title: Reinforcing and subjective effects of methylphenidate in adults with and without attention deficit hyperactivity disorder (ADHD).
abstract: BACKGROUND
  There has been controversy over the abuse potential of methylphenidate (MPH) in the context of treatment for attention deficit hyperactivity disorder (ADHD).
  
  
  OBJECTIVE
  The objective of this study was to compare the reinforcing and subjective effects of oral MPH in adults with and without ADHD.
  
  
  METHODS
  Following screening, 33 adults (n = 16 with ADHD; n = 17 free from psychiatric diagnoses) completed four pairs of experimental sessions, each of which included a sampling session and a self-administration session. During sampling sessions, subjects received in randomized order 0 (placebo), 20, 40, and 60 mg MPH. During self-administration sessions, subjects completed a progressive ratio (PR) task to earn portions of the dose received on the corresponding sampling session. Subjective effects were recorded throughout all sessions. The main outcome measure for the study was the number of ratios completed on the PR task. Secondary measures included peak subjective effects and area-under-the-curve values for subjective effects.
  
  
  RESULTS
  Compared to the control group, the ADHD group completed more ratios on the PR task. Both groups showed robust effects of methylphenidate on subjective endpoints. Main effects of group were noted on subjective effects involving concentration and arousal.
  
  
  CONCLUSIONS
  Compared to placebo, MPH produced reinforcing effects only for the ADHD group and not for the control group. Increases in stimulant-related subjective effects in non-ADHD subjects were not associated with drug reinforcement.
authors.affiliation: Department of Psychiatry, Duke University Medical Center, Durham, NC 27701, USA. Kolli001@mc.duke.edu
authors.forename: Scott H
authors.initials: SH
authors.lastname: Kollins
authors.forename: Joseph
authors.initials: J
authors.lastname: English
authors.forename: Rachel
authors.initials: R
authors.lastname: Robinson
authors.forename: Matt
authors.initials: M
authors.lastname: Hallyburton
authors.forename: Allan K
authors.initials: AK
authors.lastname: Chrisman
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000523:psychology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000627:therapeutic use*; D002755:Choice Behavior; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage / Q000627:therapeutic use*; D012054:Reinforcement, Psychology; D012646:Self Administration; D019966:Substance-Related Disorders / Q000523:psychology; D011795:Surveys and Questionnaires
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate