Purpose: This study is designed to help probationers reduce unintentional and impulsive behaviors and improve abilities to cope with these behaviors. For this purpose, a solution-focused group therapy program based on the ecosystem perspective was implemented. The purpose of this study is whether the solution-focused group therapy program intervention had positive effects on reducing probationers' aggressiveness and on increasing their desires for readjustment.

Methods: The participants were 80 probationers who were under the probation in the S probation center in Seoul, Korea. They were aged from fourteen to nineteen and were randomly assigned to the experimental group (40 persons) and to the control group (40 persons). The solution-focused group therapy program was applied only to the experimental group and 6 sessions of group counseling were designed, with each session lasting 2 hours. The analysis of the group intervention was designed to compare two groups before and after the intervention. Further, the participants' self-recorded reports on their changes and session progress records were used to evaluate the accomplishment of the goals set forth in the beginning of the study in a qualitative manner.

Results: First, aggressiveness of the experimental group was statistically significantly reduced as compared to the control group. Second, social readjustment ability of the experimental group was meaningfully improved as compared to the control group. Third, participants' behaviors in the experimental group were changed after the second or third session. There was significant improvement after the fourth session, and the improvement continued until the sixth session. Fourth, most of the participants in the experimental group accomplished their goals that they had set in the beginning of the study. Fifth, the program helped probationers overcome impulsive behaviors, and the participants felt satisfied with their positive alternation.

Implication: In summary, the solution focused group therapy program was successful in drawing inner competence out of the probationers and played a role in reducing aggressiveness and increasing social readjustment. This study suggests that the solution focused group therapy program can be employed in a variety of social work settings and, further, this program can be concentrated on evaluating the effectiveness of this approach with other cultural sub-groups.