title: The acute effect of methylphenidate in Brazilian male children and adolescents with ADHD: a randomized clinical trial.
abstract: OBJECTIVE
  To evaluate the acute efficacy of methylphenidate (MPH) in Brazilian male children and adolescents with ADHD.
  
  
  METHODS
  In a 4-day, double-blind, placebo-controlled, randomized, fix dose escalating, parallel-group trial, 36 ADHD children and adolescents were allocated to two groups: MPH (n = 19) and placebo (n = 17). Participants were evaluated pre- and posttreatment using the 10-item Conners Abbreviated Rating Scale (ABRS), the Children's Global Assessment Scale (CGAS), and a simplified version of the Continuous Performance Test (CPT).
  
  
  RESULTS
  The MPH group had a significantly greater decrease in ABRS scores and a significantly higher increase in CGAS scores than the placebo group (p < 0.01). The MPH group showed also a significantly higher proportion of patients with a robust improvement (decrement of at least 50% in the ABRS score after the intervention) than the placebo group (p < 0.01). The MPH effect size for the ABRS was 1.05 (95% CI = 0.73-1.37).
  
  
  CONCLUSIONS
  Our results extend the efficacy of MPH on the ADHD core symptoms extensively demonstrated in clinical trials with samples from some developed countries to a sample from a developing country where a diverse culture may modulate the clinical presentation of the disorder.
authors.affiliation: Federal University of Rio Grande do Sul, Brazil.
authors.forename: C M
authors.initials: CM
authors.lastname: Szobot
authors.forename: C
authors.initials: C
authors.lastname: Ketzer
authors.forename: M A
authors.initials: MA
authors.lastname: Parente
authors.forename: J
authors.initials: J
authors.lastname: Biederman
authors.forename: L A
authors.initials: LA
authors.lastname: Rohde
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000188:drug therapy* / Q000208:ethnology*; D001938:Brazil; D000697:Central Nervous System Stimulants / Q000008:administration & dosage* / Q000627:therapeutic use; D002648:Child; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage* / Q000627:therapeutic use; D011581:Psychological Tests; D012720:Severity of Illness Index
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate