Long-term effects of psychotherapy in children and adolescents: protocol for database development and a systematic...

Approximately one in every six children and adolescents is affected by mental disorders, which impose significant costs on patients, their families and societies. Psychotherapy is the first-line treatment for many of these disorders, and systematic reviews of post-intervention effects show small to moderate favourable outcomes compared with control groups. However, the long-term effects of psychotherapy remain less well understood.

The LaKiJu META project aims to address this gap by developing an open-access database, which will subsequently be used for data synthesis. This database will be established through literature searches in nine databases for (cluster) randomised controlled trials (RCTs) investigating the long-term effects (≥6 months) of any type of psychotherapy in school-aged children and adolescents (ages 6;00 to 17;11 years) with mental disorders. Outcomes will be prioritised based on their relevance to patients, caregivers and clinicians and will encompass a broad range of measures, including symptom changes, response rates and reliable changes. Syntheses will use multilevel meta-analyses to compare intervention and control groups at follow-up assessments, across both transdiagnostic and disorder-specific symptom outcomes. In secondary analyses, we will examine changes within intervention groups over time. Moderator analyses will focus on the effects of study-, intervention- and patient-level characteristics.

Ethical approval for public involvement was obtained from the ethics committee of the Faculty of Psychology of the Ruhr University Bochum. For dissemination, we will employ tailored strategies to reach researchers, clinicians, patients and their caregivers, with all groups involved in the development of dissemination plans.

CRD420251003208 (preregistered on 10 March 2025).