Supplementary Material for: Reducing distress from auditory verbal hallucinations: A multicentre, parallel, single-blind, randomised controlled feasibility trial of Relating Therapy

Introduction There is significant demand for interventions that reduce distress related to auditory verbal hallucinations (AVH). AVH-distress is associated with the way voice hearers relate with AVH. We aimed to establish the feasibility of a randomised controlled trial to demonstrate that adding ‘Relating Therapy” (RT) to Treatment as Usual (TAU) is superior to TAU in reducing AVH distress. Methods We conducted a multicentre, parallel, single-blind, randomised controlled feasibility trial in five mental health centres in Germany. Participants were ≥16 years of age, had persistent and distressing AVH, and a diagnosis of a schizophrenia-spectrum disorder. RT was delivered over a maximum of 16 sessions within 5 months. Blind assessments were conducted at baseline, at 5 and 9 months. Feasibility outcomes were the numbers of patients recruited and retained, safety and therapist adherence. The primary endpoint was the distress factor score of the AVH-subscale of the Psychotic Symptoms Rating Scales at 9 months. Results Eighty-five of 177 enrolled participants were randomised into RT+TAU (n=43) or TAU (n=42). Feasibility was excellent with 87% retention at 9 months, 86% reaching ‘treatment uptake’, 98% therapist adherence and no unexpected serious adverse reactions. Compared to TAU, RT+TAU showed non-significant trends towards less AVH-distress (b=-2.40, SE=1.52, p = 0.121, 90% CI (-4.94 to 0.15) and stronger improvement on all but one secondary outcomes. Conclusion A randomised controlled trial of RT is feasible, safe, and well accepted. Our results provide an encouraging basis to further test the efficacy of RT in a definitive multicentre trial.