Amiri 2019.

Study characteristics
Methods	Study type: RCT Design: 2‐arm, parallel group design Blinding: not blinded
Participants	Sample: adults with insomnia disorder based on the criteria in the second edition of the International Classification of Sleep Disorders n: 30 randomised, 30 completed and included in analyses Age: mean 27 (SD 2.5) years Sex: 30 men, 0 women Setting: participants' homes + 1 live session per week Country: Iran
Interventions	Intervention (n = 15): music group. Participants listened to researcher‐selected Persian music administered themselves at home. The listening device was not reported. Music characteristics: the music included the Dastgahs of Nava and Bayat‐e Esfahan. The instruments used for playing were setar, tar, tonbak, kamancheh, oud and daf. The recorded music included songs from the works of Mohammad Reza Shajarian, Parviz Meshkatian, Hossein Alizadeh, Hossein Behroozinia, Ali Pajooheshgar, Masoud Shaari, Mohammad Reza Lotfi, Faramarz Payvar, Alireza Eftekhari, Salar Aghili, Amir Motavalli, and Gholam Hossein Banan. Length of sessions: 60 minutes Frequency of sessions: daily between 10 pm and 11 pm Duration of intervention period: 6 weeks (42 days) Control (n = 15): waitlist
Outcomes	Sleep quality (assessed with PSQI) mean (SD) at baseline and postintervention Insomnia severity (assessed with ISI) mean (SD) at baseline and postintervention Anxiety (assessed with DASS‐21) mean (SD) at baseline and postintervention Depression (assessed with DASS‐21) mean (SD) at baseline and postintervention
Notes	Trial start and end dates: no information provided Funding sources: sponsored by Kermanshah University of Medical Sciences, Iran Protocol registration: Iranian Registry of Clinical Trials (IRCT2017040425817N3)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "30 patients (mean age: 27) were enrolled and randomly assigned to the intervention (N = 15) and control (N = 15) groups." (Amiri 2019, p 2). Comment: no information on randomisation method.
Allocation concealment (selection bias)	Unclear risk	Comment: no information on randomisation procedure or measures taken to conceal allocation.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: not possible to blind participants to the music intervention.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Comment: no blinding of outcome assessors.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no attrition and no indication of missing data.
Selective reporting (reporting bias)	Low risk	Comment: results reported corresponded to protocol.
Other bias	Low risk	Comment: no indication of other risk of bias.