Prospective study of risk factors for attempted suicide among patients with bipolar disorder

There are few prospective studies on risk factors for attempted suicide among representative samples of psychiatric patients with bipolar I and II disorders. We conducted a prospective study to investigate risk for suicide attempts among a secondary-level sample of psychiatric in- and outpatients with bipolar disorder (BD).

In the Jorvi Bipolar Study (JoBS), 1,630 psychiatric in- and outpatients from three Finnish cities were screened for BDs with the Mood Disorder Questionnaire (MDQ). Using the Structured Clinical Interview for DSM-IV Disorders (SCID)-I and -II, 191 patients were diagnosed with BDs (90 bipolar I and 101 bipolar II). Information on suicide attempts during the follow-up was obtained for 176 patients (92%) at the 6-month follow-up and for 160 patients (84%) at the 18-month follow-up.

During the 18-month follow-up 20% of patients (35/176) attempted suicide. In a Cox regression model, baseline previous suicide attempts (OR 3.8, 95% CI 1.7-8.8; p = 0.001), hopelessness (OR 1.2, 95% CI 1.1-1.3; p < 0.001), depressive phase at index episode (OR 2.4, 95% CI 1.1-5.3; p = 0.03) and younger age at intake (OR 0.94, 95% CI 0.91-0.97; p < 0.001) were independent risk factors for suicide attempts during follow-up, whereas factors such as bipolar I or II, or comorbidity did not reach statistical significance.

During a medium-term follow-up, as many as one-fifth of random psychiatric patients with BD attempted suicide, which highlights the public health importance of suicidal behavior in BD. Previous suicide attempts, hopelessness and depressive phase were the key indicators of risk.