Tang 1994.

Methods	Allocation: randomised ‐ no further details. Blindness: single ‐ assessor blinded. Duration: 1 month. Design: parallel group.
Participants	Diagnosis: residual schizophrenia (DSM‐III‐R). History: unknown. N = 76. Age: not reported. Sex: not reported. Setting: inpatients.
Interventions	1. Active and receptive large‐group music therapy (music listening, singing and playing on instruments, discussion), 1 hour per session, 5 sessions per week (on average 19 sessions in total). N = 38. 2. Standard care (medication only). N = 38.
Outcomes	Mental state, negative symptoms: Scale for the Assessment of Negative Symptoms (SANS; Andreasen 1982). Unable to use ‐ insufficient data: Disability Assessment Schedule (DAS).
Notes	Author unable to provide additional data. Music therapy was conducted by clinicians (doctor, nurses) with limited training.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details given.
Allocation concealment (selection bias)	Unclear risk	No details given.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Due to the nature of the intervention it was not possible to blind those who received music therapy or those who delivered it.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Nurses who did the SANS and DAS assessment for participants were blinded to treatment status.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All 76 participants completed the trial.
Selective reporting (reporting bias)	Unclear risk	No study protocol available. All outcome measures described in the study were considered in the analysis.
Other bias	Unclear risk	Adequate music therapy method: yes. Adequate music therapy training: unclear (one doctor and two nurses conducted the music therapy. Two of them attended a two‐week music therapy course). No financial, personal or other interests producing bias detected.