Cannabis use at a young age is associated with psychotic experiences

Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, Department of Psychiatry, The Netherlands.
Psychological Medicine (Impact Factor: 5.94). 10/2010; 41(6):1-10. DOI: 10.1017/S003329171000187X
Source: PubMed


BACKGROUND: Cannabis use is associated with psychosis and a range of subclinical psychiatric symptoms. The strength of this association depends on dosage and age at first use. The current study investigates whether level of cannabis exposure and starting age are associated with specific profiles of subclinical symptoms.MethodWe collected cross-sectional data from a young adult population sample by administering an online version of the Community Assessment of Psychic Experiences (CAPE). Cannabis exposure was quantified as the amount of Euros spent on cannabis per week and the age of initial cannabis use. The primary outcome measure was the odds ratio (OR) to belong to the highest 10% of scores on the total CAPE and the positive-, negative- and depressive symptom dimensions. RESULTS: In 17 698 adolescents (mean age 21.6, s.d.=4.2 years), cannabis use at age 12 years or younger was strongly associated with a top 10% score on psychotic experiences [OR 3.1, 95% confidence interval (CI) 2.1-4.3] and to a lesser degree with negative symptoms (OR 1.7, 95% CI 1.1-2.5). The OR of heavy users (>€25/week) for negative symptoms was 3.4 (95% CI 2.9-4.1), for psychotic experiences 3.0 (95% CI 2.4-3.6), and for depressive symptoms 2.8 (95% CI 2.3-3.3). CONCLUSIONS: Early start of cannabis use is strongly associated with subclinical psychotic symptoms and to a lesser degree with negative symptoms, while smoking high amounts of cannabis is associated with increased levels of all three symptom dimensions: psychotic, negative and depressive. These results support the hypothesis that the impact of cannabis use is age specific.

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Available from: Marco PM Boks, Jun 10, 2015
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    • "Adolescent illicit drug use is common in Western society, with early initiation and frequent use being associated with increased risks of academic failure (Fergusson et al. 2007) and mental health problems, e.g., depression (de Graaf et al. 2010) and psychosis (Henquet et al. 2005; Schubart et al. 2011; Smit et al. 2004; Van Os et al. 2002). Almost a third (29 %) of European 15-to 16-year-olds have used cannabis (Hibell et al. 2012). "
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    ABSTRACT: In order to quantify the effectiveness of family interventions in preventing and reducing adolescent illicit drug use, we conducted a systematic review and meta-analysis of randomized controlled trials. We searched the Cochrane Database of Systematic Reviews, Educational Research Information Centre (ERIC), MEDLINE, Embase, and PsycINFO for studies published between 1995 and 2013. Results were described separately for different outcomes (marijuana vs. other illicit drugs) and intervention types (universal, selective, and indicated prevention). Meta-analyses were performed when data were sufficient (e.g., marijuana and other illicit drug initiation in universal samples), using random effect models. Otherwise, we provided narrative reviews (e.g., regarding selective and indicated prevention). Thirty-nine papers describing 22 RCTs were eligible for inclusion. Universal family interventions targeting parent-child dyads are likely to be effective in preventing (OR 0.72; 95 % CI 0.56, 0.94) and reducing adolescent marijuana use, but not in preventing other illicit drugs (OR 0.90; 95 % CI 0.60, 1.34). Among high-risk groups, there is no clear evidence for the effectiveness of family interventions in preventing and reducing illicit drug use and drug disorders. The three small RCTs among substance-(ab)using adolescents gave some indication that programs might reduce the frequency of illicit drug use. Family interventions targeting parent-child dyads are likely to be effective in preventing and reducing adolescent marijuana use in general populations, but no evidence for other illicit drug use was found. We underline the need to strengthen the evidence base with more trials, especially among at-risk populations.
    Clinical Child and Family Psychology Review 05/2015; 18(3). DOI:10.1007/s10567-015-0185-7 · 4.75 Impact Factor
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    • "While cannabis use is common among Western youth, early onset and frequent use are associated with increased risks of low school performance (Fergusson et al., 2007) and mental problems, e.g., depression (de Graaf et al., 2010) and psychosis (Schubart et al., 2010). Approximately 30% of Dutch adolescents have used cannabis at the age of 16 (Verdurmen et al., 2012a), which is comparable to the average of European 15–16 year olds (29%; Hibell et al., 2012). "
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    ABSTRACT: To investigate general and cannabis-specific parenting practices in relation to adolescent cannabis and other illicit drug use. Data were derived from the Dutch National School Survey on Substance Use among students (N=3209; aged 12-16 years) and one of their parents in 2011. Logistic regression analyses revealed that 1) parental cannabis use was significantly related to more adolescent lifetime and recent cannabis use, and 2) restrictive cannabis-specific parental rules were associated with less adolescent recent cannabis and lifetime use of other illicit drugs, even when controlled for sociodemographic factors, general parenting, adolescent tobacco use, and tobacco-specific parenting. In addition, no significant interaction was observed between parental cannabis use and cannabis-specific rules in their relation to adolescent cannabis and other illicit drug use, indicating that cannabis rules are evenly associated with adolescent drug use for families with and without parental cannabis experience. In addition to general parenting practices, restrictive cannabis-specific rules are related to lower adolescent cannabis and other illicit drug rates. Parents who ever used cannabis have children with a higher prevalence of cannabis use. However, their restrictive cannabis-specific rules are equally related to a lower chance of adolescent cannabis use. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
    Drug and Alcohol Dependence 11/2014; 147. DOI:10.1016/j.drugalcdep.2014.11.014 · 3.42 Impact Factor
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    • "With respect to psychopathology and psychological problems, associations often appear to be limited to specific aspects of cannabis use, such as an earlier starting age or a longer duration of use. Quantity or frequency of use also appears to play a key role, as well as preexisting vulnerability to psychological problems or psychopathology (Lynskey, Vink, & Boomsma, 2006; Schubart et al., 2011; Swift et al., 2012). With respect to cognitive outcomes, similar factors have been investigated (Nordstrom & Hart, 2006; Solowij & Battisti, 2008), but most attention has been given to acute versus nonacute effects of cannabis (e.g., Bossong, Jager, Bhattacharyya, & Allen, 2014; Crean, Crane, & Mason, 2011) and to defining the cognitive profile of cannabis users and whether a profile could be established that is specific for cannabis use (as opposed to a more generic profile associated with use of other substances as well; e.g., Griffith-Lendering, Huijbregts, Vollebergh, & Swaab, 2012; Morgan et al., 2012; Stacy & Wiers, 2010; Verdejo-Garcia et al., 2008). "
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    ABSTRACT: Background: Cannabis use has been associated with neurocognitive impairments and psychopathology. The strength of such associations does however appear to depend on many different factors, such as duration and intensity of use, but also differential susceptibility due to genetic make-up and environmental influences. The present study investigated whether specific cognitive weaknesses moderated associations between cannabis use and psychoneuroticism, which may be considered one of the "softer" expressions of an extended psychosis phenotype. Method: One hundred and fifty (150) young adults (mean age: 24.7 years, SD: 3.7), mostly college students, performed three computerized neuropsychological tasks: a relatively easy social perception task (Face Recognition), a more complex social perception task combining emotion recognition and executive functioning (Matching Facial Emotions), and a more complex task requiring sustained attention and executive functioning (Sustained Attention-Dots). Participants self-reported on the extent to which they experienced psychological problems using the Symptom Checklist-90 (SCL-90). The SCL-90 total score (psychoneuroticism) was used as dependent variable in analyses of variance. Results: Frequent and current cannabis users performed more poorly than nonusers on the three tasks. They also reported more psychoneuroticism than nonusers whether they were classified according to their lifetime use, their use during the past 12 months, or use during the past 4 weeks. Moderate and former users did not differ from nonusers. Relatively poor performance on the Matching Facial Emotions task, as opposed to performance on the Face Recognition and Sustained Attention tasks, augmented levels of experienced psychoneuroticism among frequent and current cannabis users. Conclusions: Relatively poor cognitive abilities appear to represent increased vulnerability to effects of frequent and current cannabis use on affective mental health, even among highly educated individuals. There seems to be some specificity as to which (combinations of) neurocognitive abilities may be most indicative, as moderating effects were only observed when participants had relatively poor complex social perception ability.
    Journal of Clinical and Experimental Neuropsychology 08/2014; 36(8):1-12. DOI:10.1080/13803395.2014.943694 · 2.08 Impact Factor
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