Did national implementation of interpersonal counseling improve adolescent depression treatment pathways in primary care? Protocol for a longitudinal cohort study.

BACKGROUND: Implementation of evidence-based interventions is one of the proposed responses to increased demand for treatment of adolescent depression. While the efficacy of interpersonal psychotherapy to treat depression of adolescents (IPT-A) is well established, the shorter adolescent interpersonal counseling (IPC-A) was implemented in primary care in Finland due to better feasibility. We present a protocol for a prospective evaluation of whether implementation of IPC-A has improved the naturalistic treatment flow and outcome of adolescents with sustained depression. We will evaluate the comparative effectiveness and cost-effectiveness of IPC-A and other treatment options, as compared to no treatment of sustained depression.

METHODS: We will collect a prospective cohort of grade 7 to 9 adolescents (13 to 17-year-olds) in selected Finnish schools using convenience sampling (n = 9000). We will describe the comparative effectiveness of naturalistic treatment, with an aim to compare three groups as defined at 6 months (with IPC-A, n = 100; with other psychosocial treatment, n = 200; or no treatment, n = 100). The primary outcome measure will be the proportion of adolescents who received specialized psychiatric services by 2 years after baseline in each group. Secondary outcome measures will include longitudinal changes in PHQ-9-A scores by 12 months, positive mental health, social inclusion, and quality of life. Cost-effectiveness will be evaluated using survey data at 12 months, and an economic evaluation using register data and information on service use 12 months before and up to 10 years after baseline. A universal evaluation of all adolescents, independent of mood, will provide prospective description of adolescents a) with sustained depression over the follow-up period (Patient Health Questionnaire 9 items, adolescent version, PHQ-9-A ≥ 10 in two measurements over 6 months), b) with a self-reported need and motivation for support, c) with therapeutic intervention, and d) benefits and harms of treatment. We will describe the treatment received and predictors of treatment and outcome based on reports from adolescents, caretakers, and therapists, as well as electronic patient records. Impact of training in IPC-A on competence and access to treatment will be evaluated.

DISCUSSION: The study will describe need for, pathways to, and content of mental health services for depressed adolescents over the two years following national implementation of IPC-A. The results can improve equal access to care, and inform decision makers about the best practices for treatment of depression, including utility of the implementation of IPC-A.

TRIAL REGISTRATION: ClinicalTrials.com NCT06390462 registered 2024-03-19.