Case series design with participants with psychosis with a history of interpersonal trauma/abuse and current distressing auditory verbal hallucinations and dissociative experience. Participants were offered up to 24 therapy sessions over a 6-month intervention window.

Objectives: Previous studies have suggested that dissociation might represent an important mechanism in the maintenance of auditory verbal hallucinations (i.e., voices) in people who have a history of traumatic life experiences. This study investigated whether a cognitive behavioural therapy (CBT) intervention for psychosis augmented with techniques specifically targeting dissociative symptoms could improve both dissociation and auditory hallucination severity in a sample of voice hearers with psychosis and a history of interpersonal trauma (e.g., exposure to sexual, physical, and/or emotional abuse).

Design: Case series.

Methods: A total of 19 service users with psychosis were offered up to 24 therapy sessions over a 6-month intervention window. Participants were assessed four times over a 12-month period using measures of dissociation, psychotic symptoms severity, and additional secondary mental-health and recovery measures.

Inclusion Criteria:

1. Be in contact with mental health services.
2. Have an identified care coordinator.
3. Meet ICD-10 criteria for schizophrenia, schizoaffective disorder or delusional disorder or meet entry criteria for an Early Intervention in Psychosis service in order to allow for diagnostic uncertainty in early phases of psychosis.
4. History of voice-hearing for a minimum of six months.
5. Aged 16 and above.
6. Score ≥ 2 (i.e. "Voices occurring at least once a day") on the frequency item of the PSYRATS.
7. Score ≥ 3 (i.e. "Voices are very distressing, although subject could feel worse") on the distress intensity rating of the PSYRATS.
8. Confirmed that they consider AVHs, dissociative experiences, and/or trauma as their main problem or presenting difficulty, and that would like to receive a psychological intervention specifically designed to address these difficulties - this will be assessed using four items integrated in the PSYRATS interview administered as part of the present study, and the self-reported therapy goals generated through the CHOICE short form.
9. Score ≥ 1 on any of the items of the Bref Betrayal Trauma Survey assessing lifetime exposure to interpersonal trauma (i.e. items 3-11).
10. scores suggestive of clinical levels of dissociative symptoms, as indicated by a score > 20 on the Dissociative Experiences Scale, time bound
11. Capacity to provide informed consent.
12. Judged by their clinician to be clinically stable for the preceding 4 weeks

Exclusion Criteria:

1. Any person without capacity to provide written informed consent.
2. If the experience of voices/psychosis is organic in origin (for example, hallucinatory experiences linked to traumatic brain injuries, organic psychoses, or emerging in the context of dementing conditions).
3. Insufficient command of English to complete the research interviews and measures.
4. Intellectual disability, or severe cognitive dysfunction that might preclude the individual's ability to provide informed consent, understand the study procedure and/or fully appreciate the potential consequences of their participation.
5. Primary diagnosis of substance misuse dependency.
6. Where care coordinators identify reasons for why participation might be potentially detrimental.
7. Inpatient/acute care needed.