Suicide risk is associated with low levels of platelet serotonin in bipolar I disorder

Suicide is globally recognized as one of the leading causes of death and a major issue for the public health sector. Considering the importance of suicide, this study attempts to correlate decreased platelet serotonin levels with increased suicide risk in bipolar I disorder (BPD I), while also evaluating other risk factors. All patients admitted to the "Prof. Dr. Alexandru Obregia" Clinical Hospital of Psychiatry in Bucharest, Romania, between the June 1st, 2015 and February 16th, 2016 were asked to participate in this study. Those between 18 and 65 years of age, who agreed to participate and whose diagnoses of BPD I were confirmed using the Mini-International Neuropsychiatric Interview were included in the study, leading to a number of 75 patients. Suicide risk was assessed using the SAD PERSONS Scale to quantify current suicide risk factors. Platelet serotonin levels were determined using the IVD ELISA system (LDN GmbH, Germany) on platelet rich plasma per manufacturer protocol. The scores received from applying the SAD PERSONS Scale were shown to be inversely proportional to platelet serotonin levels, and those patients with bipolar disorder classified as showing medium-high suicide risk, had significantly lower platelet serotonin concentrations. In further studies, with a larger sample size, and other improvements further discussed in this article, it may be possible to demonstrate the need to test platelet serotonin levels as part of the biological model of suicide in bipolar disorder.