Neppe 1983.

Methods	Allocation: randomised ‐ no further information. Blinding: double ‐ no further information. Design: cross‐over. Duration: 2 X 6 weeks (preceded by 3‐week baseline). Setting: in hospital.
Participants	Diagnosis: schizophrenia (10), non‐progressive dementia (2), rapid cycling (1) (diagnostic criteria unclear). N = 13.* Age: mean ˜34 years. Sex: 8 M, 5 F. History: chronic, "poor‐responders", EEG abnormalities.
Interventions	1. Adjunctive carbamazepine: dose 600 mg/day + various antipsychotics (constant dose). N = 3. 2. Placebo adjunctive treatment + various antipsychotics (constant dose). N = 6.
Outcomes	1. Leaving the study early. 2. Global impression (CGI). 3. Mental state (20%, 35%, 50% BPRS reduction). Unable to use: . General improvement (Global Assessment, OCR unpublished scales).
Notes	*Data extracted for 9 participants with schizophrenia from published data.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomized" (p.326), "random number list" (letter).
Allocation concealment (selection bias)	Unclear risk	No information available.
Blinding of participants and personnel (performance bias) Objective outcomes	Low risk	"Double blind" (p.326).
Blinding of participants and personnel (performance bias) Subjective outcomes	Unclear risk	"Double blind" (p.326).
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	"Double blind" (p.326).
Blinding of outcome assessment (detection bias) Subjective outcomes	Unclear risk	"Double blind" (p.326).
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	"Two out of six patients in the control group compared to zero out of three in the intervention group dropped out [out of 13]" (p.327).
Selective reporting (reporting bias)	High risk	No SDs for BPRS.
Other bias	Low risk	No other bias ("one [subject had] a history of contaminating cannabis use", p.327).