A single-session consultation to enhance mental health treatment engagement in patients with comorbid physical and mental problems: study protocol for a pilot randomized controlled trial

BACKGROUND: Individuals with chronic physical diseases are at elevated risk of developing mental health disorders. Comorbid chronic physical disease and mental health problems (CPDMHP) are associated with substantial societal and healthcare costs. Although enhancing mental healthcare for this population can improve outcomes, efforts to increase service engagement have had limited success. This study evaluates a Solution-Focused Single-Session Consultation (SF-SSC) as a brief, innovative approach to addressing structural and attitudinal barriers to treatment engagement. METHODS/DESIGN: The study will comprise two phases: Phase 1 will consist of a prospective cross-sectional study of patients in an outpatient community health setting in Singapore. Participants will complete measures of their sociodemographic characteristics, physical and mental health status (e.g., current and past physical and mental health conditions, and service utilization), and psychosocial indicators (e.g., life satisfaction, hope, readiness for change). Phase 2 will involve a two-arm randomized controlled pilot trial that evaluates the feasibility, acceptability, and preliminary effectiveness of the SF-SSC compared with a single session of supportive therapy (SPT). Up to 60 participants from Phase 1 with elevated depression or anxiety symptoms (PHQ-9 or GAD-7 scores ≥ 5) will be randomized to receive the SF-SSC or SPT intervention. Phase 1 analyses will examine the associations among sociodemographic characteristics, physical and mental health factors, and psychological and psychosocial outcomes. The primary outcomes of Phase 2 will be the feasibility and acceptability of the SF-SSC, assessed by the completion of SF-SSC action plans (with a predefined ≥ 70% threshold) and participant-reported usefulness and satisfaction. The primary clinical/process outcome will be treatment engagement, operationalized as the willingness to be referred and attendance at a subsequent appointment. Exploratory secondary outcomes will include psychosocial constructs that are hypothesized to underlie intervention effects, such as hope, perceived agency, readiness to change, and life satisfaction. Given the pilot nature of the trial, clinical and psychosocial findings will be interpreted as preliminary indicators of potential benefit rather than confirmatory evidence of efficacy. DISCUSSION: Findings from this study will inform future trials examining the large-scale and long-term impact of the intervention. The study will also inform the design of scalable approaches that can be integrated into existing mental healthcare systems to improve mental health service uptake and engagement among individuals with CPDMHP. TRIAL REGISTRATION: The trial was retrospectively registered at Clinicaltrials.gov [NCT07116655] on August 11, 2025.