A review of Indian research on co-occurring cannabis use disorders & psychiatric disorders

Background & objectives: Cannabis is a widely used illicit drug and its use is often associated with co-occurring psychiatric disorders. This systematic review was aimed to provide information on the published Indian studies on co-occurring cannabis use disorders and psychiatric disorders. Methods: An electronic search of available Indian literature using relevant search terms was carried out in May 2015 and 52 articles in English language published from India were included in the current review. Results: Studies on cannabis and associated psychotic disorders (n=16) chiefly described acute episodes with predominant positive symptoms, following cannabis use. Some studies (n=6) observed an overall increased prevalence of all psychiatric disorders and symptoms owing to cannabis use, while others (n=14) elaborated on high rates of substance use in those with psychiatric disorders. The effect of cannabis use on cognitive function was the focus of some of the Indian studies (n=7). All these studies barring one had all male subjects, and a single study described the service delivery model for those with dual diagnosis disorders in India. Most of the research used cross-sectional observational design and focussed on treatment-seeking population. Interpretation & conclusions: A review of Indian literature on cannabis use and its association with psychiatric disorders indicates a high co-prevalence of psychotic disorders, especially in vulnerable individuals as well as high rates of co-occurrence of other psychiatric comorbidities. However, there is limited focus on exploring the aetiological association between cannabis use and psychiatric disorders; understanding the neurobiology of this association and management-related issues.