Compulsive buying in bipolar disorder: is it a comorbidity or a complication?

The objective of this study was to investigate the frequency of compulsive buying in bipolar disorder (BD), to compare it with healthy controls, and to search if there is a difference between bipolar cases with and without compulsive buying in terms of sociodemographic qualities, temperament, clinical characteristics and comorbid diagnoses.

One-hundred outpatient cases diagnosed as BD according to DSM-IV were evaluated consecutively. Following the diagnosis interview (SCID-I and II) the subjects completed the mood disorders registry form, Compulsive Buying Scale and TEMPS-A.

Compulsive buying scores were higher in bipolar patients than healthy controls (p<0.001). Cases with compulsive buying revealed higher cyclothymic and irritable temperament scores than other bipolar patients (p=0.029 vs 0.045). Premenstrual syndrome and postpartum onset were more frequent, while psychotic symptoms were less in compulsive buyer bipolar patients (p=0.002, 0.009 vs 0.034). Severity of episode was lower (p=0.01), number of episodes was higher (p=0.009). Acute onset and remission before and after maintenance treatment were more frequent in patients with compulsive buying (p=0.011 and p=0.011). Full remission between episodes was 100%. Cases with axis-1 and axis-2 comorbidities demonstrated higher compulsive buying scores (p=0.025 and 0.005).

Treatment regimen differences between patients are a limitation of the study.

This is the first study to relate compulsive buying with the clinical characteristics of BD. Our results reveal that compulsive buying in BD occurs together with mood episodes which are not very severe, but frequent and with abrupt onset.