Health-related quality of life in euthymic bipolar disorder patients: Differences between bipolar I and II subtypes

Objective: The aim of the present study was to compare health-related quality of life (HRQoL) measures in euthymic patients with bipolar I and II disorder. We included as comparison samples a group of subjects with recurrent major depression (RMD) and a group of non-psychiatrically ill individuals. Method: HRQoL was assessed using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) in 253 subjects recruited in 5 Italian centers: 90 patients with bipolar I disorder, 52 patients with bipolar II disorder, 61 subjects with RMD and 50 healthy comparison individuals. All subjects were evaluated with the Structured Clinical Interview for DSM-IV; psychiatric patients had to be in a euthymic state for at least 2 months prior to the inclusion in the study, as confirmed by a Hamilton Rating Scale for Depression total score <8 and a Young Mania Rating Scale total score <6. Data were drawn from a study that was performed from May 2003 to December 2004. Results: When we compared the bipolar and RMD groups with the control group of non-psychiatrically ill individuals and controlled for differences in mean actual age, both bipolar subgroups and subjects with RMD had lower SF-36 mean scores on several subscales; differences in mean SF-36 scores were also detected between bipolar subtypes: bipolar II patients showed HRQoL that was poorer than that of bipolar I patients, even after controlling for age, age at onset, and length of illness, and equal to that of RMD subjects. Conclusion: Our study provides evidence that bipolar type II is associated with poorer HRQoL compared to type I even during sustained periods of euthymia and excluding residual symptoms. Interventions targeting rehabilitation and/or functional enhancement may be helpful to improve HRQoL, especially among patients with bipolar II disorder.