Predictors of relapse in high lethality suicide attempters: a six-month prospective study

Background: This study is aimed to investigate the association between clinical, metabolic, inflammatory and environmental (photoperiod defined as daily sunlight exposure) parameters and suicide re-attempts after the index suicide attempt. Possible predictors of suicide re-attempts were also explored. Methods: Overall, 432 subjects with suicide attempts, of which 79 relapsed within the following six months were included in this prospective study. We adopted the Joiner's definition of suicide lethality, as the acquired ability to enact lethal self-injury. The Cox regression was used to test the association between the mentioned variables and Kaplan-Meier plots showed the trend of suicide re-attempts. Results: Among participants, 30.8% committed a high-lethality suicide attempt. Cox regression confirmed the association between lifetime suicide attempts and number of suicide attempts in the study time-frame and suicide-reattempts. The longer photoperiod (Spring/Summer) was associated with suicide re-attempts, particularly patients with admission in June/July for the index event. Total cholesterol (TC), low-density lipo-protein cholesterol and c-reactive protein serum levels were significantly associated with suicide re-attempts but Cox regression confirmed only the association between lower TC serum levels and suicide re-attempt. Limitations: Patients' seasonal environment, psychological factors, presence of acute life-events fostering the suicidal crisis and detailed medical history have been not investigated. Findings were derived from a single psychiatric unit. Conclusions: Lifetime suicide attempts, higher number of previous suicide attempts, lower total cholesterol levels, and suicide attempt during longer photoperiod were significant predictors of suicide re-attempts. Further studies are needed in order to better characterize single- vs. multiple suicide attempter's profiles.