Avatar-mediated Therapy Versus Cognitive Behavioural Therapy for Persisting Experiences of Hearing Voices

Auditory verbal hallucination severity, measured by total score on the Psychotic Symptom Rating Scale - Auditory Hallucinations Scale (PSYRATS-AHS)

Clinician-rated scale providing an index of overall severity based on 11 aspects of hallucinations (frequency, duration, intensity of distress, etc.), rated masked to treatment allocation. Each of the 11-items are scored on a 5-point scale (0 - 4), scores range from 0 to 44, with increased symptom expression indicated by higher scores.

Change in auditory verbal hallucination severity, measured by total score on the Psychotic Symptom Rating Scale - Auditory Hallucinations Scale (PSYRATS-AHS) over follow-ups

Follow-up timepoints on the clinician rated scale that is used to measure the primary outcome. Includes 11-items that are scored on a 5-point scale (0 - 4), scores range from 0 to 44, with increased symptom expression indicated by higher scores.

Change in auditory verbal hallucination-related distress, measured by the Psychotic Symptom Rating Scale - Auditory Hallucinations Scale (PSYRATS-AHS) Distress Score

Subscale of the clinician-rated scale that is used to measure the primary outcome. This includes 1-item that is scored on a 5-point scale (0 - 4), score ranges from 0 to 4, with increased symptom expression indicated by a higher score.

Remission of hallucinations, indexed by a score below 3 on the Hallucination scale of the Positive and Negative Syndrome Scales (PANSS)

Clinician-rated scale to assess presence and severity of hallucinations. This includes 1-item, scored from 1 to 7, with increased symptom expression indicated by higher scores.

Change in overall psychosis symptom severity, measured by Positive and Negative Syndrome Scales (PANSS) total and sub scale scores

Clinician-rated scale to assess overall psychotic symptom severity on total and sub scale scores (Positive, Negative and General Psychopathology). Includes a total of 30-items that are scored on a 7-point scale (1 - 7). Total score ranges from 30 to 210; Positive and Negative sub scale scores range from 7 to 49; General Psychopathology sub scale scores range from 16 to 112. Higher scores are indicative of increased symptom expression.

Satisfaction with therapy, measured by the Client Satisfaction Questionnaire (CSQ-8)

The 8-item Client Satisfaction Questionnaire (CSQ-8) will be administered at the end of treatment to assess and compare participants satisfaction across the two therapies. In addition, a group of participants will be purposively sampled to be invited to take part in a detailed semi-structured qualitative interview (conducted by a non-blinded researcher) about their experiences of the intervention.

Adverse effects of therapy

Negative psychological effects such as discomfort and anxiety that are relevant to tolerability will be measured using the Negative Effects Questionnaire (NEQ), a 32-item psychometrically validated questionnaire developed for monitoring adverse effects of psychological therapies. The NEQ items are scored on a 5-point Likert scale (0-4) and differentiates between negative effects attributed to treatment and those caused by other circumstances. Potential deterioration in AVHs will be reported for each group by the proportion of participants showing deterioration above a reliable change index for the PSYRATS. Serious adverse events (SAEs) will include participant death, hospital admissions, episodes of crisis, assessment team treatment, attempted suicide, and violent incidents leading to police involvement; these will be recorded systematically.

Cost-effectiveness

Cost-effectiveness calculations will use the Assessment of Quality of Life - 8 Dimensions (AQoL-8D) to measure quality of life as an index of utility, expressed in quality-adjusted life years (QALYs). The AQoL-8D includes 35-items covering 8 dimensions: Independent Living, Pain, Senses, Mental Health, Happiness, Coping, Relationships, and Self-worth. To both measure treatment as usual (TAU) and determine broader treatment costs, a Resource Use Questionnaire (RUQ), adapted for use in this population, will be used. Consent for administrative data (e.g., Medicare and Pharmaceutical Benefits, MBS/PBS) will also be collected. Prescribed medication will be considered in terms of both cost and chlorpromazine -equivalent antipsychotic medication dose.

Change in the impact of AVHs, measured by the Voice Impact Scale (VIS)

Self-report measure of the degree of impact of hearing voices on domains of distress, interference with day-to-day functioning, and positive impacts. Includes 24-items. Each item is individually scored from 0 (disagree completely) to 10 (agree completely) with higher scores on individual items indicating higher agreement with the items listed experience. Not applicable is also available if the item is not relevant.