Mahdavinasab 2019.

Study characteristics
Methods	10‐week parallel trial of baclofen versus placebo
Participants	Inclusion criteria: children 4–12 years meet the DSM‐V criteria for diagnosis of ASD have had irritability symptoms of at least moderate severity, defined as scores ≥ 12 on the ABC‐I subscale Exclusion criteria: children who were not deemed of sufficient severity to be treated with risperidone children who had had concomitant psychiatric disorders, (pre‐existing medical or disease conditions especially epilepsy or seizure disorders) severe intellectual disability history of alcohol/drug abuse, tardive dyskinesia, or history of antipsychotic medication or behavior therapy within the 6 months prior to the trial trial Location/setting: children’s outpatient clinic at a tertiary hospital in Iran Mean IQ: details not provided Mean age: baclofen + risperidone 8.04 (SD = 2.33); placebo + risperidone 7.9 (SD = 2.0) Gender: 46 male, 12 female Sample size: baclofen (2); placebo (32). Number analysed: baclofen (29); placebo (29) Reasons for dropouts: baclofen (3), physician's choice (1), refusal of further therapy (2); placebo (3), refusal of further therapy (3) Baseline ABC‐I or other BoC scale: ABC‐I baclofen + risperidone 22.76 (8.56); placebo + risperidone 22.62 (9.24) Timing of outcome assessments: baseline, week 5, week 10 Concomitant medications: details not provided Previous medications: excluded if history of antipsychotic medication within the past 6 months before enrolment.
Interventions	Baclofen + risperidone: initial dose of 0.5 mg and stepwise 0.5 mg weekly increases for the first 3 weeks + 0.6 mg kg; 1 baclofen 3 times/day Risperidone: initial dose of 0.5 mg and stepwise 0.5 mg weekly increases for the first 3 weeks + placebo
Outcomes	Primary outcomes: irritability (Aman 1985) AEs Secondary outcomes: tolerability
Notes	Study start date: April 2016 Study end date: August 2018 Funding: "This study was supported by a grant from Tehran University of Medical Sciences to Prof. Shahin Akhondzadeh (Grant No: 32601)". Conflicts of interest" "Authors declare no conflict of interest". Trial registry: IRCT201701131556N95
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomization was performed by a randomization operator who was not otherwise involved in this trial."
Allocation concealment (selection bias)	Low risk	Quote: "Randomization codes were kept secure until data curation was completed."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind. "Randomization codes were kept secure until data curation was completed... Participants and their parents were blinded to group allocations."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Double‐blind. "Randomization codes were kept secure until data curation was completed... No specific details about outcome assessors."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low attrition and all participants were accounted for
Selective reporting (reporting bias)	High risk	Trial reg lists additional primary outcome not reported: Childhood autism rating scale (CARS)
Other bias	High risk	The contact author is also on the ethics committee at the university funding the study. The contact author is a peer‐reviewer for one of the journals in which some of their studies are published.