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.

Method:

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.