle profile. Aerosols were acutely delivered to male, adult C57BL/6 mice via a nose-only exposure system. Serum THC levels were measured for increasing cannabis doses. Blood pressure and heart rate were recorded at baseline and following exposure. Behavioral response to cannabis inhalation in the open field was documented. Awake neurological activity upon cannabis exposure was monitored using BOLD fMRI. Results and Discussion: Cannabis aerosols contained particles with count median diameter of 243 ± 39 nm and geometric standard deviation of 1.56 ± 0.06. Blood serum THC levels increased linearly with aerosolized mass and peaked at 136 ± 5 ng/mL. Cannabis inhalation decreased heart rate and blood pressure but promoted anxiety-like behavior. Observed differences in BOLD activation volumes linked cannabis to increased awareness to sensory stimuli and reduced behavioral arousal. Conclusions: Quantified physiological, behavioral, and neurological responses served as validation for our mouse model of cannabis inhalation. Animal models of aerosol exposure will be instrumental for uncovering the health outcomes of chronic cannabis use.
... On the other hand, it has been shown that cannabis abuse increases the risk of experiencing depression and anxiety in the future [20], where several studies that have been conducted have reported a strong relationship between cannabis, anxiety and mood disorders [21][22][23]. With regard to depression and cannabis users, it has been found that this relationship varies with age, where a depressive disorder is stronger in mid-adolescence and weaker in mature adulthood [24]. ...
Article
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(1) Background: Numerous studies state that the abuse of psychoactive substances produces cognitive, emotional and behavioral disorders. The aim of this study is to analyze the relationship between the consumption of different psychoactive substances with cognitive performance and depression. (2) Methods: The sample was composed of 254 individuals (M = 41.81; SD = 10.74, from 18 to 69; 76% male) who received psychological treatment related to the use of substances. Participants were classified according to the main substance consumed: alcohol (42.9%), cannabis (20.5%), cocaine (15.4%), heroin (13%) and benzodiazepines (8.3%). The Montreal Cognitive Assessment and the Beck’s Depression Inventory were administrated. (3) The results indicated no statistically significant differences between levels of depression depending on the substance consumed. Regarding cognitive impairment, it was found that cocaine consumers have the worst level of cognitive impairment, while cannabis consumers have the best level of cognitive functioning. Finally, it was found that participants with severe depression have higher cognitive impairment than those who were diagnosed with moderate depression. (4) Conclusions: Given the high prevalence of depression and cognitive impairment with the abuse of psychoactive substances, early treatment is recommended to avoid a higher cognitive and emotional affectation.
... Second, there appears to be a dose-response relationship between risk of internalizing disorder symptoms and odds of cannabis use. This is similar to other research findings that observe continued cannabis use in adolescence is associated with increasing depressive symptoms (Horwood et al., 2012) and risk of anxiety disorder . Moreover, use during these formative years has been tied to increased rates of subsequent illicit drug use and use disorders (Lynskey et al., 2012), as well as suicidal ideation and personality disorders (Copeland et al., 2013). ...
Article
Background Adolescent cannabis use is perceived as a risky behavior, has been linked with many negative health outcomes, and is increasingly being connected with stigma. Methods The purpose of this study is to investigate how cannabis use is associated with potentially stigmatizing markers of identity among adolescents two waves of a repeat cross-sectional survey (2015 N=12,110; 2017 N = 15,191) of high schools students in seven Canadian provinces. Students were asked about ever use of cannabis, as well as “stigma markers”, including their current living arrangement, mother’s education, and ethnicity. Multivariable logistic regression models were used to examine associations between cannabis use and stigma markers. Results After adjusting models for grade, gender and province of residence, students who did not live with their mothers had higher odds of cannabis use relative to students living with their mothers [OR = 1.94, 95% CI 1.62–2.31]. Low maternal education was also significantly associated with cannabis use, as was ethnicity (students who identified as Indigenous had 3.38 (95% CI 2.29–4.99) times higher odds of using cannabis compared to students who identified as “white” in 2017). Findings related to attending school in a rural (vs. urban) area (2015 OR = 1.33 95% CI 0.99–1.78; 2017 OR = 1.44 95% CI 0.9–-2.15) and low SES (2015 OR = 0.99, 95% 0.98–1.00; 2017 OR = 1.00, 95% CI 0.98–1.01) were more marginal. Conclusions Future research should explore cannabis initiation experiences among vulnerable groups to better understand potential stigma triggers.
... Withinperson change models determine whether, within an individual, changes in parenting and peer factors predict subsequent changes in substance use. Within-person change models are underutilized in research on adolescent substance use: we are aware of few studies that use fixed effects to examine the relationship between changes in individual-level risk factors and changes in adolescent substance use [10,11,31,[43][44][45]. In conjunction with existing evidence from traditional approaches, if changes in parenting and peer factors predict changes in substance use, we can be more confident that these effects are causal and not spurious. ...
Article
Full-text available
Purpose: There are well-established associations between parental/peer relationships and adolescent substance use, but few longitudinal studies have examined whether adolescents change their substance use in response to changes in their parents' behavior or peer networks. We employ a within-person change approach to address two key questions: Are changes in parenting and peer factors associated with changes in adolescent marijuana and alcohol use? Are there sensitive periods when changes in parenting and peer factors are more strongly associated with changes in adolescent marijuana and alcohol use? Methods: We analyzed longitudinal data collected annually on 503 boys, ages 13-19, recruited from Pittsburgh public schools. Questionnaires regarding parental supervision, negative parenting practices, parental stress, physical punishment, peer delinquency, and peer drug use were administered to adolescents and their caretakers. Alcohol and marijuana use were assessed by a substance use scale adapted from the National Youth Survey. Results: Reductions in parental supervision and increases in peer drug use and peer delinquency were associated with increases in marijuana frequency, alcohol frequency, and alcohol quantity. Increases in parental stress were associated with increases in marijuana and alcohol frequency. The magnitudes of these relationships were strongest at ages 14-15 and systematically decreased across adolescence. These associations were not due to unmeasured stable confounders or measured time-varying confounders. Conclusions: Reducing or mitigating changes in parenting and peer risk factors in early adolescence may be particularly important for preventing substance use problems as adolescents transition into young adulthood.
... Second, there appears to be a dose-response relationship between risk of internalizing disorder symptoms and odds of cannabis use. This is similar to other research findings that observe continued cannabis use in adolescence is associated with increasing depressive symptoms (Horwood et al., 2012) and risk of anxiety disorder . Moreover, use during these formative years has been tied to increased rates of subsequent illicit drug use and use disorders (Lynskey et al., 2012), as well as suicidal ideation and personality disorders (Copeland et al., 2013). ...
Article
Full-text available
Background/Aims. Adolescents who identify as nonbinary gender or as not heterosexual report higher levels of mental illness than their counterparts. Cannabis use is a commonly employed strategy to cope with mental illness symptoms among adolescents; however, cannabis use can have many deleterious health consequences for youth. Within the frame of minority stress theory, this study investigates the relationships between gender identity and sexual orientation, internalizing disorder symptoms, and cannabis use among adolescents. Method. A national cross-sectional survey of a generalizable sample of high school students in Canada from the 2017 wave (N = 15,191) of the Cancer Risk Assessment in Youth Survey was analyzed in spring 2019. Mediation analyses were completed to examine risk of internalizing disorder symptoms as a potential mediator of the association between (1) gender identity and (2) sexual orientation, and cannabis use. Results. Indirect effects in all models show significantly higher levels of reported internalizing disorder symptoms for female (OR = 3.44, 95% CI [2.84, 4.18]) and nonbinary gender (OR = 3.75, 95% CI [2.16, 6.51]) compared with male students. Sexual minority adolescents had higher odds of internalizing disorder risk relative to non–sexual minority adolescents (OR = 3.13, 95% CI [2.63, 3.74]). Students who reported higher rates of internalizing disorder symptoms were more likely to have ever used cannabis. Patterns of partial mediation are also present among all groups. Discussion/Conclusions. Findings can be used to better inform mental health interventions for adolescents. Future study should explore specific mental health stressors of vulnerable adolescent groups with respect to cannabis use as a coping mechanism.
... The cannabinoids (delta-9-tetrahydrocannabinol) and synthetic cannabinoids (K2, spice, or synthetic marijuana) target the endocannabinoid system, which plays a critical role in the development of the central nervous system (Meccariello et al., 2020). The long-term usage of cannabinoids has effects on neurodevelopmental improvement, behavior, reproductivity, and immunological mechanisms (Szutorisz and Hurd, 2016) and is related to psychosis (Pehlivan et al., 2020), mania (Gibbs et al., 2015), depression (Horwood et al., 2012), and SUD (Fergusson et al., 2006). Although earlier reports showed that cannabinoid usage significantly altered histone methylation and acetylation, the number of studies about cannabinoid-mediated epigenome modifications is limited (Dobs and Ali, 2019). ...
Article
This study investigates the relationship between cannabinoid use disorder (CUD) or synthetic cannabinoid use disorder (SCUD) and the global methylation, methylation of NR3C1 gene promotor, and NR3C1 Bcl1 polymorphism, considering clinical parameters. Based on the DSM-5 criteria, 172 SCUD patients’ and 44 CUD patients' diagnoses were confirmed with a positive urine test; 88 healthy volunteers were also included in the study. Global DNA methylation was measured using a 5-methylcytosine (5-mC) DNA ELISA Kit. Methylation-specific PCR was used to identify the methylation of the NR3C1 gene. The analysis of the polymorphism of the NR3C1 gene was evaluated by using the PCR-RFLP. Our results demonstrated that the mean of 5-mC percentages of SCUD patients differed significantly from those of the control group. When comparing NR3C1 gene methylation and clinical parameters due to NR3C1 genotype distribution in patients, the genotype distribution was significantly different between the groups, due to the former's polysubstance abuse. Additionally, there was a significantly positive correlation between the 5-mC percentages of SCUD patients and the reported durations of their disorders. In summary, whereas global DNA methylation may be associated with SCUD, the methylation of the NR3C1 gene and NR3C1 Bcl1 polymorphism were not related to CUD or SCUD.
... Efforts to examine causation in cannabis use and depression using structural equation modelling with large cohorts (e.g. [2]) have also not been able to provide definitive evidence, due to the relatively weak correlations between cannabis use and depression. The inability to determine causality using large data sets and robust methods suggests that answering this particular question may require rather different methods. ...
... Depressed cancer survivors are less likely to adhere to medications and maintain healthy habits, leading to worse prognosis including treatment failures or cancer recurrences (Hansen, 2018;Mausbach et al., 2015;Theofilou & Panagiotaki, 2012). Studies focusing on the noncancer population reported that cannabis users are more likely to have depression than nonusers (Gobbi et al., 2019;Han & Palamar, 2018;Horwood et al., 2012;Lev-Ran et al., 2014;Pacek et al., 2020). In fact, CU is associated with 37% increased risk of depression among adolescence (Gobbi et al., 2019), and heavy CU is associated with 67% increased risk of depression (Lev-Ran et al., 2014). ...
Article
Background Cancer survivors are vulnerable to Cannabis Use (CU) and at increased risk for depression. Yet, the relationship between CU and depression among cancer survivors is unknown. Purpose The purpose of this study was to estimate the prevalence of daily/non-daily CU, investigate the association between CU and depression and evaluate CU reasons and methods of administration among cancer survivors. Method Population-based, nationally representative sample of cancer survivors aged ≥18 (n = 10,799) from 2018 Behavioral Risk Factor Surveillance System Survey was used. Weighted descriptive statistics and multivariate logistic regression were conducted. Findings Overall, 4.2% reported daily and 4.1% non-daily CU. Those who self-reported depression had higher prevalence of daily and non-daily CU than those not reporting depression. Daily CU was associated with 120% increased odds of depression (odds ratio = 2.2, 95% confidence interval [1.3, 3.7]) compared with none-users. Discussion Efforts to improve open communications and evidence-informed discussions regarding benefits and risks of CU and reasons for using cannabis between clinicians and cancer survivors are imperative.
... A literature review identified only two small RCTs on the use of cannabis in the treatment of anxiety disorders, which are described in detail in Appendix 1. Observational data indicate a strong and consistent association between cannabis use and anxiety and mood disorders, although causality has not been established. 45,46,47,48,49,50,51,52,53,54 Acute cannabis use can trigger anxiety and panic attacks, 55 and studies on animals and human volunteers suggest that high doses of cannabis actually worsen anxiety. 56 Cannabis use may worsen psychiatric impairment in patients with anxiety disorders. ...
Article
Full-text available
Under the Access to Cannabis for Medical Purposes (ACMPR)1 section of Canada’s cannabis regulations, which came into effect with the Cannabis Act on October 17, 2018, access to medical cannabis is authorized by a physician who signs a medical document. Authorized patients may purchase cannabis from a federally licensed producer, designate another person to produce it for them, or register to produce it themselves.2 Physicians do not prescribe cannabis since it is not a Health Canada–registered medication with a Drug Identification Number. The ACMPR medical document is an authorization for the use of cannabis for medical purposes, and, while the authorizing physician is encouraged to offer guidance on the form, strength, and dose, the dispensed form, dose, and titration are ultimately determined by the licensed producer. Under the Cannabis Act 2018, the use of cannabis for recreational purposes became legal (except for edible cannabis, cannabis extracts, and cannabis topicals, which became lawfully produced and sold as of October 17, 2019; see Table 1). Cannabis for recreational purposes differs from cannabis for medical purposes in that Health Canada does not regulate recreational cannabis production, possession, and distribution in the same way it does for cannabis for medical purposes. The basic facts and advice on safe consumption of recreational cannabis are summarized in the Government of Canada fact sheet.3 Provinces differ in their guidance and regulatory oversight for cannabis use.4 Provincial medical colleges, in the absence of regulatory oversight and approval, issued statements and guidance to comply with federal and provincial regulations (see the list of regulators provided under Recommendation 6). The Cannabis Act legalized recreational cannabis use and proposed a framework for the use of medical cannabis in Canada. However, it remains illegal to carry any cannabis with you when entering or leaving Canada, whether it is for medical or recreational purposes. Before cannabis use legalization, little research had been conducted on its therapeutic use, safety, or efficacy. This situation puts family physicians in a difficult position, as they are asked to authorize their patients’ access to a product with little evidence to support its use. To address this predicament, this document offers family physicians guidance on authorizing cannabis use for some specific conditions. Although the old Access to Cannabis for Medical Purposes regulations spoke only of use for medical purposes without specifying any diagnoses, the writing group chose chronic pain and anxiety as the original clinical areas of focus because they are the most common conditions for which a patient requests authorization. Since the original 2014 version was released, we have updated the document, added content, and broadened the scope of discussion beyond chronic pain and anxiety. Cannabis is the raw plant material, composed of hundreds of different compounds, that serves as the source for non-pharmaceutically produced medical cannabis, including material for smoking and vaping as well as for edibles and concentrates. The two chemicals from the cannabis plant discussed are tetrahydrocannabinol (THC) and cannabidiol (CBD).Research shows that cannabis could be a potent psychoactive substance with a risk of acute and chronic adverse effects of varying severity. Its most common acute effects include perceptual distortions, cognitive impairment, euphoria, and anxiety.5 Chronic use of cannabis may be associated with persistent neuropsychological deficits, even after a period of abstinence.6, 7 The frequency and intensity vary based on the proportional content of psychoactive ingredients and on other factors including extent of use, age of first use, and length of abstinence.8 Medium- and long-term therapeutic and adverse effects of medical and recreational cannabis have not been sufficiently studied. Products containing THC have a known abuse and dependence potential (liability). It is recommended that family physicians consider the anticipated therapeutic benefits versus potential harms for a patient’s health condition before authorizing initial or continuing cannabis use. As with any other therapeutic approach, continuing cannabis use is warranted only if the authorizing physician is satisfied that there has been improvement in the patient’s presenting symptoms (e.g., pain level), function, and/or quality of life; the risk of cannabis use disorder has been reassessed; and the benefits outweigh potential harms.
... In addition to nicotine and alcohol, cannabis is one of the most commonly used drugs (Volkow et al., 2014). Cannabis use during later adolescence and young adulthood, especially frequent use, has been linked with later illicit and problematic drug use (Blanco et al., 2016;Boden et al., 2020;Volkow et al., 2014); certain psychiatric disorders such as psychosis (Arseneault et al., 2002;Bourque et al., 2018;Fergusson et al., 2005b;Volkow et al., 2014), and poorer functional outcomes, including delinquency, and financial and social problems into midlife (Boden et al., 2020;Cerda et al., 2016;Degenhardt et al., 2013;Fergusson et al., 2002;Green et al., 2017;Horwood et al., 2012;Horwood et al., 2010;Silins et al., 2015;Silins et al., 2014;Taylor et al., 2017), and reduced intellectual ability (Meier et al., 2012) and educational attainment (Horwood et al., 2010;Silins et al., 2015;Silins et al., 2014). ...
Article
Full-text available
Background: Amidst cannabis legalization efforts and laws, we do not fully understand how the youngest frequent cannabis users fare during young adulthood. This study aims to 1) examine the prevalence of cannabis use during adolescence, and 2) investigate links of frequent (i.e., weekly or daily) teenage cannabis use with psychopathology and functional well-being at age 20-compared to no or occasional use. Methods: Data came from a prospective-longitudinal cohort study (assessments from 2004 to 2018, from ages 7-20) in an urban setting (N = 1482). Substance use was assessed with self-reports between ages 13 and 20. At age 20, participants reported on psychopathology (psychotic symptoms, problematic substance use, aggression, and internalizing symptoms) and functional well-being (delinquency, financial difficulties, social exclusion, general well-being, and not being in education, employment, or training). Covariates were based on self-, parent-, teacher-, and behavioral measures. Findings: Almost one in five adolescents had used cannabis frequently between ages 13 and 17 (26.6% of males, 9.8% of females). Adjusting nearly 20 potential confounders, frequent teenage cannabis use was associated with age 20 problematic substance use and poorer functional well-being compared to the no cannabis use and the occasional use groups. Frequent teenage cannabis use was more consistently associated with age 20 functional outcomes compared to frequent teenage nicotine or alcohol use. Conclusions: Frequent teenage cannabis use was common and associated with problematic substance use, more delinquency, and poorer functional well-being at age 20. Accordingly, frequent teenage cannabis users could experience increased difficulties in mastering the transitions of young adulthood.
... Mental health problems are associated with the use of marijuana, a drug most often used by justice-involved youth [18][19][20][21]. For example, longitudinal studies of adolescents demonstrate increased marijuana use is related to increased symptoms of depression over time [22,23]. When examining sex differences, most studies find the relationship between depression and marijuana use is stronger for boys, than girls [24,25]. ...
... A systematic review which controlled for baseline depression found that heavy cannabis use may be associated with an increased, though modest, risk for developing depression (Lev-Ran et al, 2013). A separate analysis found a dose-response relationship between cannabis use and depressive symptoms, with a highly significant effect across four separate Australian cohorts in the association between frequency of cannabis use and mean scores on depression measures (Horwood et al, 2012). However, again, without assessment of wider contextual factors, including baseline depression prior to the development of chronic skunk use, it would be difficult to draw any conclusions about causal relationships between cannabis use and depression in our sample. ...
Conference Paper
This thesis assesses psychotic-like symptomatology and reward responsivity in chronic users of two illicit drugs, cannabis and ketamine. As use of these drugs is steadily increasing, with cannabis being the most widely used drug worldwide (following alcohol, caffeine and tobacco) and the recent proliferation of ketamine misuse in parts of Asia, Europe and the United States, it is important to examine the effects of their habitual use. While research has linked cannabis use to sub-clinical psychotic-like symptoms, longitudinal studies examining the association between cannabis use, psychotic-like symptoms and transition to psychosis have revealed mixed findings. Additionally, although acute ketamine administration has been shown to produce psychotic-like symptoms in drug-naïve volunteers, there has been less research on the effects of chronic ketamine use. Part 1 of the thesis is a literature review investigating the assessment of cannabis use in studies of individuals meeting clinical ‘high risk’ criteria for transition to psychosis. It examines measures of cannabis use, as well as findings regarding the association between cannabis and subsequent conversion to psychosis. It also examines whether such studies measured further significant outcome variables, such as social and role functioning. Finally, the literature review considers the limitations in how cannabis use has been assessed and the implications of this for future research on the extent to which cannabis influences the development of psychotic-like symptomatology and risk of conversion to frank psychosis. Part 2 of the thesis comprises an investigation of symptoms of prodromal psychosis and reward responsiveness in three groups – chronic users of cannabis, ketamine, and healthy controls. This investigation formed part of a joint project conducted with one other trainee clinical psychologist examining the chronic effects of cannabis and ketamine use on psychosis proneness and cognitive functioning. The empirical paper reports a between subjects study, comparing 20 cannabis users, 20 ketamine users and 20 healthy controls on a number of self-report measures indexing depression (BDI-II), psychosis-like symptoms and schizotypy (PQ-B and O-LIFE), and trait anhedonia (TEPS), and on two laboratory-based tasks assessing reward sensitivity (the ‘Probabilistic Reward Task’) and effort-based decision making (the ‘Effort-Expenditure for Rewards Task’). Both drug using groups were found to have higher levels of schizotypy (O-LIFE) and positive psychosis symptomatology (PQ-B) than controls, while group differences were found on the probabilistic reward task, with controls demonstrating greater response bias than cannabis users and greater discriminability than ketamine users. No group differences were found on the effort-based decision-making task. A critical appraisal of the research forms Part 3 of the thesis. It describes the process of working collaboratively on the project rationale and design, reflections on recruiting and working with drug using participants, and thoughts on clinical implications of the project.
... The effect of cannabis use on later depression was claimed (but not yet replicated) to be moderated by the serotonin transporter gene, with greater risk for those carrying the short allele of the 5-HTTLPR genotype (Otten & Engels, 2013), and a similar effect was found on anxiety (Otten, Huizink, Monshouwer, Creemers, & Onrust, 2017). A weak age x cannabis interaction was found in a study of four Australian cohorts, suggesting a greater risk for adolescent cannabis use (Horwood et al., 2012). Furthermore, the synergistic effect of cannabis use and childhood maltreatment increased the risk of earlier onset, rapid cycling, and suicide attempt in BD (Aas et al., 2014). ...
Article
Objective: This review discusses the relationship between cannabis use and psychotic, bipolar, depressive, and anxiety disorders, as well as suicide. It summarizes epidemiological evidence from cross-sectional and long-term prospective studies and considers possible etiological mechanisms. Methods: Systematic reviews and methodologically robust studies in the field (from inception to February 2019) were identified using a comprehensive search of Medline, PsychINFO, and Embase and summarized using a narrative synthesis. Results: Consistent evidence, both from observational and experimental studies, has confirmed the important role of cannabis use in the initiation and persistence of psychotic disorders. The size of the effect is related to the extent of cannabis use, with greater risk for early cannabis use and use of high-potency varieties and synthetic cannabinoids. Accumulating evidence suggests that frequent cannabis use also increases the risk for mania as well as for suicide. However, the effect on depression is less clear and findings on anxiety are contradictory with only a few methodologically robust studies. Furthermore, the relationship with common mental disorders may involve reverse causality, as depression and anxiety are reported to lead to greater cannabis consumption in some studies. Pathogenetic mechanisms focus on the effect of tetrahydrocannabinol (THC, the main psychoactive ingredient of cannabis) interacting with genetic predisposition and perhaps other environmental risk factors. Cannabidiol (CBD), the other important ingredient of traditional cannabis, ameliorates the psychotogenic effects of THC but is absent from the high-potency varieties that are increasingly available. Conclusions: The evidence that heavy use of high-THC/low-CBD types of cannabis increases the risk of psychosis is sufficiently strong to merit public health education. Evidence of similar but smaller effects in mania and suicide is growing, but is not convincing for depression and anxiety. There is much current interest in the possibility that CBD may be therapeutically useful.
... When substance dependence was present, these figures jumped to 5.74 (4.07, 8.08) and 4.76 (3.28, 6.91) times for mood and anxiety disorders, respectively. More recently (9), explored the association between cannabis and depression in adolescents. With four cohorts and a total of 6,900 participants, increased use of cannabis led to increased symptoms of depression. ...
Article
Full-text available
Objectives: The aim of this paper is to assess the odds of suffering from anxiety or depression symptoms based on the presence of certain determinants of health for youth living in the province of New Brunswick, Canada, and in two linguistically different Official Language Minority Communities (OLMCs) in the same province. Methods: With a sample of 22,329 students from grades 7 to 12 in the province of New Brunswick, Canada, logistic regressions were performed to assess each determinant of health's effect on symptoms of anxiety and depression. Results: Some social determinants, like family support, social support and food insecurity, were identified as important determinants of mental health status regardless of linguistic group membership or community membership, while other determinants, such as alcohol use, cannabis use and natural environment, were more prominent in one OLMC than the other. Discussion: Social psychology and public health theories are used in an attempt to explain the results. Limitations and recommendations are also brought forward.
... For example, summary statistics from different samples may be combined using meta-analysis, which has a long history in statistics [9]. A more recent twist on meta-analysis is integrative data analysis (IDA), which uses pooled individual-level data from multiple sources [10][11][12]. In 2017, the National Academies of Sciences, Engineering and Medicine convened an expert panel that focused on data triangulation as a means to improve federal statistics for policy and research. ...
... It is not unusual for other common mental disorders, such as depression and anxiety, to co-occur with substance use disorders making the increasing importance of substance use treatment and management in global health for young people imperative [2]. Individuals who consume cannabis, tobacco, and alcohol are more likely to develop anxiety disorders or experience depression or even the less common psychotic disorders later in life [3][4][5][6][7][8]. Longitudinal studies have identified that heavy alcohol intake is frequently associated with increased suicide risk [9,10]. ...
... Recent data suggest that the prevalence of depression is also rising in the United States, especially among young people [20]. Historically, both clinical and epidemiological studies have found that cannabis use is consistently more prevalent among people with than those without depression [21][22][23][24]. Meta-analyses indicate that there is evidence for cannabis use-and heavy use, in particular-being causally related to the onset of affective disorders, including depression [21,25]. ...
Article
Aims: To estimate trends in the prevalence of cannabis use and risk perceptions of cannabis use from 2005-2017 among United States (U.S.) persons with and without depression. Design: Linear time trends of the prevalence of any, daily, and non-daily past-30-day cannabis use and perceived great risk associated with regular cannabis use (outcome variables) among persons with and without past-year depression were assessed using logistic regression with survey year as the predictor. All analyses were adjusted for gender, age, race/ethnicity, and income; models assessing time trends of cannabis use prevalence were also adjusted for perceived risk. Setting: The United States: National Survey on Drug Use and Health, an annual cross-sectional survey, 2005-2017 public use data files. Participants: 728,691 persons age ≥12 years. Measurements: Self-report of any, daily, and non-daily past-30-day cannabis use and perceived great risk associated with regular cannabis use. Findings: The prevalence of any, daily, and non-daily cannabis use in the past month was higher among those with depression versus those without (e.g., 2017 for any use: 18.94% vs. 8.67%; adjusted odds ratio (aOR)=2.17 (95% confidence interval (CI)=1.92, 2.45)). Any, daily, and non-daily cannabis use increased among persons with and without depression from 2005-2017, yet the increase in any (aORs=1.06 vs. 1.05; p=0.008) and daily (aORs=1.10 vs. 1.07; p=0.021) cannabis use adjusted for sociodemographic characteristics was more rapid among those with depression. Perception of great risk associated with regular cannabis use was significantly lower among those with depression (p<0.001) and decreased significantly more rapidly over the study period among persons with depression, compared with those without (aORs=0.89 vs. 0.92; p<0.001). Conclusions: The prevalence of cannabis use in the U.S. increased from 2005 to 2017 among persons with and without depression and was approximately twice as common among those with depression. Persons with depression experienced a more rapid decrease in perception of risk, which may be related to the more rapid increase in any and daily past-month cannabis use in this group.
... Extended use of cannabis was also associated with behavioral changes such as mania, depression, and mood disturbances. Cannabis dependency and addiction is another major challenge [130,131]. Cannabis use for a long term was also related with cognitive changes in a dose-related manner that also lead to road accidents. It also leads to long-term brain functional and structural changes [132,133]. ...
Article
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i>Cannabis sativa L. is an annual herbaceous dioecious plant which was first cultivated by agricultural human societies in Asia. Over the period of time, various parts of the plant like leaf, flower, and seed were used for recreational as well as therapeutic purposes. The main chemical components of Cannabis sativa are termed as cannabinoids, among them the key psychoactive constituent is Δ-9-tetrahydrocannabinol and cannabidiol (CBD) as active nonpsychotic constituent. Upon doing extensive literature review, it was found that cannabis has been widely studied for a number of disorders. Very recently, a pure CBD formulation, named Epidiolex, got a green flag from both United States Food and Drug Administration and Drug Enforcement Administration for 2 rare types of epilepsies. This laid a milestone in medical cannabis research. This review intends to give a basic and extensive assessment, from past till present, of the ethnological, plant, chemical, pharmacological, and legal aspects of C. sativa . Further, this review contemplates the evidence the studies obtained of cannabis components on Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis, multiple sclerosis, emesis, epilepsy, chronic pain, and cancer as a cytotoxic agent as well as a palliative therapy. The assessment in this study was done by reviewing in extensive details from studies on historical importance, ethnopharmacological aspects, and legal grounds of C. sativa from extensive literature available on the scientific databases, with a vision for elevating further pharmaceutical research to investigate its total potential as a therapeutic agent.
... From a clinical standpoint, there is an emerging consensus on how cannabis may confer some therapeutic benefits (treatments for chronic pain and glaucoma) 3,4 , and may also increase risk for adverse mental health outcomes (major mental illnesses and associated symptomatology) 5 . Specifically, cannabis use has been associated with increased risk for depressive 6 and anxiety disorders 7 , and, central to this review, psychosis spectrum disorders 8 . Cannabis use initiated during early adolescence confers the greatest risk for adult psychosis 9 , and dose-dependent cannabis use has been associated with an increased likelihood of developing psychosis and schizophrenia 8 while short-term cannabis use has been associated with increases in psychotic-like symptoms, such as altered perception and anxiety 10 . ...
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Acute exposure to cannabis has been associated with an array of cognitive alterations, increased risk for neuropsychiatric illness, and other neuropsychiatric sequelae including the emergence of acute psychotic symptoms. However, the brain alterations associating cannabis use and these behavioral and clinical phenotypes remains disputed. To this end, neuroimaging can be a powerful technique to non-invasively study the impact of cannabis exposure on brain structure and function in both humans and animal models. While chronic exposure studies provide insight into how use may be related to long-term outcomes, acute exposure may reveal interesting information regarding the immediate impact of use and abuse on brain circuits. Understanding these alterations could reveal the connection with symptom dimensions in neuropsychiatric disorders and, more specifically with psychosis. The purpose of the present review is to: 1) provide an update on the findings of pharmacological neuroimaging studies examining the effects of administered cannabinoids and 2) focus the discussion on studies that examine the sensitive window for the emergence of psychosis. Current literature indicates that cannabis exposure has varied effects on the brain, with the principal compounds in cannabis (delta-9-tetrahydrocannabinol and cannabidiol) altering activity across different brain regions. Importantly, we also discovered critical gaps in the literature, particularly regarding sex-dependent responses and long-term effects of chronic exposure. Certain networks often characterized as dysregulated in psychosis, like the default mode network and limbic system, were also impacted by THC exposure, identifying areas of particular interest for future work investigating the potential relationship between the two.
... It is hard to imagine how depression might affect a practising physician. Currently, research on PH from the perspective of anxiety and depression mainly focuses on related treatment studies, such as research on the treatment and application of anxiety [11][12][13]; analysis of the correlation between anxiety, cognition, and negative evaluation [14]; treatment of depression [15][16]); and correlations between depression, social stress, and other factors [17][18][19][20]. Recently, researchers showed evidence that anxiety and depression are related to the social environment and other factors [21][22]. ...
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Background The psychological health (PH) of doctors affects the quality of medical service and is related to the safety of patients. The serious problems with the doctor-patient relationship in China can lead to long-term imbalances in doctor PH, and the poor PH status of doctors has raised scholars’ concern. Current research mainly focuses on how factors such as social support and the impact of the residential environment correlate with individual PH. We continue this direction of research to see how the mechanism of social support impacts physician PH, also investigating the moderating effect of demographic indicators on physician PH. Methods Based on a survey of 399 physicians, a descriptive analysis of measured data was done using SPSS 19.0. Pearson correlation coefficient analysis was used to examine the correlations between PH and the social support rating scale (SSRS) and the demographic variables. KMO and Bartlett methods were used to examine the correlations between PH and SDS (a scale to measure depression) and between PH and SAS (a scale to measure anxiety). The method of factor analysis was used for multicollinearity tests, and multiple stepwise regression analysis was used to explore the demographic factors correlated with PH and SSRS. Two-way interactions in moderated multiple regression were used to test the moderating effect of education level and title on SSRS, SDS, and SAS. Results Our results indicate that the level of PH is influenced by the age, education, and title of a doctor. A physician’s title is significantly and positively correlated with PH, but age and education are significantly negatively related. Age, education, and title also affect the level of SSRS in physicians. SSRS is positively correlated with age, education, and title, and SSRS positively influences PH. Education and title had significant effects on the moderating influences of SSRS, SDS, SAS, and PH. Conclusion The factors directly affecting PH include SSRS, age, and title, while education was found to be an indirect influencing factor. To meet goals expressed in Chinese government policy related to these issues, we suggest strengthening the guidance of the media, introducing laws and regulations on doctor-patient risk management and control, reforming the review mechanism of hospital job titles, improving the education level of doctors, building a comprehensive evaluation system of “practice performance + doctor-patient satisfaction”, and strengthening doctor-patient empathy. Through such measures, the level of PH in physicians will improve.
Article
Background and objectives: Maladaptive decision-making strategies could contribute to cannabis-related problems, as some individuals may neither select safe patterns of cannabis use, nor seek treatment. Methods: To explore decision-making styles and their relationship to cannabis-related harm, 153 respondents completed the Cannabis Use Disorders Identification Test-Revised (CUDIT-R), the Melbourne Decision Making Questionnaire (MDMQ), and answered questions about their willingness to seek online: (1) further information or (2) treatment for cannabis-related issues. Results: Multiple regression considered relationships between problematic cannabis use, decision-making style, and cannabis use within the past month. Subscales of the CUDIT-R revealed that: (1) hazardous use was associated with higher hypervigilance and higher decisional self-esteem; (2) dependence symptoms were associated with lower vigilance and higher procrastination; and (3) harmful use was associated with higher procrastination. People with symptoms of CUD were less likely to seek further help or support online if prone to procrastination or buckpasssing. Discussion and conclusions: Decisional style influenced cannabis use and symptoms. Those people with cannabis-related problems that did not seek online assistance were defensively avoidant. Scientific significance: Procrastination is a feature of problematic cannabis use. Online offers of assistance may be ignored by defensively avoidant CUD clients. (Am J Addict 2019;00:1-7).
Article
El consumo de sustancias y la sintomatología depresiva no están ausentes en las poblaciones universitarias, por lo tanto, existe un interés por estudiar su interacción, ya que puede comprometer negativamente el bienestar de los estudiantes. Objetivo: Analizar el consumo de sustancias y sintomatología depresiva en universitarios por área académica y género. Materiales y métodos. Estudio transversal, correlacional. 4543 universitarios previo consentimiento voluntario y anónimo diligenciaron la Escala de Goldberg, Test de Fagerstrom, AUDIT y CAST. Los datos se analizaron con estadística descriptiva e inferencial de t de Student, Anova y Rho de Spearman. Resultados. Las mujeres presentan mayor sintomatología depresiva que los hombres. Los estudiantes de ciencias de la salud que tienen sintomatología depresiva, presentan alto consumo de alcohol, tabaco y marihuana. La dependencia de consumo de tabaco y el consumo de marihuana de riesgo moderado, prevalece en mujeres y hombres con sintomatología depresiva. Las mujeres con sintomatología depresiva consumen alcohol excesivamente y los hombres tienen síntomas de dependencia. La sintomatología depresiva en hombres y mujeres se incrementa ante el policonsumo de sustancias. Existe correlación positiva moderada entre el consumo de tabaco y alcohol. Conclusiones. El estudio sienta precedente para la conducción de estudios con modelos causales y longitudinales durante el tránsito por la universidad. Es prioritario en la comunidad universitaria de incluir en los planes de estudios y módulos psicopedagógicos un programa multidisciplinario de atención oportuna de salud mental.
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Marijuana is the dried leaves, stems, and flowers of a 1- to 5-m weed originating from Central Asia. The most common varieties are Cannabis sativa and Cannabis indica. It is usually inhaled as smoke but can also be used as a vapor, taken by mouth as a spray, ingested in tea or as butter in baked goods, or in capsule form and used as an oil. Cannabis has been widely used to treat many medical conditions such as multiple sclerosis symptoms, mood disorders, pain, sleep disorders, and seizures among others. Preclinical and clinical studies have been done over the past decade, among them there are few randomized placebo-controlled trials. In the last few years, Cannabis has been proposed as a potential therapy for patients with drug-resistant epilepsy. This review analyzes the best information about the use of cannabis in adult patients, reviewing aspects of efficacy and safety.
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El consumo de sustancias y la sintomatología depresiva no están ausentes en las poblaciones universitarias, por lo tanto, existe un interés por estudiar su interacción, ya que puede comprometer negativamente el bienestar de los estudiantes. Objetivo: Analizar el consumo de sustancias y sintomatología depresiva en universitarios por área académica y género. Materiales y métodos. Estudio transversal, correlacional. 4543 universitarios previo consentimiento voluntario y anónimo diligenciaron la Escala de Goldberg, Test de Fagerstrom, AUDIT y CAST. Los datos se analizaron con estadística descriptiva e inferencial de t de Student, Anova y Rho de Spearman. Resultados. Las mujeres presentan mayor sintomatología depresiva que los hombres. Los estudiantes de ciencias de la salud que tienen sintomatología depresiva, presentan alto consumo de alcohol, tabaco y marihuana. La dependencia de consumo de tabaco y el consumo de marihuana de riesgo moderado, prevalece en mujeres y hombres con sintomatología depresiva. Las mujeres con sintomatología depresiva consumen alcohol excesivamente y los hombres tienen síntomas de dependencia. La sintomatología depresiva en hombres y mujeres se incrementa ante el policonsumo de sustancias. Existe correlación positiva moderada entre el consumo de tabaco y alcohol. Conclusiones. El estudio sienta precedente para la conducción de estudios con modelos causales y longitudinales durante el tránsito por la universidad. Es prioritario en la comunidad universitaria de incluir en los planes de estudios y módulos psicopedagógicos un programa multidisciplinario de atención oportuna de salud mental. Palabras clave: Depresión, Adulto jóven, Dependencia de tabaco, Consumo de bebidas alcohólicas, Uso de marihuana (Fuente: Decs, Bireme).
Article
Importance: Cannabis use disorder (CUD) is increasing in the US. Clarification of the potential mechanisms underlying the comorbidity between mood disorders and CUD may help prevent CUD. Objective: To examine co-occurrence and familial aggregation of CUD and mood disorder subtypes. Design, setting, and participants: In this cross-sectional, community-based study in the Washington, DC, metropolitan area, semistructured diagnostic interviews and family history reports assessed lifetime DSM-IV disorders in probands and relatives. Familial aggregation and coaggregation of CUD with mood disorders were estimated via mixed-effects models, adjusting for age, sex, recruitment source, and comorbid mood, anxiety, and other substance use disorders. A total of 586 adult probands (186 with bipolar disorder; 55 with CUD) and 698 first-degree relatives (91 with bipolar disorder; 68 with CUD) were recruited from a community screening of the greater Washington, DC, metropolitan area from May 2004 to August 2020. Inclusion criteria were ability to speak English, and availability and consent to contact at least 2 living first-degree relatives. Main outcomes and measures: Lifetime CUD in first-degree relatives. Results: Of 586 probands, 395 (67.4%) were female; among 698 relatives, 437 (62.6%) were female. The mean (SD) age was 47.5 (15.2) years for probands and 49.6 (18.0) years for relatives. In the proband group, 82 participants (14.0%) self-identified as African American or Black, 467 (79.7%) as White, and 37 (6.3%) as American Indian or Alaska Native, Asian, more than one race, or another race or ethnicity or declined to respond. In the relative group, 53 participants (7.6%) self-identified as African American or Black, 594 (85.1%) as White, and 51 (7.3%) as American Indian or Alaska Native, Asian, more than one race, or another race or ethnicity or declined to respond. These groups were combined to protect privacy owing to small numbers. CUD in probands (55 [9.4%]) was associated with an increase in CUD in relatives (adjusted odds ratio [aOR], 2.64; 95% CI, 1.20-5.79; P = .02). Bipolar disorder II (BP-II) in probands (72 [12.3%]) was also associated with increased risk of CUD in relatives (aOR, 2.57; 95% CI, 1.06-6.23; P = .04). However, bipolar disorder I (114 [19.5%]) and major depressive disorder (192 [32.8%]) in probands were not significantly associated with CUD in relatives. Among relatives, CUD was associated with BP-II (aOR, 4.50; 95% CI, 1.72-11.77; P = .002), major depressive disorder (aOR, 3.64; 95% CI, 1.78-7.45; P < .001), and mean (SD) age (42.7 [12.8] years with CUD vs 50.3 [18.3] years without CUD; aOR, 0.98; 95% CI, 0.96-1.00; P = .02). Familial coaggregation of BP-II with CUD was attenuated by the inclusion of comorbid anxiety disorders. Further, rates of CUD were highest in relatives with both a familial and individual history of BP-II (no familial or individual history of BP-II: 41 [7.2%]; familial history but no individual history of BP-II: 13 [19.1%]; individual history but no familial history of BP-II: 10 [22.2%]; familial and individual history of BP-II: 4 [28.6%]; Fisher exact test, P < .001). The onset of mood disorder subtypes preceded CUD in probands and relatives in most cases. Conclusions and relevance: The findings confirmed a familial aggregation of CUD. The increase in risk of CUD among relatives of probands with BP-II suggests that CUD may share a common underlying diathesis with BP-II. Taken together with the temporal precedence of depression and mania with respect to CUD onset, these findings highlight a potential role for BP-II intervention as CUD prevention.
Article
Decriminalization, medicalization, and legalization of cannabis use by a majority of U.S. states over the past 25 years have dramatically shifted societal perceptions and use patterns among Americans. How marijuana policy changes have affected population-wide health of U.S. youth and what the downstream public health implications of marijuana legalization are topics of significant debate. Cannabis remains the most commonly used federally illicit psychoactive drug by U.S. adolescents and is the main drug for which U.S. youth present for substance use treatment. Converging evidence indicates that adolescent-onset cannabis exposure is associated with short- and possibly long-term impairments in cognition, worse academic/vocational outcomes, and increased prevalence of psychotic, mood, and addictive disorders. Odds of negative developmental outcomes are increased in youth with early-onset, persistent, high frequency, and high-potency Δ-9-THC cannabis use, suggesting dose-dependent relationships. Cannabis use disorders are treatable conditions with clear childhood antecedents that respond to targeted prevention and early intervention strategies. This review indicates that marijuana policy changes have had mixed effects on U.S. adolescent health including potential benefits from decriminalization and negative health outcomes evidenced by increases in cannabis-related motor vehicle accidents, emergency department visits, and hospitalizations. Federal and state legislatures should apply a public health framework and consider the possible downstream effects of marijuana policy change on paediatric health.
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This study tested whether increases in recent and cumulative cannabis use were each associated with increases in internalizing problems from adolescence to young adulthood. Participants were boys from a community sample that was assessed annually from ~age 15–26 (N = 506). Boys reported on their cannabis use, depression symptoms, and anxiety/depression problems each year. Exposures were frequency of cannabis use in a given year (no use, < weekly use, weekly or more frequent use) and cumulative prior years of weekly cannabis use. Outcomes were depression symptoms and anxiety/depression problems in a given year. Analyses examined within-person associations between changes in exposures and outcomes over time, which eliminated “fixed” (unchanging) individual differences as potential confounds. Analyses also accounted for time-varying factors as potential confounds (other substance use, externalizing problems, subclinical psychotic symptoms). Results showed that increases in recent cannabis use and cumulative prior years of weekly cannabis use were each associated with increases in depression symptoms and anxiety/depression problems. After controlling for time-varying covariates, increases in cumulative prior years of weekly cannabis use, but not recent cannabis use, remained associated with increases in depression symptoms and anxiety/depression problems. Specifically, each additional year of prior weekly cannabis use was associated with a small increase in depression symptoms (b = 0.012, p = .005) and anxiety/depression problems (b = 0.009, p = .001). Associations did not vary systematically across time. There was also no evidence of reverse causation. As boys engaged in weekly cannabis use for more years, they showed increases in internalizing problems, suggesting the importance of preventing chronic weekly cannabis use.
Article
Background To clarify the direction of the association between frequency of cannabis use, depressive symptoms and suicidal ideation from 15 to 20 years using cross-lagged analyses. Method We included 1606 adolescents from the province of Québec followed since 1997 with information on frequency of cannabis use (none/monthly/weekly), depression (defined as being in the top 10% symptoms) and serious suicidal ideation at ages 15, 17 and 20 years. Results The prevalence of weekly cannabis use increased from 7.0% at age 15 years to 15.6% by age 20 years. Adolescents who reported using cannabis weekly at one age were 11 to 15 times more likely to continue using cannabis over time. In longitudinal cross-lagged analyses, weekly cannabis use at age 15 was associated with greater odds (OR:2.19, 95% CI:1.04-4.58) of suicidal ideation two years later. However, other substance use (alcohol, tobacco, other drugs) fully explained this association. Further, depression predicted subsequent weekly cannabis use, even after adjusting for comorbid other substance use (eg, for depression at 15 years predicting cannabis use at 17 years: OR:2.30, 95% CI:1.19-4.43). Limitations Quantity of cannabis consumed was not measured. Conclusion Findings suggest that depressive symptoms in adolescence may represent a risk factor for weekly cannabis consumption, which once initiated is likely to remain chronic. Weekly cannabis use increased risk for suicidal ideation, but not independently from other substance use including alcohol, tobacco and other drugs.
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Cannabis and Young Pediatric Exposures Adult recreational and medical use of marijuana and related products impacts the entire pediatric population. Exposures begin as early as the prenatal and postpartum time period, including pregnancy and breastfeeding exposures from both recreational and medical use to treat pregnancy-related conditions such as morning sickness, hyperemesis gravidarum, or postpartum pain, depression, or anxiety. Young children are subject to passive (secondhand) smoke exposures when caregivers use within the home or car environments. When marijuana products, such as edibles, are poorly stored, there are risks for unintentional ingestions leading to a spectrum of clinical symptoms. Marijuana is also used for medicinal indications in the pediatric population as in the adult population, with limited amount of evidenced-based literature to support its use. This chapter discussed the evidence behind marijuana exposures in young children. Cannabis and the Teen Brain This chapter discusses the potential damage that cannabis consumption poses for the central nervous system (CNS) of adolescents. It begins with a summary of normal adolescent growth and development that includes the need for a normal and healthy CNS that is rapidly growing and changing. Research data are then summarized that reveal the toxic effects that cannabis exposure can have for our youth with damage to their sensitive, rapidly maturing CNSs. These tragic results can include cognitive dysfunction, drug dependences, various neuropsychiatric disorders, and other sequelae. The conclusion from viewing such data over many decades is that cannabis is a toxin that our youth should avoid because of the potential irreversible damage it can do to normal adolescence and normal adulthood.
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Background: Previous studies have shown that medical students are more prone to suffer from symptoms related to depression than other students. Even though there is some evidence that psychology students also experience such symptoms, research concerning the mental health of future psychologists is scarce. Objective: The aims of this study were threefold: (a) to determine the prevalence of symptoms related to depression among medical and psychology students (b) to investigate risk factors, which may have a potential influence on the development of depressive symptoms and (c) to examine resilience factors in order to indicate possible approaches to improve the mental health of the students. Methods: A total of 673 medical and psychology students completed the Beck Depression Inventory-II (BDI-II) to assess depressive symptoms, a neuroticism scale, and a standardized questionnaire for 13 risk and eight resilience factors derived from the literature. Results: While the results of previous research concerning the prevalence of depressive symptoms could be replicated for medical students (22% exceeding the cut-off in the BDI-II), psychology students demonstrated an even higher prevalence (28%). Ten potential risk factors and five potential resilience factors could be identified, which also showed a cumulative effect: The more risk factors students reported, the more depressive symptoms they experienced; the inverse effect was observed for resilience factors. Conclusions: Not only medical but also psychology students show elevated depressive symptomatology. In the university context, notably, the pressure to perform represents a potential risk factor, whereas the presence of just two resilience factors such as emotional support and study satisfaction contribute to a decrease of symptoms.
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Background: The COVID-19 pandemic has affected people worldwide. Desperate times (SARS COV-2 being a novel virus) called in for desperate measures in that right from its containment strategies to failed treatment trials have had various ramications affecting various spheres of our lives. It has already been established that the pandemic has taken a toll on mental health, cutting across all strata of society. However, apart from the pandemic in it itself as a causative factor, there are various other factors contributing to the increase in the mental health burden; some of which are modiable. An in-depth understanding of these modiable risk factors is the need of the hour, so that policies and guidelines can be framed accordingly to salvage what can be; of the mental health of the population at large. Understanding these modiable risk factors are lessons learned which will help us mitigate the mental health morbidity during the subsequent waves of the Pandemic. Aim: To study the prevalence and factors associated with the psychiatric morbidity in the general population during the COVID - 19 pandemic. Methods: The data was collected by snowball sampling using an online form to collect the demographic and clinical variables with the DASS - 21 scale appended. Conclusion: The prevalence of depression and anxiety was found to be 25.3 % and 26.2 % respectively. The signicant factors associated with psychiatric morbidity ranged across the psychological biological and social domains, some non-modiable whilst others modiable risk factors. The modiable factors identied were substance use, past history of psychiatric illness, chronic physical illness, increased screen time use, watching news (online) about the pandemic, working hours, disruption of a daily routine and a change in the lifestyle of people
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Introduction: Canadian youth consume cannabis in multiple ways, including by smoking, vaping, and eating or drinking. Existing evidence suggests that these behaviours may change after law liberalization, though data regarding youth are scarce. We investigated changes in cannabis modes of use and associated factors across the federal legalization of recreational cannabis use for adults in Canada, among a large sample of underage youth before alternative products were made legally available. Methods: Data were available from 2953 longitudinally linked Canadian high school students who reported on their cannabis use during the 2017/2018 and 2018/2019 school years. We explored whether students maintained a single or multiple cannabis use mode(s), contracted, or expanded the number of modes used. We then used generalized estimating equations to analyse associations of baseline characteristics with use mode trajectory. Results: Expansion of cannabis use modes (42.3%) was more common than maintenance of a single mode (31.3%), maintenance of multiple modes (14.3%), or reduction (12.1%). Students who maintained multiple modes were significantly more likely to have high amounts of weekly spending money (AOR 1.68), to binge drink (AOR 2.25) or vape (AOR 1.99), to use cannabis regularly (AOR 2.67), and to endorse more symptoms of depression (AOR 1.06). School support for quitting tobacco, drug, or alcohol use appeared to have no effect. Conclusions: Multi-modal cannabis use increased among Canadian youth in our sample. Its association with other substance use and depressive symptoms may indicate clustering of additional harms. Screening for this use pattern may assist in identifying high-risk substance use and should be considered in the design of harm reduction programming.
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Background and aim: Evidence suggests a positive association between cannabis use and depression however whether preconception cannabis use is associated with postpartum depression (PPD) remains unknown. This study examined the association using a longitudinal design. Methods: Participants were from the Australian Longitudinal Study on Women's Health (cohort born in 1989-95), a sample broadly representative of similarly aged Australian women. The association of past year cannabis use at 3-15 months prior to pregnancy with PPD at ages 19-24 to 22-27 was examined in 516 women with 570 singleton live births. The associations of chronicity, recency, and initiation of cannabis use before pregnancy with PPD at ages 21-26 to 24-29 were investigated in 538 women with 590 singleton live births. PPD was ascertained from self-report of doctor diagnosis for each birth. Relative risk (RR) and 95 % confidence interval (CI) were used to calculate the associations of interest. Results: Compared with no cannabis use, any past-year cannabis use at 3-15 months before pregnancy may be associated with an increased risk of PPD (1.50, 0.99-2.28). Compared with no cannabis use in the first three annual surveys before pregnancy, chronic use (a past year user in ≥ 2 surveys) was associated with an 80 % higher risk of incident PPD for births in the following 1-4 years (1.80, 1.22-2.68). Compared to never users at ages 20-25, former users who had no use within the past year had no increased risk; past year users had 73 % higher risk (1.73, 1.07-2.81); and past year users who initiated cannabis use at or after age 18 had twice the risk of incident PPD for births in the following 1-4 years (2.02, 1.17-3.49). Conclusion: This study provides evidence that preconception cannabis use is associated with increased risk of PPD. More studies are warranted to confirm this finding before cannabis cessation policies can be reinforced on reducing the risk of PPD.
Article
Cannabis use is linked to symptoms of depression and anxiety, particularly among sexual minorities. This study examines the relationships between cannabis, and depression and anxiety symptoms at 13, 15, and 17 years using cross-lagged models in a predominantly White (n = 1,430; 92%) subsample of 1,548 participants from the Quebec Longitudinal study of Child Development. Multigroup analyses were conducted to examine the models according to sexual orientation. Demographic covariates were included as control variables, as well as alcohol, cigarette, and other drug use to examine cannabis specificity. The full sample revealed small bidirectional associations, which remained significant once control variables were included in the model: cannabis at 13 and 15 years predicted anxiety symptoms at 15 and 17 years respectively, and depression symptoms at 15 years predicted cannabis at 17 years. The initial association between cannabis at 13 years and depression symptoms at 15 years was accounted for by other drug use at 13 years. Substantial differences were found between heterosexual participants and sexual minorities: LGB participants presented a substantially larger positive association between depression symptoms at 15 years and cannabis at 17 years, as well as a negative association between anxiety symptoms at 15 years and cannabis at 17 years. Both of these relationships remained significant when accounting for control variables. These results suggest that the relationships between cannabis, and depression and anxiety symptoms are bidirectional across adolescence, albeit small. Sexual minorities present particularly large associations that may represent self-medication efforts for depressive symptoms between 15 and 17 years. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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Objective Research on associations of early cannabis use with adult functioning reports mixed findings. This may be due, in part, to wide variations in the definitions of early cannabis use. This study aims to compare associations of four commonly-used definitions of early cannabis use—related to timing, dose, duration, and associated symptoms—with adult outcomes. Method Analyses were based on a 20⁺-year longitudinal, community-representative study of 1,420 participants. Between ages 9 to 21 (8,806 observations) participants were assessed for cannabis use and DSM 5 Cannabis Use Disorder. In early adulthood (ages 24-26 and 30; 2,424 observations of 1,266 subjects), participants were also assessed for psychiatric, substance use, and functional outcomes. Results All definitions of early use were associated with multiple adult outcomes in models that adjusted for sex and race/ethnicity. In models that also adjusted for childhood psychiatric problems and family adversities, only daily use and a persistent developmental subtype (defined as daily/problematic use that began in adolescence and continued into early adulthood) were associated with later substance use/disorders, poorer functional outcomes, and derailments in the transition to adulthood. Conclusion Daily, continued-over-time cannabis use beginning on adolescence was most problematic for a range of adult outcomes. Cessation of early use did not fully eliminate later risks; but was associated with fewer negative outcomes, with weaker effect sizes.
Chapter
This chapter describes a case study conducted within an innovative juvenile assessment facility that examined the relationships among depression, age, race/ethnicity, age at first arrest, drug involvement, and sexual behaviors among youth in the criminal justice system. After a thorough discussion of the results, implications for larger services and practices are presented.
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The purpose of the present study was to describe the development and assess the psychometric properties of the Short Mood and Feelings Questionnaire (SMFQ). The SMFQ is a brief, easy-to-administer, self-report measure of childhood and adolescent depression, designed for the rapid evaluation of core depressive symptomatology or for use in epidemiological studies. The SMFQ's content and criterion-related validity were examined in a sample of 173 8-16 year-olds, comprised of both psychiatric and unselected pediatric controls. Results revealed substantial correlations between the SMFQ, the Children's Depression Inventory (CDI) and the Diagnostic Interview Schedule for Children (DISC) depression scale. The SMFQ successfully discriminated the clinically-referred psychiatric subjects from the pediatric controls. Within the pediatric (general population) sample, the SMFQ discriminated DISC-diagnosed children with depressive disorder from non-depressed subjects. Exploratory factor analyses, along with a high internal consistency, suggested that the SMFQ was a unifactorial scale. In sum, the SMFQ appears to be a promising tool for both the swift assessment of core depressive symptomatology and as a screening measure for depression in child psychiatric epidemiological studies.
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To determine whether use of cannabis in adolescence increases the risk for psychotic outcomes by affecting the incidence and persistence of subclinical expression of psychosis in the general population (that is, expression of psychosis below the level required for a clinical diagnosis). Analysis of data from a prospective population based cohort study in Germany (early developmental stages of psychopathology study). Population based cohort study in Germany. 1923 individuals from the general population, aged 14-24 at baseline. Incidence and persistence of subthreshold psychotic symptoms after use of cannabis in adolescence. Cannabis use and psychotic symptoms were assessed at three time points (baseline, T2 (3.5 years), T3 (8.4 years)) over a 10 year follow-up period with the Munich version of the composite international diagnostic interview (M-CIDI). In individuals who had no reported lifetime psychotic symptoms and no reported lifetime cannabis use at baseline, incident cannabis use over the period from baseline to T2 increased the risk of later incident psychotic symptoms over the period from T2 to T3 (adjusted odds ratio 1.9, 95% confidence interval 1.1 to 3.1; P=0.021). Furthermore, continued use of cannabis increased the risk of persistent psychotic symptoms over the period from T2 to T3 (2.2, 1.2 to 4.2; P=0.016). The incidence rate of psychotic symptoms over the period from baseline to T2 was 31% (152) in exposed individuals versus 20% (284) in non-exposed individuals; over the period from T2 to T3 these rates were 14% (108) and 8% (49), respectively. Cannabis use is a risk factor for the development of incident psychotic symptoms. Continued cannabis use might increase the risk for psychotic disorder by impacting on the persistence of symptoms.
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People who use cannabis have an increased risk of psychosis, an effect attributed to the active ingredient Delta 9-tetrahydrocannabinol (Delta 9-THC). There has recently been concern over an increase in the concentration of Delta 9-THC in the cannabis available in many countries. To investigate whether people with a first episode of psychosis were particularly likely to use high-potency cannabis. We collected information on cannabis use from 280 cases presenting with a first episode of psychosis to the South London & Maudsley National Health Service (NHS) Foundation Trust, and from 174 healthy controls recruited from the local population. There was no significant difference between cases and controls in whether they had ever taken cannabis, or age at first use. However, those in the cases group were more likely to be current daily users (OR = 6.4) and to have smoked cannabis for more than 5 years (OR = 2.1). Among those who used cannabis, 78% of the cases group used high-potency cannabis (sinsemilla, 'skunk') compared with 37% of the control group (OR 6.8). The finding that people with a first episode of psychosis had smoked higher-potency cannabis, for longer and with greater frequency, than a healthy control group is consistent with the hypothesis that Delta 9-THC is the active ingredient increasing risk of psychosis. This has important public health implications, given the increased availability and use of high-potency cannabis.
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The association between level of cannabis consumption and development of schizophrenia during a 15-year follow-up was studied in a cohort of 45,570 Swedish conscripts. The relative risk for schizophrenia among high consumers of cannabis (use on more than fifty occasions) was 6.0 (95% confidence interval 4.0-8.9) compared with non-users. Persistence of the association after allowance for other psychiatric illness and social background indicated that cannabis is an independent risk factor for schizophrenia.
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To aid general practitioners and other non-psychiatrists in the better recognition of mental illness short scales measuring anxiety and depression were derived by latent trait analysis from a standardised psychiatric research interview. Designed to be used by non-psychiatrists, they provide dimensional measures of the severity of each disorder. The full set of nine questions need to be administered only if there are positive answers to the first four. When assessed against the full set of 60 questions contained in the psychiatric assessment schedule they had a specificity of 91% and a sensitivity of 86%. The scales would be used by non-psychiatrists in clinical investigations and possibly also by medical students to familiarise them with the common forms of psychiatric illness, which are often unrecognised in general medical settings.
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General population survey data are used to disaggregate the associations of substance use disorders with suicide attempts in order to evaluate a number of hypotheses about the processes leading to these associations. Data are from the US National Comorbidity Survey (1990-1992). Discrete-time survival analysis is used to study the effects of retrospectively reported temporally prior substance use, abuse, and dependence in predicting first onset of suicidal behavior. Alcohol and drug use predict subsequent suicide attempts after controlling for sociodemographics and comorbid mental disorders. Previous use is not a significant predictor among current nonusers. Abuse and dependence are significant predictors among users for three of the 10 substances considered (alcohol, inhalants, and heroin). The number of substances used is more important than the types of substances used in predicting suicidal behavior. Disaggregation shows that the effects of use are largely on suicidal ideation and nonplanned attempts among ideators. In comparison, the effects of use on suicide plans and planned attempts among ideators are not significant. Clinicians need to be aware that current substance use, even in the absence of abuse or dependence, is a significant risk factor for unplanned suicide attempts among ideators.
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This study sought to estimate the degree to which cannabis abuse is a risk factor for depressive symptoms rather than an effort to self-medicate depression. Participants (N=1,920) in the 1980 Baltimore Epidemiologic Catchment Area (ECA) study who were reassessed between 1994 and 1996 as part of a follow-up study provided the data. The analysis focused on two cohorts: those who reported no depressive symptoms at baseline (N=849) and those with no diagnosis of cannabis abuse at baseline (N=1,837). Symptoms of depression, cannabis abuse, and other psychiatric disorders were assessed with the Diagnostic Interview Schedule. In participants with no baseline depressive symptoms, those with a diagnosis of cannabis abuse at baseline were four times more likely than those with no cannabis abuse diagnosis to have depressive symptoms at the follow-up assessment, after adjusting for age, gender, antisocial symptoms, and other baseline covariates. In particular, these participants were more likely to have experienced suicidal ideation and anhedonia during the follow-up period. Among the participants who had no diagnosis of cannabis abuse at baseline, depressive symptoms at baseline failed to significantly predict cannabis abuse at the follow-up assessment. Further research is needed to identify characteristics of individuals who abuse cannabis that account for their higher risk of depression to estimate the degree of impairment resulting from their depression.
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There is concern in the community about increasing cannabis use and its potential effect on health. To ascertain the prevalence of cannabis use among Australian adolescents, associations with mental health problems, risk behaviours and service use. Examination of data from a national representative sample of households comprising 1261 adolescents aged 13-17 years. Parents completed a psychiatric interview and questionnaires while adolescents completed questionnaires. One-quarter of the adolescents in the sample had used cannabis. There were no gender differences. Use increased rapidly with age, was more common in adolescents living with a sole parent and was associated with increased depression, conduct problems and health risk behaviours (smoking, drinking) but not with higher use of services. Cannabis use is very prevalent. The association with depression, conduct problems, excessive drinking and use of other drugs shows a malignant pattern of comorbidity that may lead to negative outcomes.
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Cannabis use may increase the risk of psychotic disorders and result in a poor prognosis for those with an established vulnerability to psychosis. A 3-year follow-up (1997-1999) is reported of a general population of 4,045 psychosis-free persons and of 59 subjects in the Netherlands with a baseline diagnosis of psychotic disorder. Substance use was assessed at baseline, 1-year follow-up, and 3-year follow-up. Baseline cannabis use predicted the presence at follow-up of any level of psychotic symptoms (adjusted odds ratio (OR) = 2.76, 95% confidence interval (CI): 1.18, 6.47), as well as a severe level of psychotic symptoms (OR = 24.17, 95% CI: 5.44, 107.46), and clinician assessment of the need for care for psychotic symptoms (OR = 12.01, 95% CI: 2.24, 64.34). The effect of baseline cannabis use was stronger than the effect at 1-year and 3-year follow-up, and more than 50% of the psychosis diagnoses could be attributed to cannabis use. On the additive scale, the effect of cannabis use was much stronger in those with a baseline diagnosis of psychotic disorder (risk difference, 54.7%) than in those without (risk difference, 2.2%; p for interaction = 0.001). Results confirm previous suggestions that cannabis use increases the risk of both the incidence of psychosis in psychosis-free persons and a poor prognosis for those with an established vulnerability to psychotic disorder.
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outline what we regard as the major conceptual issues related to the boundaries and overlap between psychiatric disorders, and discuss available approaches to studying these problems / draw on this literature to illustrate particular conceptual and methodological issues conceptual issues [discreteness, categorical vs dimensional models] / discovering and confirming boundaries between disorders [multimodality, cluster