The genetic and environmental associations between cannabis use and annual income

Background: Cannabis use is linked to a number of maladaptive psychiatric and psychosocial outcomes including reduced income. Although familial aggregation in cannabis use and income can be explained by a combination of... [ view full abstract ]

Background: Cannabis use is linked to a number of maladaptive psychiatric and psychosocial outcomes including reduced income. Although familial aggregation in cannabis use and income can be explained by a combination of genetic and shared environmental factors, the biometrical genetic association between cannabis and income have not been explored. Aim: What are genetic and environmental associations between cannabis use and annual income? Methods: Subjects were 1,419 twins (µage = 28.2 years) from the Norwegian Institute of Public Health Twin Panel with cannabis and income data. Measures of lifetime cannabis use were obtained in a face-to-face interview in 1999-2004 as part of a population-based study of mental health. This included assessments of lifetime cannabis use and cannabis use disorder based on DSM-IV abuse and dependence criteria, including withdrawal and craving. Annual income from 1993-2014 was obtained from The Income Registry through Statistics Norway. Cannabis and income data were merged based on unique national identification numbers granted to all Norwegians at birth. Results: Multivariate analyses revealed significant genetic and environmental associations between cannabis use and annual income. Discussion: Results and implications to be discussed.