Effects of solution-focused brief group therapy on symptoms and interpersonal relationships in adolescents with depressive disorder: a randomized, single-blind, TAU-controlled study

Adolescent depressive disorder involves emotional distress, impaired social functioning, and poor interpersonal relationships, with a bidirectional exacerbating effect between the latter two. Solution-Focused Brief Group Therapy (SFGT) improves individuals’ psychological states through group interaction; however, few studies have examined SFGT interventions for adolescents with depressive disorder seeking hospital-based treatment. This study was designed to clarify the efficacy of SFGT in treating depressive symptoms, anxiety symptoms, and interpersonal relationships in this population, thereby addressing gaps in clinical intervention research. A randomized, single-blind design was employed. The sample size was determined a priori to ensure adequate statistical power. Seventy-four adolescents (aged 12–18) with depressive disorder were recruited from the outpatient department of a psychiatric hospital in Zhengzhou, Henan Province, China and randomly allocated to either the experimental group ( n = 38) or the control group ( n = 36). Sixty-six participants (89.2%) completed all three assessments and constituted the analysis sample (experimental group, n = 32; control group, n = 34). The control group received treatment as usual (TAU), whereas the experimental group received an 8-week SFGT intervention (one 120-minute session per week) as an adjunct to TAU. Clinical outcomes were assessed at baseline, post-intervention (8 weeks), and at a 4-week follow-up (12 weeks) using the Hamilton Anxiety Rating Scale (HAMA), the 24-item Hamilton Depression Rating Scale (HAMD-24), the Interpersonal Comprehensive Diagnostic Scale (ICDS), and the Clinical Global Impression (CGI) scale. At both 8 and 12 weeks, both groups showed significant within-group improvements in scores relative to baseline. The experimental group demonstrated significantly lower ICDS total and subscale scores than the control group at both post-intervention assessments (all P < 0.05), with significant time, group, and time × group interaction effects for total ICDS scores (all P < 0.001; interaction partial η ² = 0.501). For HAMD-24, a group main effect was observed in favor of the experimental group ( P = 0.037, partial η ² = 0.066), whereas the time × group interaction was not significant ( P = 0.627), indicating comparable rates of improvement in clinician-rated depressive symptoms in the two groups. For HAMA, neither the group main effect ( P = 0.268) nor the interaction ( P = 0.115) was significant. CGI assessments confirmed that global improvement (GI) in the experimental group was significantly superior to the control group (both P < 0.001). As an adjunct to TAU, SFGT reduced self-reported interpersonal distress in adolescents with depressive disorder and was associated with greater clinician-rated global improvement. Both groups showed comparable improvements in clinician-rated anxiety and depressive symptoms, and the advantage of SFGT over TAU was limited to the 4-week follow-up period. These findings are most directly applicable to clinically stable outpatients with severe depressive disorder and no history of suicide attempts. Trial registration: This trial was not prospectively registered. Retrospective registration with the Chinese Clinical Trial Registry was initiated after enrolment was complete (registration number: ChiCTR2600134593).