Do biomarkers of suicidal behaviour exist?

Suicide is a serious and global problem. It is the second highest cause of death within young adults and in the USA, costing the healthcare services an estimated $US11 million annually.

But how realistic are biological prediction tools for a complex behavioural like suicide?

Professor Hilario Biasco-Fontecilla stepped up to the podium to address this question in the first talk of the session talk, ‘Biomarkers of Suicide Behaviour’.

Ill communication

Prof Biasco-Fontecilla began by expressing a problem that many healthcare professionals face when establishing if a patient is at risk of suicide – lack of communication.

Three out of four suicide attempters interviewed in one study did not display or disclose thoughts of suicidal ideation in prior consultations. If a sensitive biological biomarker for suicide could be identified, patients at risk could be isolated regardless of how effectively they communicate indicators of suicidal behaviour.

All for one, and one for all?

Prof Biasco-Fontecilla summarised data supporting the efficacy of a range of known and potential biomarkers for suicidal prediction, pulling out some of the more hopeful candidates, including dexamethasone suppression test (DST), brain-derived neurotrophic factor (BDNF) and a number of polyamines. But he emphasised the difficulties of finding a single ‘holy grail’ detection molecule, which would need sensitivity of over 90% to be useful.

Inflamed and dangerous

Professor Phillipe Courtet was the next to shed light on the subject with his talk focussing on ‘The Role of Neuroinflammation and Immunity on Suicide’, stating that “inflammation is totally fashionable in medical fields these days”, but that he and his team had established real, tangible links between neuroinflammatory pathophysiological mechanisms and suicidal behaviour.

The involvement of neurobiological and inflammatory processes in serious illness like bipolar disorder has been the focus of many of the talks attended by this correspondent at WPA, suggesting the huge potential of this growing area of research.

Pandora’s box

Like the speakers before him, Prof Courtet highlighted the complexity of suicide as a behaviour, exposing the minefield of different biochemical interactions that could manifest in this most destructive of traits.

He listed cytokines such as IL-2, known to have a role as neurotransmitters in the brain as ones to watch, along with the flame-bearer of inflammation, C-reactive protein. The Prof highlighted that some inflammatory molecules have shown more promise as markers of suicide than others, but that more comprehensive studies were needed to help unravel the great mystery of inflammation, suicide and how it all comes together in the brain.

Reflections on death

Although initial research is promising, there is clearly more exploration to be done in this complex and important field, highlighting again just how challenging illnesses like bipolar disorder and their manifestations can be for healthcare professionals to treat.

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