Expected Results: The investigators expect that (1) group psychotherapy may involve comprehensive benefits for adolescents with illicit drug abusers, by improving the changes in adolescents' substance-craving symptoms and behavioral problems, and reducing stress of their parents; (2) this counseling program is effective for preventing the adolescents from relapse of substance abuse; (3) the findings in this study will not only demonstrate empirical evidence of treatment effectiveness for adolescents with illicit drug abuse, but will also provide useful clues for future implementation of policy making.