title: Long-term effects of stimulants on neurocognitive performance of Taiwanese children with attention-deficit/hyperactivity disorder.
abstract: BACKGROUND
  Attention-deficit/hyperactivity disorder (ADHD) is a common behavioral and neurocognitive disorder in school-age children. Methylphenidate (MPH) is the most frequently prescribed CNS stimulant for ADHD. The aim of this study is to evaluate the changes in intelligence quotient and domains of neurocognitive function after long-term MPH treatment of Taiwanese children with ADHD.
  
  
  METHODS
  The Wechsler Intelligence Scale (WISC-III) was administrated twice at an interval of at least one year for all 171 subjects (6-12 years) and 47 age- and gender-matched children without ADHD. The ADHD-Rating scale and Clinical Global Impression-Severity (CGI-S) were also used at the time of enrolment, and at 6 months and one year later.
  
  
  RESULTS
  Taiwanese children with ADHD had lower Verbal IQ (VIQ) and Full IQ (FIQ) and performed poorly on several subtests of the WISC-III, including Similarities, Vocabulary, and Coding, compared to healthy children without ADHD. After one year of MPH treatment, significant decrements in all scores of the ADHD-Rating scale and CGI-S and increments in several domains of the WISC-III, including FIQ, VIQ, PIQ, Perceptual Organization Index (POI), Picture Completion, Picture Arrangement, Object Assembly, and Digit Span were observed. When the ADHD children under MPH treatment were subdivided into two age groups (6-8 years and 9-12 years), significantly better performance in some subtests and subscales of the WISC-III (such as Similarities, Comprehension, and Object assembly) was found in the 6-8 years age group.
  
  
  CONCLUSIONS
  Long-term MPH treatment may improve the neurocognitive profiles of the ADHD children, as seen in their performance in several subtests and in the IQ scores on the WISC-III. And this improvement had no correlation with the decrement of ADHD symptoms. Starting stimulant treatment at as young an age as possible is advised due to the greater benefits in the 6-8 years age group, as seen in this study. More research in this area is also needed to confirm these results.
authors.forename: Ching-Shu
authors.initials: CS
authors.lastname: Tsai
authors.affiliation: Department of Child Psychiatry, Chang Gung Memorial Hospital and University, Linkou, Taiwan. hu1109s@yahoo.com.tw.
authors.forename: Yu-Shu
authors.initials: YS
authors.lastname: Huang
authors.forename: Chen-Long
authors.initials: CL
authors.lastname: Wu
authors.forename: Fang-Ming
authors.initials: FM
authors.lastname: Hwang
authors.forename: Kin-Bao
authors.initials: KB
authors.lastname: Young
authors.forename: Ming-Horng
authors.initials: MH
authors.lastname: Tsai
authors.forename: Shih-Ming
authors.initials: SM
authors.lastname: Chu
mesh_terms: D044466:Asian People; D001288:Attention / Q000187:drug effects*; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000523:psychology; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D003071:Cognition / Q000187:drug effects*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000187:drug effects*; D007361:Intelligence Tests; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D013624:Taiwan; D016896:Treatment Outcome
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate