Solja Niemelä

• MD PhD Professor (Addiction Medicine)
• Professor (Full) at University of Turku

Purpose of Review This systematic review examines the association between co-occurring psychotic disorders and Opioid Agonist Therapy (OAT) outcomes in Opioid Use Disorder (OUD). Recent Findings We searched eight databases and reference lists up to March 20, 2024, for observational studies comparing OAT outcomes in patients with OUD with and witho...

Background and Aims Substance‐induced psychoses (SIP) have the potential to relapse and convert into schizophrenia‐spectrum disorders. However, risk factors associated with SIP relapse remain unknown. The aim of this study was to measure the incidence and risk of SIP relapse and associating risk factors. Design, setting and participants Population...

Schizophrenia (SZ), schizoaffective disorder (SZA), bipolar disorder (BD), and psychotic depression (PD) are associated with premature death due to preventable general medical comorbidities (GMCs). The interaction between psychosis, risk factors, and GMCs is complex and should be elucidated. More research particularly among those with SZA or PD is...

• Kannabiksen käyttö lisääntyy, ja sitä käyttäviä potilaita kohdataan enenevässä määrin myös terveydenhuollossa. • Erityisesti korkea THC-pitoisuus liittyy kannabiksen käytön yhteydessä ilmeneviin psykiatrisiin haittoihin. • Kannabiksen runsas käyttö on erityisesti nuorilla yhteydessä kielteisiin kognitiovaikutuksiin. • Kannabiksen käyttö raskau...

Background A nationwide register-based cohort study from Finland including 48 124 incident benzodiazepines and related drug (BZDR) users aged 18–65 years who initiated use in 2006 and were not dispensed BZDRs during 2004–2005. The follow-up was 5 years or until death, whichever occurred first. Aims To investigate sociodemographic and clinical fact...

The ICD-11 was introduced in January 2022. In chapter 6, “Mental, behavioral and neurodevelopmental disorders” we find the section “Disorders due to substance use and addictive behaviors” (section 6C4). Changes from the ICD-10 in this section include broadening the categories of harmful use and dependence, including more types of substances, and th...

Substance-induced psychosis (SIP) is characterized by both substance use and a psychotic state, and it is assumed that the first causes the latter. In ICD-10 the diagnosis is categorized as and grouped together with substance use disorders, and to a large extent also treated as such in the health care system. Though criticism of the diagnostic cons...

Background The aim of the current study was to assess the accuracy of expert predictions, which were derived using a Delphi panel foresight study between 2009 and 2011, on a variety of drug-related topics in Finland in 2020. Methods The material used to evaluate the accuracy of the predictions consists of published reports on statistics, survey re...

Background Benzodiazepines and related drugs (BZDRs) are widely used in the treatment of anxiety and sleep disorders, but cognitive adverse effects have been reported in long-term use, and these may increase the risk of labor market marginalization (LMM). The aim of this study was to investigate whether the risk of LMM is associated with new long-t...

Background and Hypothesis There is a paucity of research on treatment outcomes of patients with psychosis and cannabis use disorder (CUD). We aimed to compare the effectiveness of antipsychotics in reducing the risk of hospitalization in patients with first-episode psychosis (FEP) and co-occurring CUD. Study Design We utilized a nationwide Swedish...

Background Heavy alcohol and cannabis use during adolescence have been previously described as risk factors not only for morbidity in adulthood, but also social problems including adversities in educational attainment. Attempts to consider overlapping risk factors and confounders for these associations are needed. Methods Using weighted multivaria...

Päihteiden käyttöhäiriöt ovat vangeilla hyvin yleisiä. Elinaikainen päihdehäiriö todettiin 87 prosentilla. Esiintyvyys oli hieman noussut edelliseen vankitutkimukseen verrattuna. Ongelmallinen alkoholin käyttö painottuu vanhempiin ikäryhmiin, kun taas nuoremmilla yleisimpiä olivat huumeongelmat. Noin joka toinen vanki kertoi käyttäneensä amfetamiin...

Background The aim of the current study was to assess the accuracy of expert predictions, which were derived using a Delphi panel foresight study in 2010, on a variety of drug-related topics in Finland in 2020. Methods The material used to evaluate the accuracy of the predictions consists of published reports on statistics, survey results, officia...

Background The aim of this study was to assess the associations between cannabis use and frequency of alcohol intoxication in adolescence with the risk of traumatic brain injury and craniofacial fractures in early adulthood. Hypothesis was that using alcohol and cannabis in adolescence could increase the risk for head traumas. Methods Data from th...

New psychoactive substances (NPS) are a group of substances that mimic established drugs, e.g., cannabinoids, stimulants, and opioids. NPS use has been associated with psychotic-like experiences, but current research is limited. This study focused on NPS use and psychotic-like experiences in persons attending substance use services in South-West Fi...

Background: Externalizing symptoms are associated with risk of future substance use disorder (SUD). Few longitudinal studies exist using general population-based samples which assess the spectrum of attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) symptoms. Aims/objectives: We aimed to study the association...

Background Substance use and sleep problems are common in patients with psychotic disorders, but their associations in these patients have not been evaluated. Our aim was to investigate associations between substance use and sleep problems in a large nationwide cohort of patients with a psychotic disorder. Study design This study is part of the Fi...

Objective: We aimed to assess the predictive associations of age at first drink (AFD), age at first intoxication (AFI), frequency of intoxication, and self-reported alcohol tolerance at age 15-16 to self-harm requiring medical attention or suicide death by age 33. Method: In an ongoing follow-up study, the Northern Finland Birth Cohort 1986, a t...

Purpose of Review Observational studies assessing the association of cannabis use with subsequent intentional self-injury have reported mixed findings. Longitudinal studies examining the association of cannabis use with subsequent suicide death are notably rare. Our objective was to review longitudinal studies examining cannabis use and subsequent...

Introduction: Alcohol, tobacco and coffee are commonly used substances and use in adolescence has previously been linked to mood disorders. However, few large prospective studies have investigated adolescent use in relation to mental health outcomes in adulthood. The main aim of this study was to examine the prospective associations between alcoho...

Introduction Off-label use of antipsychotics has increased in many countries. In adult populations antipsychotics off-label prescriptions varied from 40 to 75% of all AP users. Objectives To examine the off-label prescribing practices and experiences of antipsychotic medication in Finland. Methods An electronic questionnaire on physicians’ prescr...

Background Substance-induced psychosis (SIP) is a serious condition and may predispose for schizophrenia. We know too little about SIP incidence over time and across countries, including substance-specific SIPs. We estimated annual incidence rate of SIP in Denmark, Norway, and Sweden according to substance, age, gender, and socioeconomic background...

Background Overdoses and poisonings are among the most common causes of death in young adults. Adolescent problem drinking has been associated with psychiatric morbidity in young adulthood as well as with elevated risk for suicide attempts. There is limited knowledge on adolescent alcohol use as a risk factor for alcohol and/or drug overdoses in la...

Background Longitudinal studies examining the effect of cannabis exposure (CE) on the prognosis of adolescents with psychotic-like experiences (PLEs) are scarce. We examined trajectories of mental health in adolescents with PLEs and cannabis exposure. Methods The Northern Finland Birth Cohort 1986 (n = 6552) with linkage to nationwide register dat...

Introduction Peer victimization and aggression in adolescence are associated with later mental health morbidity. However, studies examining this association have not controlled for adolescent substance use. We aimed to study the associations between peer victimization, peer aggression, and mental disorders in adulthood, adjusting for substance use...

Aims Benzodiazepines and related drugs (BZDR) are often used longer than generally recommended. The aim is to study patterns of use among migrant and Finnish-born users of BZDR, and to identify factors that are associated with long-term use and BZDR polytherapy. Methods This register-based study includes a nationwide sample of migrants ( n=8729) a...

Background: There is a paucity of knowledge regarding the association of alcohol use with overall survival (OS) of patients with head and neck squamous cell carcinoma (HNSCC). Methods: All 1033 patients treated for new HNSCC in Southwest Finland regional referral center of Turku University Hospital in 2005-2015. Cox regression analysis was used....

Background: Diagnosis of attention deficit hyperactive disorder (ADHD) has been associated with increased risk of mortality in large register samples. However, there is less known about the association between symptoms of ADHD in adolescents and risk of mortality in general population samples. Methods: The Northern Finland Birth Cohort 1986 (n =...

Background Use of antipsychotics (APs) has increased in Europe. Main reason for this is off label use, most commonly the use of quetiapine for insomnia and anxiety. However, there is lack of studies analysing benefits and harms of APs in these conditions. APs have shown efficacy in the treatment of anxiety, but long term follow-ups are rare. Only t...

Background and aims: There are few longitudinal studies assessing the association of cannabis use and subsequent onset of bipolar disorder. We aimed to measure the association between early cannabis exposure and subsequent bipolar disorder. Design, setting, and participants: Observational study linking a sample from the Northern Finland Birth Co...

Background: To study the associations between maternal smoking during pregnancy and paternal smoking before pregnancy and adult offspring psychiatric disorders. Methods: Prospective general population cohort study in Northern Finland, with people from the Northern Finland Birth Cohort 1986: 7259 subjects (77% of the original sample). Data on par...

Objective: Longitudinal studies examining the association between adolescent cannabis use and self-harm are rare, heterogenous and mixed in their conclusions. We study this association utilizing a large general population-based sample with prospective data. Methods: The Northern Finland Birth Cohort 1986 (n= 6582) with linkage to nationwide regi...

The purpose of this study was to explore the association of cognition with hazardous drinking Polygenic Scores (PGS) in 2649 schizophrenia, 558 schizoaffective disorder, and 1125 bipolar disorder patients in Finland. Hazardous drinking PGS was computed using the LDPred program. Participants performed two computerized tasks from the Cambridge Automa...

The purpose of this study was to explore the association of cognition with hazardous drinking and alcohol-related disorder in persons with bipolar disorder (BD). The study population included 1268 persons from Finland with bipolar disorder. Alcohol use was assessed through hazardous drinking and alcohol-related disorder including alcohol use disord...

Objective We examined the association between the non-medical use of prescription drugs (NMUPD) and self-reported health problems due to the use of prescription drugs (hypnotics, sedatives, or strong painkillers), and whether it differed by social background among the general Finnish population. Methods Population-based (aged 15–69) Drug Surveys co...

Background Since the early 2000’s, buprenorphine has been the most used street opioid in Finland. Buprenorphine-naloxone combination drug was originally introduced due to its lower abuse potential when injected compared to monobuprenorphine. Currently, buprenorphine-naloxone combination drug is the most used drug in Finnish opioid agonist treatment...

Background Cannabis use has been associated with increased risk of psychiatric disorders. However, associations between adolescent cannabis use, depression and anxiety disorders are inconsistently reported in longitudinal samples. Aims To study associations of adolescent cannabis use with depression and anxiety disorders. Method We used data from...

The purpose of this study was to explore the association of cognition with hazardous drinking and alcohol related disorder in persons with bipolar disorder (BD). The study population included 1,268 persons from Finland with bipolar disorder. Alcohol use was assessed through hazardous drinking and alcohol related disorder including alcohol use disor...

The purpose of this study was to explore the association between cognition and hazardous drinking and alcohol use disorder in schizophrenia and schizoaffective disorder. Cognition is more or less compromised in schizophrenia, and schizoaffective disorder and alcohol use might aggravate this phenomenon. The study population included 3362 individuals...

Purpose of the study was to explore the association of cognition with hazardous drinking, binge drinking and alcohol use disorder in schizophrenia and schizoaffective disorder. Cognitive deficits are common in schizophrenia. Alcohol might be associated with additional cognitive impairment in schizophrenia patients. The study population included 336...

Objective Early onset of alcohol use is associated with an increased risk of substance use disorders (SUD), but few studies have examined associations with other psychiatric disorders. Our aim was to study the association between the age of first alcohol intoxication (AFI) and the risk of psychiatric disorders in a Finnish general population sample...

Aim The Alcohol Use Disorders Identification Test (AUDIT) has been validated for use with adolescents to screen their harmful alcohol consumption. How well AUDIT or its derivative consumption version AUDIT-C predicts the development of problematic alcohol use among adolescents remains unknown. The aim of our study was to examine the predictive capa...

Background: More information on the health-related repercussions of age at onset of adolescent drinking is needed. The aim of this study was to examine the associations between self-reported age at first drink and age at first alcohol intoxication with the risk of death by age 30. Methods: The sample (n = 6564; 49.1% males) included all particip...

Author’s reply - Volume 217 Issue 2 - Antti Mustonen, Solja Niemelä, Tanja Nordström, Graham K. Murray, Erika Jääskeläinen, Jouko Miettunen

Purpose Long-term prospective studies evaluating the health burden that is consequent to adolescent drinking are needed. The aim of this study was to examine the predictive associations between self-reported alcohol tolerance and frequent intoxication at age 15–16 years and the risk of death by age 33 years. Methods A sample (n = 6,615; 49.3% male...

Background Association between smoking with both ADHD(1) and psychosis(2) has been explained by self-medication of ADHD and psychotic symptoms with nicotine use(3). Persons with psychosis also share impairments with persons with ADHD: e.g. inattention is a feature of both of these disorders(3). Aim of this study was to investigate the association b...

Background Recent studies indicate that adolescent cannabis use (1) and cigarette smoking (2) increase the risk for psychosis. However, less is known about symptom profile associated with cannabis use and cigarette smoking prior to the psychotic episodes. Our aim was to study the associations between daily smoking, life-time cannabis use, and psych...

Purpose Mental health and substance use disorders are notable contributors to the global total burden of disease. On a population level, co-occurring mental health and substance use problems are estimated to account for 2–4%. In clinical samples, estimate is even higher. The aim of this study was to examine changes in recognized mental health probl...

Comorbidity of substance use with affective symptoms and suicidality has been well documented in the general population. However, population-based migrant studies about this association are scarce. We examined the association of affective symptoms and suicidal ideation with binge drinking, daily smoking, and lifetime cannabis use among Russian, Som...

Background Long-term excessive use of alcohol leads to severe complications, which often require treatment in an intensive care unit (ICU). The aim of this study was to report on the associations between alcohol-related health problems and treatment profile, as well as 1-year mortality among patients with nontrauma-related ICU admissions. Methods...

Background and aims: The associations between traumatic events, substance use and perceived discrimination have been rarely studied among migrants in host countries. We examined whether pre-migration potentially traumatic experiences (PTEs) or perceived discrimination (PD) are associated with substance use among migrants with voluntary (Russians)...

Alterations induced by prenatal exposure to nicotine have been observed in experimental (rodent) studies. While numerous developmental outcomes have been associated with prenatal exposure to maternal cigarette smoking (PEMCS) in humans, the possible relation with brain structure is less clear. Here we sought to elucidate the relation between PEMCS...

Aims: To assess the associations of intoxication frequency and number of drinks needed to become intoxicated in mid-adolescence with onset of psychiatric disorders in early adulthood. Design, setting and participants: Prospective cohort study in Northern Finland, with people from the Northern Finland Birth Cohort 1986 who self-reported adolescen...

BACKGROUND. Health care services have a key role in the prevention, identification and treatment of alcohol problems. Prevalence estimates for risky drinking have not been reported based on the Current Care Guidelines (2015) for the treatment of patients with alcohol problems. METHODS. General population sample of 15 to 79 year-old people in Finlan...

Cannabis use is the most common form of illicit adolescent substance use. Adolescence is a vulnerable neurodevelopmental period, during which many brain maturation processes take place. Substance use during this critical period may disrupt these processes. Adolescent cannabis use has been associated with dysregulation of the endocannabinoid system...

Using data from the Northern Finland Birth Cohort 1986, we aim to investigate the prospective association between self-reported frequency of intoxication and alcohol tolerance, determined by self-reported number of drinks required to experience intoxication, at age 15to 16 years and psychiatric diagnoses by the age of 29 – 30 years. Information on...

There has been emerging evidence of an association between tobacco smoking and schizophrenia spectrum disorders (SSD). Two meta-analyses have reported that people who smoke tobacco have an ~2-fold increased risk of incident schizophrenia or psychosis, even after adjusting for confounding factors. This study aimed to critically appraise the research...

Background Temperament is theorized to be an important factor contributing to the development of alcohol use disorder, but longitudinal studies on how temperament is related to alcohol use among general population in mid‐life are scarce. Our aims were to investigate potentially reciprocal associations between temperament and changes in alcohol use...

Background: Cross-sectional studies have suggested inhalant use is associated with psychosis. This association was examined in a longitudinal study accounting for other substance use and potential confounders. Methods: We used a prospective sample (N = 6542) from the Northern Finland Birth Cohort 1986. Self-report questionnaires on substance use...

Abstract Background Substance use is a well-known public health problem, but population-based research on migrants’ substance use in Europe is limited. Factors related to the cultural background and current life situation might influence substance use among migrants. Here, the prevalence of substance use in Russian, Somali and Kurdish migrants in F...

Background: The Alcohol Use Disorders Identification Test (AUDIT) is commonly used in adults to screen for harmful alcohol consumption but few studies exist on its use among adolescents. Our aim was to validate the AUDIT and its derivative consumption questionnaire (AUDIT-C) as screening instruments for the detection of problem use of alcohol in a...

Background: Association of cannabis use and the risk of psychosis has been studied extensively but the temporal order still remains controversial.

Background The association between cannabis use and the risk of psychosis has been studied extensively but the temporal order still remains controversial. Aims To examine the association between cannabis use in adolescence and the risk of psychosis after adjustment for prodromal symptoms and other potential confounders. Method The sample (n = 653...

Objective: Daily smoking has been associated with a greater risk of psychosis. However, we are still lacking studies to adjust for baseline psychotic experiences and other substance use. We examined associations between daily smoking and psychosis risk in a 15-year follow-up while accounting for these covariates in a prospective sample (N = 6081)...

Objective: Daily smoking has been associated with greater risk of psychosis. However, we are still lacking studies to adjust for baseline psychotic experiences and other substance use. We examined associations between daily smoking and psychosis risk in a 15-year follow-up while accounting for these covariates in a prospective sample (N=6081) from...

Oral presentation

A number of structural properties of white matter can be assessed in vivo using multimodal magnetic resonance imaging (MRI). We measured profiles of R1 and R2 relaxation rates, myelin water fraction (MWF) and diffusion tensor measures (fractional anisotropy [FA], mean diffusivity [MD]) across the mid-sagittal section of the corpus callosum in two s...

Aims: To evaluate the influences of alcohol consumption frequency and binge drinking on changes in the body composition, lifestyle habits and physical fitness of healthy young men during military service. Methods: A population-based study of men performing their military service in the Sodankylä Jaeger Brigade, Finland in 2005. Body composition,...

Background The association between prenatal exposure to maternal cigarette smoking (PEMCS) and adult cognition is debated, including if there are differences according to sex. We aimed to determine if there are associations between PEMCS and cognition in early adulthood in men and women and examine if observed associations were mediated by adolesce...

Background Alcohol use during pregnancy leads to detrimental effects on fetal development. As self-reports by mothers are known to be unreliable for assessing prenatal alcohol exposure, there is a need for sensitive and specific biomarkers for identifying those at risk for alcohol-affected offspring. Methods We measured serum gamma-glutamyl transfe...

Aims: To study the predictive associations between maternal smoking and the impact of quitting smoking during pregnancy and offspring daily smoking at age 15-16 years. Design: The Northern Finland Birth Cohort 1986 (NFBC86) includes 99% of all births in the region and has an ongoing follow-up. Data were collected using questionnaires at 24th ges...

Background Fetal alcohol syndrome (FAS) is a well‐known consequence of prenatal alcohol exposure. However, women tend to deny or underreport their alcohol use during pregnancy. The aim of this study was to explore the usability of various alcohol biomarkers for FAS screening in a data set without information on self‐reported alcohol use. Methods A...

Objective: Cigarette smoking during pregnancy is a major public health problem leading to adverse health outcomes and neurodevelopmental abnormalities among offspring. Its prevalence in the United States and Europe is 12%-25%. This study examined the relationship between prenatal nicotine exposure (cotinine level) in archived maternal sera and sch...

Introduction Although substance use is a well-known public health risk factor, European population-based studies reporting the substance use among adult migrant populations are scarce. Objectives We aim to: (1) determine the prevalence of alcohol use, cigarette smoking and consumption cannabis and intravenous drugs in Russian, Somali and Kurdish m...

Background Longitudinal studies on how temperament is related to alcohol use in general population are scarce. Objectives Finding relations with temperament and problematic alcohol use using prospective birth cohort data. Aims To investigate trends in self-reported alcohol consumption in adulthood. Methods In the Northern Finland Birth Cohort 19...

Introduction Prenatal smoking exposure is one of the most common insults during the fetal period prevalence varying from 5 to 19% in the European countries [1]. Objectives Prenatal smoking exposure increases the risk of psychiatric morbidity in the offspring, externalizing disorders in particular. However, less is known whether maternal smoking du...

Objective: To describe changes in alcohol use in relation to employment, education and relationship statuses in a general population sample in early midlife using prospective birth cohort data. Materials and methods: In the Northern Finland Birth Cohort 1966 (N=5621) alcohol use was studied in participants at two time points: ages 31 and 46. The...

Introduction Recent studies have shown that cannabis use acts as a specific risk factor provoking the onset of psychosis in vulnerable individuals. Association of adolescent cannabis use and psychosis risk was studied after adjustment with prodromal symptoms. Objectives To assess possible causality between cannabis use and the risk of psychosis....

Background Longitudinal alcohol consumption in early adulthood has been studied, but reports from later adulthood are scarce. Objectives Finding longitudinal trends in alcohol consumption using prospective birth cohort data. Aims To investigate trends in self-reported alcohol consumption in adulthood. Methods In the Northern Finland Birth Cohort...

Corpus callosum (CC) is the main interhemispheric fiber tract in the human brain, consisting of about 200 million axons. Heterogeneity of its fiber composition suggests that cortical regions differ in the type of channels carrying information between their left-right homologues. The microstructure of CC, as of all white matter (WM), can be characte...

The discounting of delayed rewards, also known as temporal or delay discounting, is intrinsic to everyday decisions and can be impaired in pathological states such as addiction disorders. Preclinical and human studies suggest a role for dopaminergic function in temporal discounting but this relationship has not yet been verified using molecular ima...

Background: Impulse control disorders can have serious adverse consequences to the life of a patient with Parkinson's disease. Although impulse control disorders are common, a possible psychiatric comorbidity has not been fully characterized. Objective: The aim of this study was to investigate the psychiatric symptoms exhibited by Parkinson's disea...

Properly conducted pharmacological therapy is expected to improve the prognosis of both the psychic disturbance and the substance abuse problem. Considering the extent of the problem there is, however, relatively little evidence-based knowledge of pharmacological therapy of an addiction psychiatric patient. Separation of psychiatric therapy from ad...

Objective. To study predictive associations between psychosocial factors at age 8 and becoming a mother under the age of 20. Design: Prospective follow-up study. Setting: Finland. Population. 2867 girls born in 1981. Methods. Information on family background and psychiatric symptoms was collected at age 8. The associations between these factors and...

The present study examines the 10-year time-trend changes of adolescent psychiatric symptoms, smoking and alcohol use. Representative population-based samples with same methods at two time-points, same age range and with 10-year period between the time points were gathered in Finland to investigate secular changes in adolescents' emotional and beha...

Impulse control disorders (ICDs) occur frequently in PD patients. To investigate the possible involvement of the mesostriatal and mesolimbic monoaminergic function in ICDs associated with PD, we examined patients with (n = 10) and without (n = 10) ICDs using the brain [(18) F]fluorodopa PET. Patients with ICDs (e.g., pathological gambling, hypersex...

Background:Impulse control disorders (ICDs) occur frequently in PD patients. Methods:To investigate the possible involvement of the mesostriatal and mesolimbic monoaminergic function in ICDs associated with PD, we examined patients with (n = 10) and without (n = 10) ICDs using the brain [18F]fluorodopa PET. Results:Patients with ICDs (e.g., patholo...