Freeman 2015.

Methods	Allocation: randomised Blinding: assessor blind Location: two UK centres Length of follow‐up: 24 weeks
Participants	Diagnosis: schizophrenia (n = 111); schizoaffective disorder (n = 11); other (n = 28) N = 150 Sex: 86 M, 64 F Age: mean ˜ 40.9 years, SD ˜ 10.5 years Included: length of illness: not reported; a current persecutory delusion; scoring at least 3 on the conviction scale of the PSYRATS; the delusion had persisted for at least three months; negative beliefs about the self as indicated by endorsing at least one negative schematic belief on the Brief Core Schema Scale (BCSS); aged between 18 and 70 years; and where major changes in medication are being made, entry to the study would not occur until at least a month after stabilisation of dosage Excluded: a primary diagnosis of alcohol or substance dependency or personality disorder; an organic syndrome or learning disability; a command of spoken English that was inadequate for engaging in therapy; and currently having individual CBT
Interventions	1. CBT group*: N = 73 Content: The main techniques were psychoeducation about worry, identification, and reviewing of positive and negative beliefs about worry, increasing awareness of the initiation of worry and individual triggers, use of worry periods, planning activity at times of worry (which could include relaxation), and learning to let go of worry. Delivered by: not stated Frequency: six sessions over 8 weeks Treatment duration: 8 weeks 2. Standard care group: N = 77 Content: Standard care was delivered according to national and local service protocols and guidelines. This usually consists of prescription antipsychotic drugs, visits from a community mental health worker, and regular outpatient appointments with a psychiatrist. Delivered by: not reported Frequency: nor reported Treatment duration: 8 weeks
Outcomes	Mental state: general (PANSS, CHOICE scores), delusions (PsyRATS scores), distress (PsyRATs scores) , paranoia (GPTS scores), worry, (PSWQ scores), rumination (PTQ scores), well‐being (WEMWS scores) Satisfaction with treatment: leaving the study early
Notes	*Participants in the 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: "We used a web based randomisation system, written by the Oxford Clinical Trials Unit for Mental Illness." (p.306) Comments: Randomisation was adequate.
Allocation concealment (selection bias)	Unclear risk	Comments: The author did not address this information.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "The assessors were masked to patients' treatment allocations, but all patients were informed of their allocation by a trial therapist." (p.306) Comments: blinding of participants not ensured
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The assessors were masked to patients' treatment allocations, but all patients were informed of their allocation by a trial therapist." (p.306) Comments: The outcome assessor could not foresee assignment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comments: 5 participants from the intervention group and 4 from the control group left the study early, however, an intention‐to‐treat analysis was used.
Selective reporting (reporting bias)	Low risk	Comments: All measured outcomes were reported.
Other bias	Low risk	Comments: none obvious