Key risk features predictive for suicide in bipolar disorder identified

By Ingrid Grasmo

Study findings suggest that patients with bipolar disorder (BD) who present with mixed-states, melancholic depressive features, or have multiple antidepressant treatment episodes are at increased risk for suicide.

"This study… underscores the growing impression that bipolar II disorder patients have high levels of morbidity, disability, and mortality," say Ross Baldessarini (McLean Hospital, Belmont, Massachusetts, USA) and colleagues.

For the study, the researchers compared demographic and clinical factors for long-term association with non-lethal suicidal acts or ideation in 204 BD-I and 86 BD-II patients with an average 18.7-year disease duration and who were followed up for an average of 9.3 years.

Suicidal ideation and acts were present in 41.5% and 19.7% of all patients, respectively, with the lifetime rate of suicidal ideation significantly higher among BD-II versus BD-I patients (53.5% vs 36.7%). No significant difference was seen between BD subtypes for rates of suicidal acts, although the number of suicidal acts per year was significantly greater among women than men (3.0 vs 0.9 per 100 person-years).

Factors associated with risk for suicidal acts included more mixed manic-depressive episodes per year (odds ratio [OR]=26.1), female gender (OR=11.5), predominant depression (OR=5.46), and latency to bipolar diagnosis (OR=1.06). Furthermore, factors associated with risk for suicidal ideation included more mixed episodes per year (OR=20.1), predominant depression (OR=4.74), and melancholic features (OR=2.82).

A diagnosis of BD-I was associated with significantly more psychiatric hospitalizations per year (OR=159.0) and more unemployment than BD-II (OR=3.42), while the latter was significantly associated with predominantly depressive polarity of lifetime recurrences (OR=14.4, ≥2:1 ratio) relative to BD-I.

Further analysis revealed that factors significantly associated with overall suicidal risk independent of BD subtype included a greater number of mixed states per year (OR=15.8), melancholic features (OR=3.23), and more antidepressant trials (OR=1.29).

"The present observations support the impression that suicidal risks are not lower among bipolar II than in bipolar I patients and that BD-II is not a milder or attenuated variant of BD-I," say the researchers in the Journal of Clinical Psychiatry.

They call for more studies to assess suicidal risk and its prediction and prevention in BD patients, especially those with BD-II, as well as development of more effective and safe means of treating depressive and mixed to states in order to limit suicidal risk.

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