Abstract
BACKGROUND: Evidence-based psychological interventions for mental disorders are described in treatment protocols and manuals, which detail treatment components and conditions of application. Systematic evaluations of the accessibility of treatment protocols and manuals across multiple mental disorders are absent. OBJECTIVE: We assessed whether treatment protocols or manuals for psychological interventions for severe mental disorders are accessible and publicly available. STUDY SELECTION AND ANALYSIS: We surveyed randomised controlled trials (RCTs) from six large network meta-analyses of psychological interventions for severe mental disorders (psychotic, borderline personality, substance use, bipolar, anorexia and bulimia nervosa). Between January 2024 and February 2025, we retrieved protocols and manuals of psychological intervention arms using a multipronged approach (published protocol, trial registries, author contact, commercial availability). We report the proportion of trials and intervention arms for which protocols or manuals were (1) Accessible, that is, retrievable by any method, and (2) Publicly versus commercially available. FINDINGS: We included 260 RCTs, with 422 active intervention arms. We retrieved published protocols for 20 RCTs (8%, 95% CI 5% to 12%) and contacted 450 authors for the remaining 240. Authors shared protocols for 43/240 trials (18%, 95% CI 13% to 23%), refused to share for 73 (30%, 95% CI 25% to 37%) and did not respond for 101 (42%, 95% CI 36% to 49%). Protocols or manuals were retrievable for 364 psychological intervention arms (86%, 95% CI 83% to 89%), with 191 available commercially (45%, 95% CI 40% to 50%) and 106 (25%, 95% CI 21% to 30%) publicly. CONCLUSIONS AND CLINICAL IMPLICATIONS: Retrieving detailed descriptions of psychological interventions used in trials, crucial for identifying treatment components, was challenging, resource-intensive and required multiple methods. Reliance on public availability and author sharing enabled access to about 40% of protocols or manuals.