Despite these limitations, this study has several important strengths. The major strength of the present study was its use of a nationally representative sample and its high response rate, which may enable to generalize our findings to the actual population of Korean adolescents. Moreover, this study was the first to analyze measures of simultaneous alcohol use, cigarette smoking, and sexual intercourse, yielding indications that early initiations of problem behaviors are important predictors of later suicidal ideation and suicide attempts among Korean adolescent males and females. In particular, preteens were more susceptible than teens to the synergistic effects of combinations of these problem behaviors. Given recent trends and unlimited access to alcohol, tobacco, and internet and/or cyberspace sex in modern Korean society, it is not surprising that the age at which problem behaviors manifest continues to decrease. Consequently, the rates of adolescent suicide-related behaviors may continue to increase in the future. In particular, suicidal ideation and suicide attempts in adolescence have been identified as important predictors of suicidal ideation and suicide attempts in adulthood.21 Therefore, integrated preventive intervention programs targeting the
