title: Assessment of the integrity of study blindness in a pediatric clinical trial of risperidone.
abstract: OBJECTIVE
  Controlled clinical trials in pediatric psychopharmacology rely on blinded parents and clinical evaluators for outcome data, but little is known about the success of the masking procedures. The blindness of clinical evaluators and parents was examined in a clinical trial of risperidone in autism.
  
  
  METHODS
  Clinical evaluators and parents were asked to guess individual treatment assignments at the end of an 8-week placebo-controlled trial of risperidone in children (aged 5-17 years) with autism. Clinical evaluators did not have access to adverse event data.
  
  
  RESULTS
  The rates of correctly guessing individual treatment assignment (risperidone or placebo) were significantly greater than chance for both clinical evaluators and parents (P < 0.001). Clinical evaluators associated improvement with attribution to risperidone, and lack of improvement with attribution to placebo, in both the risperidone and placebo treatment arms. Parents associated improvement with attribution to risperidone only in the placebo treatment arm. Parents reported that adverse events influenced their guesses, but presence of adverse events was not associated with correctness of guess.
  
  
  CONCLUSIONS
  Improvement was associated with attribution to active treatment regardless of actual treatment assignment, and adverse events did not appear to be a threat to study blindness.
authors.affiliation: Division of Services and Intervention Research, National Institute of Mental Health, Bethesda, MD 20892-9633, USA. bvitiell@mail.nih.gov
authors.forename: Benedetto
authors.initials: B
authors.lastname: Vitiello
authors.forename: Mark
authors.initials: M
authors.lastname: Davies
authors.forename: L Eugene
authors.initials: LE
authors.lastname: Arnold
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: McDougle
authors.forename: Michael
authors.initials: M
authors.lastname: Aman
authors.forename: James T
authors.initials: JT
authors.lastname: McCracken
authors.forename: Lawrence
authors.initials: L
authors.lastname: Scahill
authors.forename: Elaine
authors.initials: E
authors.lastname: Tierney
authors.forename: David J
authors.initials: DJ
authors.lastname: Posey
authors.forename: Naomi B
authors.initials: NB
authors.lastname: Swiezy
authors.forename: Kathleen
authors.initials: K
authors.lastname: Koenig
mesh_terms: D000293:Adolescent; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001321:Autistic Disorder / Q000188:drug therapy*; D002648:Child; D002675:Child, Preschool; D004311:Double-Blind Method; D006801:Humans; D010290:Parents / Q000523:psychology*; D015203:Reproducibility of Results; D012108:Research Personnel / Q000523:psychology*; D018967:Risperidone / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D014150:Antipsychotic Agents; D018967:Risperidone