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

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.

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.

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.

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.