Huang 1987.

Methods	Randomisation: randomised, no further details Blinding: double, no further details Duration: 11 weeks; 2 weeks non‐randomised single‐blind run in phase and 9 weeks randomised double‐blind phase. Design: parallel Location: single‐centre (USA) Setting: inpatients
Participants	Diagnosis: schizophrenia (DSM III); treatment resistant. N = 50 Gender: not indicated Age: 21 to 55 years History: mentally ill for 2 years or more; treated with 2 or more antipsychotics at usual therapeutic doses (equivalent to thiothixene 60 mg/day) for 6 months or more without appreciable remission.
Interventions	All participants firstly received single‐blind thiothixene 60 mg/day for 2 weeks to confirm treatment resistance e.g. not showing moderate improvement during the first 3 weeks of treatment. Participants were then randomised to either: 1. dose increase: thiothixene up to 400 mg/day. N = 25; or 2. dose maintenance: thiothixene 60 mg/day. N = 25. Rescue medication: benztropine; no further details.
Outcomes	Global state: clinically relevant response (defined as moderate improvement in Roerig Global Scale (RGS) (Guy 1976)) Leaving the study early (due to adverse events, any reason and inefficacy) Mental state (BPRS total score, BPRS factors such as anxiety‐depression, anergia, thought disturbance, activity, hostility‐suspicion), Nurses Observation Scale for Inpatient Evaluation (NOSIE total score, NOSIE factors such as social competence, social interest, personal neatness, irritability, manifest psychosis, retardation, depression). Adverse effects (side effect check list, dystonia, dry mouth, blurred vision, drowsiness, orthostatic hypotension, tremor, dizziness, drooling, constipation, ataxia, akathisia, palpitations, headache, premature ventricular contractions). Unable to use: Vital signs (CBC, urinalysis, SMA‐12, ECG, blood pressure, pulse rate); no data were presented and not protocol outcomes.
Notes	50 participants were randomised. Eight of the 50 participants (4 in each group) showing moderate improvement on the RGS in the first 21 days were eliminated from the study as they were not considered to be treatment‐resistant.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...randomly assigned..." (pg. 70); no further details
Allocation concealment (selection bias)	Unclear risk	No details were presented
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote: "...under double‐blind control to..." (pg. 70); no further details
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "...under double‐blind control to..." (pg. 70); no further details
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear whether all those who left early were reported. It may be that 26% (13/50) left the study early.
Selective reporting (reporting bias)	High risk	No usable data on vital signs were reported in the results
Other bias	Low risk	No obvious risk for other bias