Naeem 2005.

Methods	Allocation: randomised. Design: multi‐centre (6 sites, Belfast, Glasgow, Hackney, Newcastle, Southhampton and Swansea). Duration: 3 months. Setting: inpatients and community. Location: Southhampton and Newcastle‐upon‐Tyne, UK.
Participants	Diagnosis: 100% ICD‐10 schizophrenia with co‐occurring mild to moderate substance abuse according to HoNOS Item 3* (alcohol 74%, drug use problem 26%**). N = 105. Age: 18 ‐ 65 years. Sex: 87 M, 18 F. Ethnicity: 90% Caucasian. Inclusion criteria: patients with schizophrenia, age 18‐65 years; receiving treatment within mental health services.
Interventions	1. Psychosocial intervention: CBT plus psycho‐education: 6 sessions over 3 months and carers offered 3 sessions along with carer‐oriented information. N = 67.*** 2. Standard care: Routine care. N = 38.
Outcomes	Leaving the study early: lost to treatment. Mental state: Insight Scale. Unable to use Substance use: HoNOS item 3 (data skewed). Mental state: BSA, SCR, CPRS, MADRS (all data skewed). Other: HoNOS ‐ general functioning (data skewed).
Notes	ITT analysis. *Patients were excluded if they met a diagnosis of drug or substance misuse dependence. **Based on those participants who provided details (n = 70/105). ***There was a 2:1 ratio to include more participants into the CBT arm.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised; random numbers computer‐generated/sealed envelopes stratified by site. Ratio of 2:1 for CBT:TAU.
Allocation concealment (selection bias)	Unclear risk	Sealed envelopes opened at the time of treatment allocation. Unclear if envelopes were sequentially numbered and opaque.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Clinician‐/participant‐mediated and participants and personnel not blinded. It is not possible to blind a psychosocial intervention.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Raters blind to treatment allocation.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Lost to follow‐up: 14% (15/105) at 3 months. No reasons are given for withdrawals; 10 participants dropped out of treatment versus 5 participants from TAU. Missing values were imputed for full ITT analysis but can have unclear bias effects.
Selective reporting (reporting bias)	Unclear risk	Insufficient information to permit judgement of 'yes' or 'no' as no protocol was available.
Other bias	Low risk	No evidence other bias occurring.