Abuse or dependence on cannabis and other psychiatric disorders. Madrid study on dual pathology prevalence.

OBJECTIVES Cannabis use has been associated to a wide variety of mental disorders, the possible causal role of this use in the etiology of severe mental disorders as schizophrenia or bipolar disorder standing out. Moreover, the cannabinoid system is involved in emotional regulation, so cannabis use could disturb this process and provoke anxiety and mood disorders. The main objective of this study was to analyze the cannabis addict subgroup from Madrid study of prevalence of dual disorders in community mental health and substance misuse services. MATERIAL AND METHODS The sample consisted of 837 outpatients under treatment in the mental health network or drug network of the Community of Madrid (Spain). Of these, 353 subjects had a lifetime diagnosis of cannabis abuse or dependence and 357 subjects did not have cannabis substance use disorder. We used the Mini International Neuropsychiatric Interview (MINI) to evaluate axis I mental disorders, and Personality Disorder Questionnaire to evaluate personality disorders. RESULTS It was considered that 76.5% of the cannabis addicts had a current dual disorder. The most prevalent ones were mood and anxiety disorders. Of those addicted to cannabis, 51% had a personality disorder. Most of them had several substance use disorders. Cannabis abuse or dependence subjects had an earlier onset in consumption of other drugs such as alcohol, cocaine, and tobacco than addicts without cannabis abuse or dependence. The cannabis addicts also differed from the other addicts because of an association to antisocial personality disorder, bipolar disorder, psychosis and agoraphobia. The presence of these mental disorders was significantly associated to a lower age at initiation of cannabis use. CONCLUSIONS Dual pathology is very high in cannabis addicts under treatment. Said consumption of cannabis, probably within a polysubstance use pattern, is associated to severe mental disorders as psychosis and bipolar disorder. An earlier age of onset in cannabis use is associated to a greater risk of said mental disorders.