Background Cannabis use in young people is common and associated with psychiatric disorders. However, the prospective link between cannabis use and bipolar disorder symptoms has rarely been investigated. The study hypothesis was that adolescent cannabis use is associated with hypomania in early adulthood via several potential etiological pathways. Methods Data were used from the Avon Longitud...

BACKGROUND Because cannabis use is associated with social, physical and psychological problems, it is important to know what causes some individuals to initiate cannabis use and a subset of those to become problematic users. Previous twin studies found evidence for both genetic and environmental influences on vulnerability, but due to considerable variation in the results it is difficult to dra...

BACKGROUND In the present study, we examined the relationship between cannabis involvement and suicidal ideation (SI), plan and attempt, differentiating the latter into planned and unplanned attempt, taking into account other substance involvement and psychopathology. METHODS We used two community-based twin samples from the Australian Twin Registry, including 9583 individuals (58.5% female, ...

AIM To examine the evidence on the association between cannabis and depression and evaluate competing explanations of the association. METHODS A search of Medline, Psychinfo and EMBASE databases was conducted. All references in which the terms 'cannabis', 'marijuana' or 'cannabinoid', and in which the words 'depression/depressive disorder/depressed', 'mood', 'mood disorder' or 'dysthymia' wer...

Cannabis users are more likely to have psychotic experiences (PEs). The degree to which these associations are driven by genetic or environmental influences in adolescence is unknown. This study estimated the genetic and environmental contributions to the relationship between cannabis use and PEs. Specific PEs were measured in a community-based twin sample (4830 16-year-old pairs) using self-re...

AIM To examine possible causal linkages between cannabis use and psychosis using data gathered over the course of a 25-year longitudinal study. DESIGN A 25-year longitudinal study of the health, development and adjustment of a birth cohort of 1265 New Zealand children (635 males, 630 females). SETTING The Christchurch Health and Development Study, a general community sample. PARTICIPANTS ...

OBJECTIVE We aimed to assess whether individuals at ultra high risk (UHR) for psychosis have higher rates of cannabis use and cannabis use disorders (CUDs) than non-UHR individuals and determine whether UHR cannabis users have more severe psychotic experiences than non-users. METHOD We conducted a meta-analysis of studies reporting cannabis use in the UHR group and/or positive or negative sym...

BACKGROUND The relationship between cannabis use and psychosis is still a matter for debate. Accounting for the individual differences in subjective experiences to recreational cannabis use in the general population may hold some clues to the aetiological relationship between cannabis and psychotic symptoms. We hypothesized that schizotypy would account for the individual differences in subject...

Cannabis is one of the oldest and most commonly abused drugs in the world. Recently, tremendous advances have been made in our understanding of the endogenous cannabinoid system with the identification of cannabinoid receptors, cannabinoid receptor antagonists, endogenous neurotransmitters, metabolic enzymes, and reuptake mechanisms. These advances have helped us to elucidate the mechanisms of ...

BACKGROUND A clearer understanding of the basis for the association between cannabis use and psychotic experiences (PEs) is required. Our aim was to examine the extent to which associations between cannabis and cigarette use and PEs are due to confounding. METHOD A cohort study of 1756 adolescents with data on cannabis use, cigarette use and PEs. RESULTS Cannabis use and cigarette use at ag...