Durham 2003.

Methods	Allocation: randomised Blinding: assessor blind Location: two adjacent mental health services in Tayside and Fifemental health services in Tayside and Fife, Scotland Length of follow‐up: 6 years
Participants	Diagnosis: schizophrenia (n = 36); schizoaffective disorder (n = 5); delusional disorder (n = 2); (ICD‐10 and DSM‐IV) N = 43* Sex: 30 M, 13 F Age: mean ˜ 36 years, SD ˜ 10 years Included: length of illness: 2 ‐ 31 years; aged 16 ‐ 65 years who are known to the psychiatric services as experiencing positive symptoms, symptoms of persistent and distressing hallucinations or delusions, or both, and who have been stabilised on anti‐psychotic medication for at least a 6‐month period with medication under the care of a consultant psychiatrist Excluded: primary diagnosis of alcoholism or drug misuse, evidence of alcoholism or drug misuse, evidence of organic brain disease and history of violence
Interventions	1. CBT** group: N = 22 Content: an initial emphasis on engagement, education and building a therapeutic alliance; functional analysis of key symptoms, leading to a formulation and problem list; development of a normalising rationale for the participant's psychotic experiences; exploration and enhancement of current coping strategies; acquisition of additional coping strategies for hallucinations and delusions; and focus on accompanying affective symptomatology using relaxation training, personal effectiveness training and problem‐solving, as appropriate Delivered by: five clinical nurse specialists with extensive professional experience of severe mental disorder. The therapists received training mainly focused on CBT. Frequency: 20 therapy sessions of approximately half an hour in length over a 9‐month period Treatment duration: 9 months 2. Standard care** group: N = 21 Content: participants received the usual care provided by the psychiatric services in Tayside and Fife. Services are well developed in these two areas, with a focus on community care delivered by community mental health teams. Services include regular psychiatric consultation and contact with a key worker (typically a trained community psychiatric nurse), with emergency assessment and hospital admission available as required. Facilities in the community include day care, sheltered work, supported accommodation and volunteer befriending. Delivered by: not reported Frequency: not reported Treatment duration: 9 months
Outcomes	Mental state: clinically important change (no improvement, defined as 50% decrease in symptom severity on PANSS scale), general (PANSS total scores); hallucinations, delusions (PSYRATS score) Functioning: general (GAF scores) Satisfaction with treatment: leaving the study early Unable to use: Participants attitude to treatment (not validated scale, but the participants' response to a series of questions) Self‐report measures of symptom severity, self‐esteem, and attitude to illness (data not reported)
Notes	* We only used data from two arms: CBT plus standard care and standard care. ** The term "TAU" was used in this paper. * Participants in CBT group also received the standard care intervention.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The randomisation procedure (sealed envelope technique) was devised by the project statistician and administered centrally by the non‐clinical project coordinator. It was carried out separately within each treatment centre using randomised permuted blocking." (p.303) Comments: The author described a random component in the sequence generation process.
Allocation concealment (selection bias)	Low risk	Quote: "The randomisation procedure (sealed envelope technique) was devised by the project statistician and administered centrally by the non‐clinical project coordinator. It was carried out separately within each treatment centre using randomised permuted blocking." (p.304) Comments: Participants and investigators enrolling participants could not foresee assignment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Patients also were asked not to mention any details of their treatment during post‐treatment assessment..." (p.304). Comments: Participants were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Outcome evaluation by an independent assessor, an experienced psychiatrist, blind to treatment allocation at post‐treatment and 3‐month follow‐up." (p.304) Comments: The outcome assessor could not foresee the treatment allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "There was a relatively small amount of missing data at post‐treatment (9%) and follow‐up (14%). The analyses were repeated with the missing values replaced either with previous values carried forward or with group means, and the same pattern of significance was found." (p.307) Comments: It seemed unlikely to cause attrition bias.
Selective reporting (reporting bias)	High risk	Quote: "Self‐report measures were administered to assess symptom severity, self‐esteem and attitude to illness, but these are not reported." (p.304) Comments: Self‐report measures were not reported.
Other bias	Low risk	Comments: none obvious