Vicious cycles – decoding the patterns of suicide risk

This challenge is especially great in psychiatry, an area with a high risk of suicide. Of those people who die by suicide, 90% or more are suffering from mental health issues at the time of their deaths and, for psychiatrists treating bipolar disorder, up to half of their patients are likely to attempt suicide at some point^1,2.

The cruelest months

Understanding the influences behind peaks and troughs in suicide rates can help psychiatrists to be particularly alert to the warning signs at times of highest risk. One influence thought to have particular importance is that of season.

It is a commonly-held belief that, at times like Christmas, depressive symptoms such as stress and loneliness are likely to feel more pronounced³. Likewise, studies have observed that bipolar I sufferers experience a significant peak in severe depressive symptoms during the winter months, when days are shorter.⁴

Based on these pieces of accepted wisdom, one might expect the season with the highest rates of suicide, and therefore the need for greatest awareness, to be winter. However, the evidence overwhelmingly points to the opposite, a peak in suicides during spring and summer, especially pronounced in those suffering mood disorders such as bipolar I disorder.^5-7

Light and darkness

The reasons for this peak are still unclear. Possible explanations range from the effects of temperature or atmospheric pressure to the Th2-mediated worsening of depressive symptoms triggered by aeroallergens such as pollen.⁷

One compelling suggestion has been advanced by Professor Zoltan Rihmer. Professor Rihmer emphasises the important influence of sunlight in seasonality, promoting a hyperthymic temperament usually protective against suicide.

The problem, he suggests, arises when both manic and depressive symptoms are present concurrently. Here, the sudden boost in energy levels brought by the increased sunlight takes effect before improvements in mood, leading to a period where patients are both depressed and impulsive - a dangerous combination. This theory accords with the increased likelihood of suicide attempts seen in bipolar I patients suffering confirmed mania with depressive symptoms, as opposed to those suffering borderline/pure mania⁸.

So how can we use this information to lower the incidence of suicide attempts? One approach could be to focus on increasing early identification of mania with depressive features. There are a number of ways to achieve this, from indicator symptoms - such as anxiety, agitation and irritability - to diagnostic tools, such as the MINI. By improving identification of patients with mania with depressive features we can increase HCP vigilance not only during the period of highest suicide risk but also amongst the group most likely to be vulnerable during this time.

Keeping a steady watch

Whatever the causes, the spring/summer peak in suicides requires careful observation, especially as research suggests that as a patient’s suicide risk increases at this time, the likelihood of them recognising their own mental health issues and seeking help appears to fall.⁹

However, with preparation and appropriate use of diagnostic tools, physicians can begin to detect at-risk patients earlier, helping reduce suicide rates in bipolar I disorder by ever-greater numbers.