Malla 2017.

Study characteristics
Methods	Study design: Individually‐RCT Duration: 36 months extension of SEI. Two‐year duration standard SEI (prior to trial) is followed by three‐year extension of ESEI (in intervention arm). Total SEI plus ESEI duration was five years Setting: community‐based mental health team, Canada Recruitment method: all patients receiving treatment for first‐episode psychosis in an early intervention service of the McGill University Network following an 18‐month clinic review
Participants	Diagnosis: majority diagnosed with a primary diagnosis of schizophrenia spectrum disorder, n = 143 (65%) Sample size: 220 participants randomised Age: mean age of onset 22.4 (SD = 4.4) years of age Sex: 68.6% male Inclusion criteria: having completed 24 months (plus or minus 3 months) of treatment in SEI services. DSM‐IV criteria for a psychotic disorder (schizophrenia spectrum psychoses or affective psychosis). Exclusion criteria: inability to provide informed consent or to speak either English or French fluently, and an IQ below 70 as assessed using the short form of the Wechsler Adult Intelligence Scale
Interventions	Extended SEI (n = 110) consisted of: an extra 3 years (following 2 years of SEI) of modified assertive case management (caseload 20‐22 cases per case manager); lowest effective dose pharmacotherapy relapse prevention strategy; family counselling (multiple family intervention and psychoeducation for families); CBT (in patients with a major depressive episode, anxiety disorder or residual psychotic or negative symptoms); substance abuse education and monitoring. Standard SEI + TAU consisted of discharge to a primary care physician or transfer to a standard community mental health team
Outcomes	Recovery ‐ used remission as proxy ‐ defined as the proportion in remission judged by SAPS < 2 and SANS < 2 for a three‐month period Disengagement ‐ those who completed all research assessments as per their protocol were considered to have not disengaged Negative psychotic symptoms ‐ SANS (skewed) Leaving the study early Death by suicide or natural causes
Notes	Funding source: Canadian Institutes of Health Research (grant MCT 94189; registration CCT‐NAPN‐18590). Conflicts of interest: A Malla is supported by the Canada Research Chairs Program
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Centralised and computerised randomisation Quote: "...were allocated to either the experimental or the control intervention using a computerized urn randomisation protocol carried out by a trial statistician not connected with any of the services".
Allocation concealment (selection bias)	Low risk	Quote: "Group allocation was concealed in sealed opaque envelopes".
Blinding of participants and personnel (performance bias) All outcomes	High risk	Intervention not blinded. Primary outcome subjective measure, with repeated assessments every three months. Assessors blinded, but a third participants unblinded during trial.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Assessors blind to treatment allocation, not involved in patient's care or have access to patients' clinical notes but 49/154 patients lost their blind assessment status as patients inadvertently revealed their treatment group
Incomplete outcome data (attrition bias) All outcomes	High risk	Higher attrition rate for TAU (51.8%) compared with extended SEI (20.9%). Tried to account for this by obtaining additional data from clinical files across all services, however, the quality of records "was likely better in the extended SEI"
Selective reporting (reporting bias)	Low risk	The published protocol does not differ to the published outcomes
Other bias	Low risk	None detected