ISRCTN65314790.

Study characteristics
Methods	Allocation: randomised Blindness: single Duration: over 7 sessions (1 introductory session + 6 therapy session) weekly 50 minutes each Design: cross‐sectional Country: UK
Participants	Diagnosis: primary diagnosis of schizophrenia spectrum (ICD10 F20–29) or affective disorder (F30–39 with psychotic symptoms N = 150 Age: mean about 43 years, range 18–65 years Sex: men and women Setting: South London and Maudsley NHS Trust, sites remote from the clinic History: enduring auditory verbal hallucinations during previous 12 months despite continued treatment
Interventions	1. Avatar Therapy: participants created a computerised representation of the entity that they believed was the source of their main voice and then the team set up the avatar in an introductory session, which included a comprehensive assessment of the voice(s) and included verbatim content. 10–15 minutes of each session involved face‐to‐face work with the avatar, where in the therapist facilitated a direct dialogue between the participant and the avatar. Participants sat in 1 room facing their avatar on a computer monitor. The therapist sat in a second room with a control panel that allowed them to speak in his or her own voice, or as the avatar. N= 75. 2. Supportive counselling: a manual‐based, face‐to‐face supportive counselling approach adapted with permission from that employed by the SoCRATES Trial Group delivered by graduate assistant psychologists who were recruited on the basis of extensive experience of working therapeutically in a psychosis context. N= 75.
Outcomes	Mental state – general: PSYRATS total Mental state – specific (insight): BAVQ‐R total, VAAS acceptance, VPDS voice power, VPDS total Mental state – specific (depression and anxiety): CDS, DASS‐21 total, Psychotic Symptom Rating Mental state – specific (negative symptoms): SANS Leaving study early: any reason, specific reasons Quality of life: MANSA, Rosenberg Self‐Esteem Scale Unable to use Mental state – specific (positive): SAPS (skewed data) Physiological measures – not protocol outcomes Satisfaction: RRPQ (data not reported by group)
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Participants were randomly assigned (1:1) to receive AVATAR therapy or supportive counselling with randomised permuted blocks (block size randomly varying between two and six". Comment: low risk
Allocation concealment (selection bias)	Low risk	Quote: "independent web‐based service provided by the UKCRC [UK Clinical Research Collaboration] Registered Clinical Trials Unit at King's College London (registration number 053) to maintain allocation concealment". Comment: low risk
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "assessors" Comment: unclear risk
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "All assessments were done by research assessors who were masked to therapy allocation. To avoid unmasking, we ensured that assessors did not have access to clinical records after the baseline (pre‐randomisation) assessment or access to the therapy database at any stage, that all assessments were done at sites remote from the clinic, and that participants were reminded before each assessment not to disclose their allocation." Comment: low risk
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: no clear information about the adverse events, RRPQ and Air. Comment: high risk
Selective reporting (reporting bias)	Unclear risk	All important outcomes have been reported but a few of the outcomes in registered protocol have not been reported in final report of the trials. Comment: unclear
Other bias	High risk	Quote: "one of authors is part funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London. Two of the authors declared patents pending on the avatar system. The funding source had no input in the preparation of this manuscript". Quote: "significantly greater improvement" used frequently and confusing information in the CONSORT flow diagram. Comment: high risk