Comorbidity of delusional disorder with bipolar disorder: report of four cases.

Background: Although it is accepted that patients with delusional disorder can show co-existing depression, comorbidity with bipolar disorder is not a recognised feature.
Method: Case report of patients who showed both delusional disorder and mania or hypomania. The patients were examined using lifetime structured psychiatric interview where possible.
Results: Four patients are described who met criteria for delusional disorder, with durations ranging from 2 to 15 years, and also experienced one or more episodes of mania or hypomania.
Limitations: Case reports cannot quantify a clinical association.
Conclusions: These cases suggest that there is an association between delusional disorder and affective disorder which goes beyond the occurrence of depressive symptoms in the disorder.
(Copyright © 2011 Elsevier B.V. All rights reserved.)