Research Units 2005.

Study characteristics
Methods	8‐week discontinuation phase of McCracken 2002 study
Participants	Inclusion criteria: participants who showed a positive response to risperidone in the previous 8‐week controlled trial (McCracken 2002) and 4‐month open‐label trial. Positive response defined as being a 25% reduction on the ABC‐I subscale and a rating of much improved or very much improved on the CGI improvement scale. Exclusion criteria: no concomitant treatment with psychotropic medication was allowed during any phase of the study, except anticonvulsant treatment for seizure control if the child had been taking a stable dose for 4 weeks and had been free of seizures for 6 months. Location/setting: the 5 clinical sites included the University of California Los Angeles, Ohio State University, Indiana University, Yale University, and Kennedy Krieger Institute (Johns Hopkins University), USA Sample size: 38 participants Number analysed: 32 (16 from each group) Number of withdrawals/dropouts: 2 not included in the analyses however reasons were not provided Gender: 81% were male in the original McCracken study. Mean age: 8.6 years IQ: 73% of participants had a mild to profound intellectual disabilities Baseline ABC‐I or other BoC: following McCracken study ABC‐I was 11.3 Concomitant medications: participants had to be free of all psychotropic drugs at least 2 weeks prior to randomisation (4 weeks for antipsychotics and fluoxetine). History of previous medications: details not reported
Interventions	Risperidone for 8 weeks: the maintenance risperidone dose was reduced by 25% each week until only placebo in the fourth week Placebo for 8 weeks: equivalent placebo
Outcomes	Primary outcomes: relapse rates, measured in % Secondary outcomes: none reported. Apart from relapse rates, no other outcomes or new data were provided. Timing of outcome assessments: all participants were seen weekly for a total of 8 weeks in the discontinuation phase.
Notes	Study start date: not reported Study end date: not reported Source of funding: "NIMH contracts to principal investigators Dr McCracken (grant N01 MH‐70010), Dr Scahill (N01 MH‐70009), Dr McDougle (N01 MH‐70001) and Dr Aman (N01 MH‐80011); NIH Division of Research Resources General Clinical Research Center grants to Indiana University (M01 RR00750), Johns Hopkins University (M01 RR‐00052), Ohio State University (M01 RR‐00034) and to Yale University (M01 RR‐06022). Funding was also received by Dr Scahill from the Korczak Foundation and study medications were donated by Janssen Pharmaceutica." 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	Unclear risk	Details not provided about outcome assessors or clinicians
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "subjects were randomly assigned again, this time either to continued risperidone at the same dose or to gradual placebo substitution, in a double‐blind fashion"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Details not provided
Selective reporting (reporting bias)	Unclear risk	Only relapse reported
Other bias	Unclear risk	Details not provided