title: Differential effects of predictors on methylphenidate initiation and discontinuation among young people with newly diagnosed attention-deficit/hyperactivity disorder.
abstract: OBJECTIVE
  Previous population-based studies have identified factors accounting for differential utilization of psychotropic medications among young patients with attention-deficit/hyperactivity disorders (ADHDs); yet, few analyses have addressed changes in such factors that can occur in the help-seeking process. The aim of this study was to examine patient- and service provider-level predictors for methylphenidate (MPH) initiation and discontinuation.
  
  
  METHODS
  This cohort study included 10,153 newly diagnosed ADHD patients under 18 years of age in 2000, identified from the National Health Insurance Research Database. The risk association was estimated by time-dependent survival analyses, as indexed by hazard ratio.
  
  
  RESULTS
  Approximately 30% of young people received MPH treatment within the year of their ADHD diagnosis, and virtually none remained in treatment beyond 12 months. Regardless of co-morbidity status, the following were significantly associated with earlier initiation of MPH treatment: older age (e.g., adjusted hazard ratio [aHR] for age 12-17 = 4.5-7.6), lower socioeconomic status (aHR = 1.2-1.4), southern residence (aHR = 1.4-1.6), receiving the diagnosis while school was in session (aHR = 1.3-1.4), receiving the diagnosis from a physician specializing in pediatrics or psychiatry (aHR = 7.3-16.8), and receiving the diagnosis in a district hospital/clinic (aHR = 1.3-1.7). However, once treatment started, older ages appeared to increase the risk of early discontinuation by 15%, and the corresponding estimates for receiving initial MPH in a regional hospital or district hospital/clinic were 27% and 32%, respectively. Change in treatment location upon subsequent visit was associated with a 58% reduction in early discontinuation.
  
  
  CONCLUSIONS
  This information about time-varying predictors for MPH utilization throughout treatment may provide insight into the delivery of pediatric mental health services and has important implications for the design of clinical treatment programs.
authors.affiliation: Division of Mental Health and Addiction Medicine, Institute of Population Health Sciences, National Health Research Institutes, Miaoli County, Taiwan. chuanychen@ym.edu.tw
authors.forename: Chuan-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Hsueh-Han
authors.initials: HH
authors.lastname: Yeh
authors.forename: Kuang-Hung
authors.initials: KH
authors.lastname: Chen
authors.forename: I-Shou
authors.initials: IS
authors.lastname: Chang
authors.forename: Erin Chia-Hsuan
authors.initials: EC
authors.lastname: Wu
authors.forename: Keh-Ming
authors.initials: KM
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage*; D016016:Proportional Hazards Models; D012959:Socioeconomic Factors; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate