BACKGROUND Despite mounting evidence that use of and dependence on alcohol and cannabis are influenced by heritable factors, the extent to which heritable influences on these phenotypes overlap across the 2 substances has only rarely been explored. In the current study, we quantified cross-substance overlap in sources of variance and estimated the degree to which within-substance associations b...

Introduction The proliferation of electronic devices, such as vape-pens, has provided alternative means for cannabis use. Research has found cannabis-vaping (i.e., vape-pen use) is associated with lower perceived risks and higher cannabis use. Knowledge of these products may increase likelihood of subsequent use. As policies for cannabis shift, beliefs that peers and family approve of this subs...

BACKGROUND Previous research has reported both a moderate degree of comorbidity between cannabis dependence and major depressive disorder (MDD) and that early-onset cannabis use is associated with increased risks for MDD. OBJECTIVE To examine whether associations between both lifetime cannabis dependence and early cannabis use and measures of MDD, suicidal ideation, and suicide attempt persis...

OBJECTIVE To examine the reasons for cannabis use among individuals with psychotic disorders. METHOD Forty-nine people with psychotic disorders in treatment with community health centres in Northern Sydney were interviewed to collect information about their experience of antipsychotic side-effects and their influence on cannabis use. Other information collected on cannabis use included: amoun...

This paper reviews research examining the link between cannabis use and educational attainment among youth. Cross-sectional studies have revealed significant associations between cannabis use and a range of measures of educational performance including lower grade point average, less satisfaction with school, negative attitudes to school, increased rates of school absenteeism and poor school pe...

Cite this as: BMJ 2010;340:c1571 doi: 10.1136/bmj.c1571 About a third of adults in the UK have tried cannabis, and 2.5 million people, mostly 16-29 year olds, have used it in the past year. Although most people who smoke cannabis will develop neither severe mental health problems nor dependence, regular use of cannabis may be associated with a range of health, emotional, behavioural, social, an...

Although cannabis is the most commonly used illicit drug, duration of cannabis use is typically short, with many of those who initiate cannabis use ceasing use by their late twenties. In this paper we analyze data from a volunteer Australian cohort of 6265 male and female twins to examine whether the duration of cannabis use is an informative phenotype for future genetic analyses. Genetic model...

Chronic cannabis use has been associated with neurocognitive deficits, alterations in brain structure and function, and with psychosis. This study investigated the effects of chronic cannabis use on P50 sensory-gating in regular users, and explored the association between sensory gating, cannabis use history and the development of psychotic-like symptoms. Twenty controls and 21 regular cannabis...

Psychosis is one of the most serious among the adverse effects associated with cannabis use. The association between cannabis use and psychosis has been variously explored in a series of recent meta-analyses. The results of these meta-analyses show that persons who develop psychosis experience onset of psychosis about 2-3 years earlier if they are cannabis users; this effect is not observed wit...

INTRODUCTION AND AIMS Recent years have witnessed increased attention to how cannabis use impacts the use of other psychoactive substances. The present study examines the use of cannabis as a substitute for alcohol, illicit substances and prescription drugs among 473 adults who use cannabis for therapeutic purposes. DESIGN AND METHODS The Cannabis Access for Medical Purposes Survey is a 414-q...