Personality disorders and social support in cannabis dependence: A comparison with alcohol dependence

•Compared personality disorders (PD) and social support between cannabis and alcohol dependence.•Cannabis dependence alone had higher rates of most PDs than alcohol dependence alone.•Cannabis dependence alone was associated with lower social support than alcohol dependence alone. Cannabis use disorder (CUD) has been linked to personality disorders (PDs) and interpersonal problems, though these relationships have been understudied. We examined PDs and social support associated with cannabis dependence and how it may be distinguishable from alcohol dependence on these indices in a large representative sample. Method: Data on social support and Diagnostic and Statistical Manual of Mental Disorders-IV substance dependence and PDs were assessed in Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (N > 34,500). Results: Cannabis dependence was associated with higher rates of personality disorders and lower social support. Lifetime cannabis dependence without alcohol dependence was associated with higher rates of all PDs than alcohol dependence without cannabis dependence (with the exception of borderline PD). Cannabis dependence alone was also associated with lower social support than alcohol dependence alone. Limitations: The survey was conducted in 2004–2005 and relied on DSM-IV criteria. Conclusions: These findings highlight a broad range of PDs as well as deficits in social support in cannabis dependence. The potential interrelationships between interpersonal dysfunction and CUD as well as the relevance of PDs to treatment for CUD warrant further research.