Long-term outcome of patients with dysthymia and panic disorder: a naturalistic 9-year follow-up study.

The highly prevalent psychiatric disorders dysthymia and panic disorder have often a chronic or recurrent course with superimposed major depression. The prominent comorbidity between these diagnoses constitutes a confounding factor in the study of long-term outcome. We performed a 9-year follow-up of 38 patients with "pure" diagnoses, i.e. without comorbid dysthymia and panic disorder, selected from two 2-year naturalistic treatment studies with psychotherapy and antidepressant medication. The aims of the present study were to investigate 1) the stability of change, and 2) the impact of comorbid personality disorders (PDs) on long-term outcome. Patients were reassessed with SCID-I and SCID-II interviews, SCL-90/BSI and a detailed, modified life-charting interview, investigating course and treatment over time. About 50% of patients showed substantial improvement, of whom about half were in remission. Comorbid PD was a negative prognostic factor independently of Axis I diagnosis. Although patients with panic disorder had a lower frequency of comorbid PD, later onset, shorter duration of illness and better outcome after the original studies, there was no difference in the long-term outcome. The less stable outcome among panic patients suggests that standard treatments are not resulting in enduring remission. In order to achieve remission, it is necessary to 1) address comorbid PDs, 2) perform careful assessments of all comorbid diagnoses, and 3) build routines for the follow-up and augmentation of treatments.