Purpose of review: To consider comorbidity across multiple classes of disorders in data derived from recent large-scale community surveys.
Recent findings: There has been substantial recent progress in our understanding of patterns and implications of comorbidity of mental disorders. There is now converging evidence on the magnitude and specific patterns of comorbidity in international studies worldwide. There is increasing recognition of comorbidity of mental and physical disorders. Comorbidity of mental disorders and substance abuse has now been recognized universally, and the results of treatment and prevention studies incorporating comorbidity are now beginning to emerge.
Summary: Comorbidity has been shown to be an index of more severe course and outcome of mental disorders. Systematic inclusion of comorbidity into clinical evaluation and treatment will enhance the effectiveness of intervention with these conditions. Prevention of the development of secondary conditions as a consequence of primary disorders should reduce the impact of these conditions on both the individual and society.