(PS5-41) Maximising Momentum: A Systematic Review and Meta-analysis of Intensive Treatments for Children and Adolescents with Anxiety or Obsessive-compulsive Disorders

Anxiety and obsessive-compulsive disorders (ADs/OCD) are prevalent among youth and have significant negative impacts, including functional impairments and reduced daily functioning and quality of life. Cognitive behavioural therapy (CBT) with exposure is recommended and established as an effective first-step treatment. However, persistent symptoms and non-response are not uncommon, placing demands on mental healthcare systems. Moreover, a portion of youth prematurely discontinue CBT, citing logistical barriers to treatment and lack of efficacy. Intensive psychological treatments may optimise treatment completion and exposure outcomes by delivering more or longer sessions over a shorter time span, with fewer session gaps. However, an understanding of their effectiveness and characteristics, as well as their implementation feasibility and acceptability among therapists, youth, and parents, is lacking. A systematic search across five databases yielded four controlled and 35 uncontrolled studies (N = 2644) involving youth with primary ADs or OCD, many of whom received prior treatments. Intensive treatments were implemented across various contexts, including outpatient, inpatient, residential, and home- or camp-based environments, each varying in intensity. Considering both quantitative and qualitative family perspectives from the included studies revealed that intensive treatments were deemed acceptable and feasible by youth and parents, with low dropout rates (4.3%). Between-group analyses revealed no significant post-treatment differences in symptom severity (d = 0.50, 95% CI = [-0.32; 1.33]) or remission (RR = 2.20, 95% CI = [0.20; 23.61]) with control conditions. Uncontrolled within-group analyses of intensive treatments showed large post-treatment improvements in symptom severity (d = 1.64, 95% CI = [1.22; 2.05]) and remission (49.0%), as well as for broader health outcomes including impairment (d = 1.16, 95% CI = [0.74; 1.57]), overall functioning (d = 1.48, 95% CI = [0.65; 2.31]), and quality of life (d = 0.62, 95% CI = [0.15; 1.08]), all with larger effects at follow-ups. Intensive treatments may maximise momentum for enhancing progress and offer options for treating youth with ADs/OCD. These treatments show promise in terms of acceptability and feasibility, potentially yielding low dropout rates and outcomes comparable to standard CBT. This could facilitate higher completion rates of evidence-based treatments and expedite recovery, thereby reducing overall suffering duration. However, our findings underscore the limited research on intensive treatments, marked by a scarcity of randomised controlled studies. Broader outcomes, including impairment, quality of life, overall functioning, and adverse events, have been sparingly investigated. This systematic review and meta-analysis provides a comprehensive overview of intensive treatments, their theoretical and clinical considerations, and empirical findings. Future high-quality research should compare the effectiveness of standard and intensive treatments with comparable client groups, address implementation challenges, and discern the optimal population for their use.