Suicide risk in bipolar disorder

The ISBD launched a Task Force on Suicide in 2012 with the principal aims of determining risk factors, characteristics and neurobiological aspects of suicide associated with bipolar disorder, and to develop recommendations for clinical research, education and advocacy strategies to better understand and potentially lower elevated suicide rates in this at-risk population.

The Task Force systematically examined the literature on prevalence and predictors of suicide in bipolar disorder and published the findings of their meta-analysis in the journal Bipolar Disorders.¹ Members of the Task Force presented their findings and discussed the potential implications on clinical practice.

Diagnosis matters

The Task Force reported a rate of 164 suicides per 100,000 person-years of follow-up in bipolar disorder patients, which is markedly higher than in the general population (10 per 100,000 person-years). Whereas men in the general population are three times more likely to commit suicide as women, the ratio is less than two to one in the bipolar population, underscoring that diagnosis has an influence on suicide risk.

Other notable differences include high rates of suicide attempts in patients with bipolar I (35%) and bipolar II disorder (29%), a higher lethality of suicide attempts in bipolar populations, and a younger age of suicide attempt. Interestingly, the presence of psychosocial stressors in the period prior to suicide is lower in the bipolar population than in the non-bipolar population, suggesting that factors specific to the illness itself are likely to be major drivers of higher suicide risk.

Mood states and suicide risk in bipolar disorder

Dr Erkki Isometsä, Professor of Psychiatry at the University of Helsinki in Finland, shared some important insights that help paint a clearer clinical picture of bipolar patients who are at elevated risk of suicide and also on periods of increased risk.

Polarity of illness during the first episode significantly predicts suicide attempt, with an almost 2-fold higher risk of suicide for those whose first bipolar episode was depression. Current or most recent episode of depression was associated with a 6-fold higher risk of suicide attempt. The highest risk was for mixed states of bipolar disorder, which were associated with a 65-fold higher compared to euthymic periods.

Other predictors of suicide attempt in bipolar patients included comorbid anxiety disorders, borderline personality disorders, and alcohol and substance use disorders. Specific periods of high risk of suicide are during acute episodes particularly those requiring hospitalization, and in the weeks immediately following discharge.

Clinical interventions for suicide prevention

One of the best strategies for reducing the risk of suicide in bipolar patients appears to be effective mood stabilization. Discontinuation of mood stabilizers has been associated with up to a 16-fold higher risk of suicidal behaviour.

Prof Lars Kessing from the Psychiatric Center Copenhagen in Denmark, reviewed the evidence on bipolar disorder treatments and suicide. Lithium has the strongest evidence to support a protective effect for suicidal behaviour, but there are some data from observational studies to support risk reduction with anticonvulsants and atypical antipsychotics as well.

Dr Kessing offered the following general clinical actions for the prevention of suicide in bipolar patients:

• Clarify risk and protective factors for suicide
• Address risk factors (e.g., feeling alone, living alone, economic ruin, etc.)
• Monitor suicidal ideations and potential attempts
• Identify and address current clinical risk situations such as discharge from psychiatric hospital or transfer to new physician
• Prescribe only a small number of tablets with potential lethal effects, especially lithium and tricyclic antidepressants

Epigenetics and suicide risk

During a fascinating lecture on the last day of ISBD 2015, Prof Gustavo Turecki from McGill University in Montreal, Canada, revisited the topic of suicide, this time from a molecular perspective. His group has looked at relationships between genes and the environment – or epigenetics – that may link early-life adversity to risk of suicide later in life.

In a nutshell, Prof Turecki’s group has published a provocative body of evidence to suggest that exposure to early life adversity can cause alterations in genes that are related to stress-response mechanisms and emotional trait regulation. These adaptations to what was perceived as a hostile environment early in life, could influence an individual’s later vulnerability to suicidal behaviour during periods of severe hopelessness such as depressive episodes.

Clearly, much more remains to be learned about how the genome is regulated by experience, and how clues from molecular biology to clinical epidemiology could be applied to develop more effective strategies to prevent suicide in people with bipolar disorders.

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