Kemp 2007.

Methods	Allocation: randomised. Design: single‐centre. Duration: 6 months. Setting: community based early intervention programme. Location: Western Sydney, NSW, Australia.
Participants	Diagnosis: DSM‐IV psychotic illness and current alcohol or cannabis use based on AUDIT or DAST scores. N = 19. Age: mean ˜ 21 years, range 17‐25 years. Sex: 13 M, 3 F (3, Unknown). Ethnicity: not stated. Inclusion criteria: young English speaking, living within the area health sector and not homeless.
Interventions	1. Psychosocial intervention: MI + CBT, Stop using stuff (SUS) manualised 4‐6 hours. N = 10. 2. Standard care: TAU, standard care included case management and has a significant focus on substance reduction. N = 9.
Outcomes	Leaving the study early: lost to evaluation. Mental state: PANSS total. Unable to use Mental State: DASS (some data skewed). Substance use: AUDIT, DAST‐10 frequency and quantity of cannabis or alcohol use (skewed data).
Notes	Authors have kindly provided additional data.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomised, cards were shuffled, numbered and placed in sealed envelopes.
Allocation concealment (selection bias)	Unclear risk	Numbered sealed envelopes with the allocation placed into a box by a third person. Envelopes were then drawn in order from the box each time a patient was randomised. Unclear whether envelopes were 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	High risk	Measures that were clinician‐rated were all performed by the clinician providing the treatment and were therefore not blinded.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Lost to follow‐up: 16% (3/19) 6 months. Three patients dropped out of the TAU group, no explanation was given. No ITT analysis.
Selective reporting (reporting bias)	Unclear risk	Insufficient information to permit judgement of 'yes' or 'no' as no protocol was available.
Other bias	Unclear risk	Had extreme baseline imbalance in substance use (AUDIT), DASS and self‐efficacy score. This could be due to low subject numbers recruited for study.