Comorbidity in the anxiety disorders: the use of a life-chart approach.

Findings of comorbidity across the anxiety and depressive disorders have implications for aetiology, diagnosis and treatment. This paper describes a method to assess one aspect of the relationship between comorbid disorders: the degree to which one illness experience is believed to be caused by the earlier experience of a different illness. The life-chart method involves the use of a semi-structured interview to document the lifetime course of disorders. The method was reliable in a sample of patients treated at a specialized treatment unit for anxiety disorders. Patients fell into three major groupings: those with one disorder only (19%); those who fulfilled criteria for two or more disorders, but with one disorder primary and other disorders secondary to it (55%); and those who fulfilled criteria for two or more independent disorders (26%).