BACKGROUND Cannabis is the most widely consumed illicit substance in America, with increasing rates of use. Some theorists tend to link frequency of use with cannabis dependence. Nevertheless, fewer than half of daily cannabis users meet DSM-IV-TR criteria for cannabis dependence. This study seeks to determine whether the negative aspects associated with cannabis use can be explained by a proxy...

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...

OBJECTIVES To determine incidence and patterns of natural course of cannabis use and disorders as well as cohort effects in a community sample of adolescents and young adults. METHOD Cumulative incidence and patterns of cannabis use and disorders were examined in a prospective longitudinal design (mean follow-up period=42 months) in a representative sample (N=2446) aged 14-24 years at the out...

Recent reports show that fewer adolescents believe that regular cannabis use is harmful to health. Concomitantly, adolescents are initiating cannabis use at younger ages, and more adolescents are using cannabis on a daily basis. The purpose of the present study was to test the association between persistent cannabis use and neuropsychological decline and determine whether decline is concentrate...

BACKGROUND Cannabis exposure, particularly heavy cannabis use, has been associated with neuroanatomical alterations in regions rich with cannabinoid receptors such as the hippocampus in some but not in other (mainly cross-sectional) studies. However, it remains unclear whether continued heavy cannabis use alters hippocampal volume, and whether an earlier age of onset and/or a higher dosage exac...

XI Abbreviations XVIII Publications and Submissions XX Chapter 1 Cannabis: a review of use, abuse and dependence 1 1.1. A brief history of cannabis use 1 1.2. Current use of cannabis 4 1.3. Recent advances in cannabinoid science 7 1.4. Cannabis dependence in humans 11 1.5. Why do people become dependent on cannabis? 15 1.5.1. The cannabis withdrawal syndrome 16 1.5.2. The role of cannabis withd...

To estimate the patterns and prevalence of cannabis use among patients with multiple sclerosis (MS), 220 patients were surveyed in Halifax, Nova Scotia. Seventy-two subjects (36%) reported ever having used cannabis for any purpose; 29 respondents (14%) reported continuing use of cannabis for symptom treatment. Medical cannabis use was associated with male gender, tobacco use, and recreational c...

OBJECTIVES Determine the prevalence of drug use in injured drivers and identify associated demographic factors and crash characteristics. DESIGN Prospective cross-sectional study. SETTING Seven trauma centres in British Columbia, Canada (2010-2012). PARTICIPANTS Automobile drivers who had blood obtained within 6 h of a crash. MAIN OUTCOME MEASURES We analysed blood for cannabis, alcohol...

Tetrahydrocannabinol (THC) has been the primary focus of cannabis research since 1964, when Raphael Mechoulam isolated and synthesized it. More recently, the synergistic contributions of cannabidiol to cannabis pharmacology and analgesia have been scientifically demonstrated. Other phytocannabinoids, including tetrahydrocannabivarin, cannabigerol and cannabichromene, exert additional effects of...

M ultifocal angiopathy associated with cannabis consumption is an uncommon cause of ischemic stroke in young individuals. The main radiological characteristics include the presence of multifocal intracranial stenosis and the reversibility of vasoconstriction after cannabis withdrawal. 1–3 Cannabis use has been linked recently to other arterial complications, including myocardial infarction (str...