This study investigates whether impaired young adults with attention-deficit/hyperactivity disorder symptoms always have a childhood-onset disorder in a population-based longitudinal study.
This study investigates childhood risk factors and functioning in young adults with persistent, remitted, and late-onset ADHD.
This cohort and co-relative study aims to clarify the degree to which the excess mortality associated with alcohol use disorders arises from (1) the predispositions of the person who develops AUD (and which would likely be shared by close relatives) and (2) a direct result of AUD itself.
This review article summarizes what is known about the effects of cannabis use on human behavior, including cognition, motivation, and psychosis.
This Finnish national birth cohort study assesses the association of childhood bullying and/or exposure to bullying with subsequent psychiatric outcomes and diagnoses made during adolescence or adulthood.
This cross-sectional study demonstrates that psychiatric comorbidities are common among individuals with Tourette syndrome and that most comorbidities begin early in life.
A number of studies have found that the use of cannabis and other psychoactive substances is associated with an earlier onset of psychotic illness.
To establish the extent to which use of cannabis, alcohol, and other psychoactive substances affects the age at onset of psychosis by meta-analysis.
Peer-reviewed publications in English reporting age at onset of psychotic illness in substance-using and non–substance-using groups were located using searches of CINAHL, EMBASE, MEDLINE, PsycINFO, and ISI Web of Science.
Studies in English comparing the age at onset of psychosis in cohorts of patients who use substances with age at onset of psychosis in non–substance-using patients. The searches yielded 443 articles, from which 83 studies met the inclusion criteria.
Information on study design, study population, and effect size were extracted independently by 2 of us.
Meta-analysis found that the age at onset of psychosis for cannabis users was 2.70 years younger (standardized mean difference = −0.414) than for nonusers; for those with broadly defined substance use, the age at onset of psychosis was 2.00 years younger (standardized mean difference = −0.315) than for nonusers. Alcohol use was not associated with a significantly earlier age at onset of psychosis. Differences in the proportion of cannabis users in the substance-using group made a significant contribution to the heterogeneity in the effect sizes between studies, confirming an association between cannabis use and earlier mean age at onset of psychotic illness.
The results of meta-analysis provide evidence for a relationship between cannabis use and earlier onset of psychotic illness, and they support the hypothesis that cannabis use plays a causal role in the development of psychosis in some patients. The results suggest the need for renewed warnings about the potentially harmful effects of cannabis.