title: Comorbidity moderates response to methylphenidate in the Preschoolers with Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS).
abstract: OBJECTIVE
  The aim of this study was to examine whether demographic or pretreatment clinical and social characteristics influenced the response to methylphenidate (MPH) in the Preschoolers with ADHD Treatment Study (PATS).
  
  
  METHODS
  Exploratory moderator analyses were conducted on the efficacy data from the PATS 5-week, double-blind, placebo-controlled six-site titration trial. Children (N = 165, age 3-5.5 years) were randomized to 1 week each of four MPH doses (1.25, 2.5, 5, and 7.5 mg) and placebo administered three times per day (t.i.d.). We assessed the fixed effects on the average slope in the regression outcome on moderators, weight-adjusted dose, and the moderator-by-dose interaction using SAS PROC GENMOD.
  
  
  RESULTS
  A significant interaction effect was found for a number of co-morbid disorders diagnosed in the preschoolers at baseline (p = 0.005). Preschoolers with three or more co-morbid disorders did not respond to MPH (Cohen's d at 7.5 mg dose relative to placebo = -0.37) compared to a significant response in the preschoolers with 0, 1, or 2 co-morbid disorders (Cohen's d = 0.89, 1.00, and 0.56, respectively). Preschoolers with more co-morbidity were found to have more family adversity. No significant interaction effect was found with the other variables.
  
  
  CONCLUSIONS
  In preschoolers with ADHD, the presence of no or one co-morbid disorder (primarily oppositional defiant disorder) predicted a large treatment response at the same level as has been found in school-aged children, and two co-morbid disorders predicted moderate treatment response; whereas the presence of three or more co-morbid disorders predicted no treatment response to MPH.
authors.affiliation: University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA. jkghuman@email.arizona.edu
authors.forename: Jaswinder K
authors.initials: JK
authors.lastname: Ghuman
authors.forename: Mark A
authors.initials: MA
authors.lastname: Riddle
authors.forename: Benedetto
authors.initials: B
authors.lastname: Vitiello
authors.forename: Laurence L
authors.initials: LL
authors.lastname: Greenhill
authors.forename: Shirley Z
authors.initials: SZ
authors.lastname: Chuang
authors.forename: Sharon B
authors.initials: SB
authors.lastname: Wigal
authors.forename: Scott H
authors.initials: SH
authors.lastname: Kollins
authors.forename: Howard B
authors.initials: HB
authors.lastname: Abikoff
authors.forename: James T
authors.initials: JT
authors.lastname: McCracken
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kastelic
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Scharko
authors.forename: James J
authors.initials: JJ
authors.lastname: McGough
authors.forename: Desiree W
authors.initials: DW
authors.lastname: Murray
authors.forename: Lori
authors.initials: L
authors.lastname: Evans
authors.forename: James M
authors.initials: JM
authors.lastname: Swanson
authors.forename: Tim
authors.initials: T
authors.lastname: Wigal
authors.forename: Kelly
authors.initials: K
authors.lastname: Posner
authors.forename: Charles
authors.initials: C
authors.lastname: Cunningham
authors.forename: Mark
authors.initials: M
authors.lastname: Davies
authors.forename: Anne M
authors.initials: AM
authors.lastname: Skrobala
mesh_terms: D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications* / Q000188:drug therapy* / Q000523:psychology; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000150:complications / Q000523:psychology; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002653:Child Behavior Disorders / Q000150:complications* / Q000523:psychology; D002675:Child, Preschool; D004311:Double-Blind Method; D004493:Education; D004651:Employment / Q000523:psychology; D005006:Ethnicity; D005190:Family; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012727:Sex Characteristics; D020954:Single-Parent Family; D012959:Socioeconomic Factors; D016896:Treatment Outcome
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate