Individuals with bipolar disorder or psychosis are approximately 6 times more likely to die by suicide after a prior intentional self-harm incident, according to research published in the Journal of Clinical Psychiatry. The researchers found that the strongest risk factor for later suicide was hanging as the first self-harming event.
Bo Runeson, MD, PhD, and colleagues at the Karolinska Institute in Stockholm, Sweden, retrospectively tracked 34,219 Swedes aged 10 years and older who had been admitted to the hospital for deliberate self-harm between 2000 and 2005. Although ICD-10 codes did not allow for distinguishing between nonsuicidal self -harm and a suicide attempt, 75% of the individuals poisoned themselves. During follow-up of 3 to 9 years, 3.5% of the overall cohort died by suicide (n = 1182). Men who initially attempted suicide by hanging were 5.3 times more likely, and women 4.5 times more likely, to complete suicide during follow-up than those who previously attempted suicide by poisoning.
Among those without a psychiatric diagnosis, 2% of men and 0.9% of women completed suicide. After researchers accounted for age, birth in Sweden, and parent education, men with bipolar disorder were 6.3 times more likely to complete suicide than those with no diagnosis, but their increased suicide risk doubled to 12.9 times if they used any self-injury method besides poisoning. Similarly, women with bipolar disorder were 5.8 times more likely to complete suicide, which almost tripled to a 15.8-times greater suicide risk if they used a nonpoisoning self-harm method. One-fifth of those with bipolar disorder who harmed themselves with any method besides poisoning completed suicide during follow-up.
Women with nonorganic psychotic disorder were 4.6 times more likely to die by suicide, and suicide risk among men with psychosis was 5.1 times greater compared to individuals without a diagnosis. Among all individuals with psychosis who had not self-harmed with poison, 15.6% died by suicide during follow-up. A similar proportion (13.9%) of those with depression who self-harmed without poisoning died by suicide.
Following bipolar disorder and nonorganic psychotic disorder, depression predicted greater risk of suicide within the subsequent 9 years. The results paralleled previous research findings that a self-injury method other than poisoning confers a much higher risk of suicide than poisoning does. “The risk of suicide is particularly pronounced during the first years after previous nonfatal self-harm in individuals with coexisting severe mental disorders,” the authors wrote.