Mace 2001.

Study characteristics
Methods	Parallel trial of haloperidol versus placebo
Participants	Inclusion criteria: admitted to an inpatient unit for the treatment of self‐injurious behaviour (SIB) aged 4.5‐31.8 years diagnosed with intellectual disabilities Exclusion criteria: acute medical illness contributing to the SIB [self‐injurious behaviour] use of psychotropic medications during the trial Location/setting: inpatient unit in the USA Sample size: 7 in total who had autism Number of withdrawals/dropouts: none reported Gender: 3 male, 4 female Mean age: 11 years IQ: details not reported Baseline ABC‐I or other BoC: self‐injurious behaviour per hour at baseline, haloperidol 125; placebo 146.4 Concomitant medications: participants were not permitted to take psychotropic medications during the trial. History of previous medications: "participants were taking zero to three psychotropic medications upon admission to the inpatient unit. These medications were discontinued before completion of the functional analysis (except for Subjects 5 and 9), and individuals remained off these medications throughout the remainder of the study."
Interventions	Intervention: (haloperidol) for minimum 34 days: "started at 0.025 mg/kg/day for people weighing below 20 kg or 0.5 mg/day for those above 20 kg. The doses were titrated up to the maximum of the lower dose of 0.1 mg/kg/day or 4 mg/day, or until there was a 75% decrease in SIB or significant side effects to the medication. Individuals who did not have a positive response to haloperidol were weaned from the medication by decreasing the total daily dose by 0.25‐0.5 mg every 3‐5 days until the individual was off the medication. Once the haloperidol was stopped, a placebo was started and data reported for the placebo condition were collected after the individual was entirely off haloperidol for at least 14 days". Comparator (placebo) for minimum 34 days: matching placebo capsules
Outcomes	Primary outcomes: rate of self‐injurious behaviour, measured with a scale developed by the study authors for self‐injurius behaviour irritability, measured using the ABC‐I subscale (Aman 1985) Secondary outcomes: none reported Timing of outcome assessments: not reported Trial registry: not reported
Notes	Study start date: not reported Study end date: not reported Source of funding: supported, in part, by a grant from the National Institute of Mental Health (MH50358‐8) Conflicts of interest: none declared
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Details not provided
Allocation concealment (selection bias)	Unclear risk	Details not provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"All behaviour analysts, nurses, and inpatient unit staff were blind to the medication assignments. The physician was aware of the medication assignment"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "All behaviour analysts, nurses and inpatient unit staff were blind to the medication assignments". "To keep staff blinded to the different patterns of medication adjustment for behavioural treatment versus medication non‐responders, the letters used to identify the medication could be changed by the physician even if the medication was not changed".
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The data for the 15 participants were recorded in regards to response to behavioural treatment (% change in SIB), max dose haloperidol (mg/day), response to haloperidol (% change in SIB) and response to placebo (% change in SIB). ABC Irritability baseline and endpoint data were not provided for placebo despite being measured weekly. Other participants had placebo condition measured after 14 days off haloperidol; unclear whether there was any ITT analysis for these missing data.
Selective reporting (reporting bias)	High risk	ABC baseline and endpoint data were not provided for placebo at all.
Other bias	Low risk	None identified