Carey 2002.

Study characteristics
Methods	48‐week cross‐over trial of secretin versus placebo
Participants	Inclusion criteria: aged 2‐8 years met DSM‐4 criteria for diagnosis of autism or PDD had not had a recent case of acute pancreatitis had not previously received an infusion of secretin Exclusion criteria: not reported Location/setting: Developmental and Behavioral Pediatrics Division at the Medical College of Ohio, USA Sample size: 8 in total Number of withdrawals/dropouts: not reported Gender: 8 boys Mean age: 5 years IQ: "general developmental level based on parent report on the Child Development Inventory ranged from 16 to 39 months". Baseline ABC‐I or other BoC: ABC‐I secretin 24.5, placebo 15.5 Concurrent drug use: details not provided History of previous medications: details not provided
Interventions	Intervention (single dose of secretin): single dose of 2 IU of secretin/kg of body weight Comparator (single dose of placebo): equivalent single dose of placebo
Outcomes	Primary outcomes: irritability, measured using the ABC‐I subscale (Aman 1985); AEs Secondary outcomes: none reported Timing of outcome assessment: ABC‐I: prior to infusion and then weekly for 8 weeks
Notes	Study start date: not reported Study end date: not reported Funding source: not reported Conflicts of interest: none declared
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	All participants were randomised into 2 groups.
Allocation concealment (selection bias)	Unclear risk	Details not provided
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐blinded, however no further details provided
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Details not provided
Incomplete outcome data (attrition bias) All outcomes	High risk	Complete parent and teacher data were obtained for 8 of the total 21 project participants.
Selective reporting (reporting bias)	Unclear risk	Protocol was not provided so unclear if all outcomes were reported
Other bias	High risk	Participants were recruited from a list of children whose parents contacted the Developmental and Behavioral Pediatrics Division at the Medical College of Ohio to request a trial of secretin for their child.