title: Cannabis use and the course and outcome of major depressive disorder: A population based longitudinal study.
abstract: Cannabis use has been reported to affect the course of various psychiatric disorders, however its effect on the course of major depressive disorder (MDD) is not yet clear. We used data from Wave 1 and Wave 2 of the National Epidemiologic survey on Alcohol and Related Conditions (NESARC). Individuals with baseline MDD (N=2,348) were included in the study. Cannabis users without a Cannabis Use Disorder (CUDs) and individuals with a CUD were compared to nonusers using linear and logistic regression analyses controlling for sociodemographics, psychiatric disorders and substance use disorders at baseline. No differences were found in rates of remission between the groups. Level of cannabis use was associated with significantly more depressive symptoms at follow-up, particularly anhedonia, changes in body weight, insomnia or hypersomnia and psychomotor problems. After adjusting for baseline confounding factors, no associations were found between cannabis use and suicidality, functionality and quality of life. We conclude that many of the associations between cannabis use and a more severe course of MDD do not seem to be attributed to cannabis use itself but to associated sociodemographic and clinical factors. Further longitudinal studies using depression severity indices are required.
authors.affiliation: Ariel University, Ariel, Israel; Lev-Hasharon Medical Center, Pardesiya, Israel. Electronic address: d.y.feingold@gmail.com.
authors.forename: Daniel
authors.initials: D
authors.lastname: Feingold
authors.affiliation: Social and Epidemiological Research Department, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Technische Universität Dresden, Klinische Psychologie & Psychotherapie, Dresden, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rehm
authors.affiliation: Lev-Hasharon Medical Center, Pardesiya, Israel; Social and Epidemiological Research Department, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Shaul
authors.initials: S
authors.lastname: Lev-Ran
mesh_terms: D000328:Adult; D002188:Cannabis / Q000009:adverse effects*; D003865:Major Depressive Disorder / Q000139:chemically induced / Q000523:psychology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology*; D008385:Marijuana Smoking / Q000523:psychology*; D008875:Middle Aged; D011788:Quality of Life; D055815:Young Adult
keywords: Cannabis use Disorder; Course of illness; Depression; Marijuana; Quality of life; Suicidality; Symptoms