Switching suicide methods as a predictor of completed suicide in individuals with repeated self-harm: a community cohort study in northern Taiwan.

OBJECTIVE: Repetition of suicide attempts is common, but little is known about the relationship between switching methods of suicide attempt and the probability of completed suicide. This study aimed to determine the transition of methods chosen by individuals who repeat suicide attempts, and how the switched methods of suicide attempts influence the risk of suicide death.

METHOD: All consecutive individuals (n = 2052) with an episode of non-fatal suicide attempt registered in a surveillance database provided by the Department of Health of the Keelung City Government from 1 January 2006 to 31 December 2010 were enrolled and followed up until the end of 2011. The earliest attempt recorded in the database was defined as the index attempt. Data on the time of subsequent completed suicide and methods chosen for repeated self-harm during the follow-up period were analyzed by performing a Cox proportional hazards regression.

RESULTS: Of the total subjects, 374 (18.2%) had at least one other attempted suicide and 50 (2.4%) eventually died by suicide. Subjects who used highly lethal methods in the index self-harm tended to switch methods in the next suicide attempt (p<0.001). Switching to a more lethal method was a significant predictor of completed suicide (adjusted hazard ratio (aHR) 7.05, 95% confidence interval (CI) 3.52-14.14). In addition, subjects who used charcoal-burning in the index self-harm attempt had a higher risk of subsequent suicide death (aHR 3.47, 95% CI 1.57-7.68).

CONCLUSIONS: The findings in this study give us some insight into the patterns of methods in repeat suicide attempters. The intent behind switching methods of suicide attempt might be considered as an important item of clinical assessment of the seriousness of suicidal behavior.