Background: Mental ill-health among adolescents is one of the most increasing public health problems in Sweden. Particularly girls suffer from mental and psychosomatic symptoms. The National Board of Health and Welfare recommend the DISA method as a preventive measure. Problem: Investigations has been done of the DISA method, but further investigations needs to be done. Aim: The aim of the study was partly to investigate how participants in DISA groups in two counties understand the method and its eventual effect and partly how their mood change, to contribute with knowledge to the development of the DISA method. Methods: A questionnaire and the self-report CES-D scale were collected from a population of 154 participants. A statistical analysis with Paired-Samples T Test carried out to examine if the difference between the sum of points of the group from the first and the last completing of the self-report CES-D scale was statistical guaranteed. Results: The participants were most satisfied with the group size and the rules. They were less satisfied with the mood diary and the homework. They wanted to talk less about negative thoughts and wanted it to be voluntary to participate in a DISA group. The participants got better insight and understanding of mental health and mental ill health. It is statistical significant that the average sum of points of the participants got lower the last time they completed the self-report CES-D scale compared to the first time. Conclusion: There are many indicators who points out that DISA is a well functioning depression preventive method.