Variability of response time as a predictor of methylphenidate treatment response in korean children with attention deficit hyperactivity disorder.
OBJECTIVE
Methylphenidate (MPH) is an effective medication for the treatment of attention deficit hyperactivity disorder (ADHD). However, about 30% of patients do not respond to or are unable to tolerate MPH. Based on previous findings, we hypothesized that great variability in response time (RT) among Korean children with ADHD on a computerized continuous performance attention test would be related to poor MPH treatment response.


METHODS
Children (ages 6-18 years) with ADHD were recruited for a prospective 12-week, open-labeled, multicenter study to examine optimal dosage of OROS methylphenidate. Of the 144 subjects selected, 28 dropped out due to adverse events, medication noncompliance, or follow-up loss, and an additional 26 subjects with comorbid disorders were excluded from statistical analyses. We defined 'responders' as subjects who received a score of less than 18 on the attention deficit hyperactivity disorder rating scale (ARS; Korean version, K-ARS) and a score of 1 or 2 on the Clinical Global Impression-Improvement scale (CGI-I). RT variability was assessed with the ADHD diagnostic system (ADS).


RESULTS
Fifty-nine (67%) subjects responded to MPH treatment. The non-responders showed greater RT variability at baseline (Mann Whitney U = 577.0, p < 0.01). Baseline RT variability was a significant predictor of MPH response (Nagelkerke R(2) = 0.136, p < 0.01). It predicted 94.9% of responder, 17.2% of non-responder and 69.3% of overall group.


CONCLUSIONS
High RT variability may predict poor response to MPH treatment in children with ADHD.
Lee
Seung-Hye
SH
Department of Psychiatry, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, Seoul, Korea.
Song
Dong-Ho
DH
Kim
Bung-Nyun
BN
Joung
Yoo Sook
YS
Ha
Eun Hye
EH
Cheon
Keun-Ah
KA
Shin
Yee-Jin
YJ
Yoo
Hee Jeong
HJ
Shin
Dong-Won
DW
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D002648:Child; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D008774:Methylphenidate / Q000627:therapeutic use*; D011930:Reaction Time; D016896:Treatment Outcome
D008774:Methylphenidate