Brief report: A qualitative evidence synthesis of the psychological processes of school-based expressive writing interventions with adolescents.

Introduction: Expressive writing interventions consist of brief writing sessions on thoughts and emotions and are known to yield positive benefits on adolescents' mental health. However, the psychological mechanisms explaining these effects are not clear.

Method: This review explored the psychological processes underlying school-based expressive writing interventions with adolescents. A thematic synthesis of qualitative research consisted of identifying, appraising and summarizing the qualitative evidence of eligible studies.

Results: Only six of the 510 identified studies met the inclusion criteria of this review. Results provide some validation for cognitive-processing, emotion-regulation, and disinhibition as psychological mechanisms underlying school-based expressive writing with adolescents.

Conclusions: However, these conclusions are still preliminary because of the paucity of the qualitative evidence found, both in quantity and quality. We recommend that more rigorous and in-depth qualitative research be undertaken to: 1) explore adolescents' subjective experience about the expressive writing intervention, using in-depth individual interviews; 2) thoroughly assess the content of students' texts written during the intervention; and 3) document the process of expressive writing interventions through observational methods. The results of such investigations would support the development and implementation of school-based expressive writing-type of interventions adapted to adolescents.