Anxiety and substance use: layers of complexity.

Anxiety and substance use disorders occur together much more commonly than would be expected by chance, as shown in both general population and clinical samples. The clinical importance of this is that the outcome for each type of disorder is worse across clinical and psychosocial domains than for the disorders that occur noncomorbidly. This review explores explanatory models for comorbidity, outlines assessment protocols that can be employed in both screening and in treatment planning, as well as assessing the efficacy of applied interventions. Treatment options are presented, and the evidence base for various psychosocial and biological treatments are reviewed.