Methods of suicide predict the risks and method-switching of subsequent suicide attempts: a community cohort study in Taiwan

OBJECTIVE Suicide is a major public health concern. This study aimed to determine the predictors of repeated suicide attempts, focusing on whether lethality level of the suicidal method predicts the risk of subsequent suicide attempts. METHODS All consecutive individuals (N=2,070) with an episode of nonfatal self-harm registered in a surveillance database provided by the Department of Health of Keelung City Government in Taiwan from January 1, 2006 to December 31, 2010 were enrolled and followed up until the end of 2011. The earliest attempt recorded in the database was defined as the index attempt. Subjects were classified according to suicide method into low-lethal and high-lethal groups. Data on time of and methods chosen for subsequent suicide attempts during the follow-up period were analyzed. RESULTS Of the total people screened for the study, 18.1% made a repeated suicide attempt. Subjects in the high-lethal group were more likely to be male; aged 35-64 years; and single, divorced, or widowed. Compared to other time intervals, most subsequent suicide attempts occurred within 6 months from the index attempt. The independent predictors for repeated suicide attempts were the use of low-lethal methods in the index attempt and being 35-49 years old. Using high-lethal methods and being older than 50 years were associated with changing suicide method for the second attempt. CONCLUSION Lethality level of former suicidal method could predict repeated suicide attempts and changing of suicide methods. Further clarification is needed on whether a higher risk of repeat attempts is associated with higher rates of suicide mortality.