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. (C) 2011 Elsevier B.V. All rights reserved.