Since the economic crisis, suicide mortality has risen sharply among Korean adolescents aged 15 to 19 years (i.e., an increase of 40.7% from 5.4 per 100,000 in 2001 to 7.6 per 100,000 in 2005) and is the second leading cause of death among this population.1 Suicide and suicidal behaviors (suicidal ideation and suicide attempts) among adolescents have become major public health concerns in Korea, and it is thus important to determine the risk factors associated with such behaviors. In recent years, early age of onset of alcohol drinking, cigarette smoking, and sexual intercourse (i.e., during childhood) have been identified as important predictors, beyond the multiple risk factors in adolescence previously noted in the literature,2-5 of later suicidal behaviors (during adolescence).6-13 With the exception of alcohol drinking, which is usually measured by self-reported age at first alcoholic drink excluding those imbibed for religious reasons,10,12,13 age at initiation of cigarette smoking and sexual intercourse has been conservatively measured in most previous studies (i.e., "regular/daily smoking or smoking a whole cigarette" and "unwanted/forced sexual intercourse").7,8,14 By using such methodologies, previous studies may have
