Chen 2012.

Methods	Allocation: parallel, randomised Blind: not stated Setting: hospital (inpatient and outpatient), single centre Country: China Length of study: 12 weeks
Participants	Diagnosis: treatment‐resistant schizophrenia (CCMD‐3) Total N at randomisation = 71 Sex: male 39, female 32 Age (years): mean 31.88, SD 9.2 Length of illness (years): mean 16.1, SD 11.6 Inclusion criteria: failure after 3 types of antipsychotics (at least 2 types of antipsychotics with different chemical structure; equivalent dose of chlorpromazine more than 600 mg/d, each drug used more than 6 weeks, no significant improvement or response) over the last 5 years; social adaptation dysfunction: PANSS score > 60. Exclusion criteria: people with severe physical or brain illness; alcohol or drug abusers.
Interventions	ECT group (n = 36): MECT + clozapine Content: the mean dose of clozapine was 275 ± 25 mg/d when combined with MECT. The dosage of clozapine was 1/2 to 2/3 times that of 'clozapine alone' group. The ECT device was Thymatron. Participants did not receive benzodiazepines, antiepileptic drugs, haloperidol, or other treatment. Frequency: for MECT, 3 times a week (for first 3 weeks), then twice a week for the other weeks; not stated for clozapine Course of treatment (MECT): 12 sessions Treatment duration: 12 weeks Control group (n = 35): Clozapine alone Content: the mean dose of clozapine was 355 ± 65 mg/d. Frequency: not stated Treatment duration: 12 weeks
Outcomes	Response to treatment: clinically significant response to treatment* Mental state: assessed by PANSS Adverse events
Notes	*Clinically significant response assessed by the reducing score rate of PANSS: 1) cure: reducing rate ≥ 75%; 2) significant improvement: reducing rate between 50% and 75%; 3) improvement: reducing rate between 25% and 49%; 4) no clinical response: reducing rate < 25%. The clinically significant response to treatment defined as cure + significant improvement. Contact information: Shihezi Oasis Hospital, Shihezi, Xinjiang, China
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...were divided randomly into two groups..." (p.58) Comments: The author described a random component in the sequence generation process, but no details were provided on randomisation method.
Allocation concealment (selection bias)	Unclear risk	Comments: The author did not describe the allocation concealment. Insufficient information to permit judgement of 'low risk' or 'high risk'.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comments: The participants and personnel could not be blinded as 1 group did not use ECT, and no sham‐ECT was used.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comments: The author did not describe the blinding of outcome assessment. Insufficient information to permit judgement of 'low risk' or 'high risk'.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comments: No missing outcome data.
Selective reporting (reporting bias)	Low risk	Comments: The protocol is not available; all outcomes stated in methods reported in results.
Other bias	Low risk	None obvious.