Methylphenidate Beneficial in ADHD After 2 or More Years

Methylphenidate was effective in the long-term treatment of attention-deficit/hyperactivity disorder (ADHD), according to study data published in the American Journal of Psychiatry.

Investigators performed a placebo-controlled discontinuation study of 94 children and adolescents (age 8 to 18 years) who had been treated with methylphenidate for 2 or more years. Participants were randomly assigned to double-blind continuation of treatment for 7 weeks (36 or 54 mg/day) or gradual withdrawal over 3 weeks followed by 4 weeks of placebo. As primary outcome measures, investigators administered the Attention-Deficit/Hyperactivity Disorder Rating Scale (ADHD-RS) to participants at baseline and after 7 weeks. Secondary outcomes included improvements on the investigator-rated Clinical Global Impressions scale (CGI-I) and the Conners’ Teaching Rating Scale-Revised: Short Form (CTRS-R:S).

The mean (standard deviation [SD]) ADHD-RS scores at baseline for the continuation and discontinuation groups were 21.4 (9.7) and 19.6 (8.9), respectively; after 7 weeks, these increased to 21.9 (10.8) and 24.7 (11.4), respectively. A significant between-group difference was observed in ADHD-RS change over time (−4.6; 95%CI, −8.7 to −0.56), in favor of the continuation group.  The ADHD-RS inattention subscale score also differed significantly between groups, deteriorating much more rapidly in the discontinuation group than in the group receiving continued methylphenidate (P <.05). In addition, the Conners’ Teaching Rating Scale-Revised ADHD index and hyperactivity score worsened more significantly from baseline to 7 weeks in the discontinuation group compared with the continuation group (both P <.05). The Clinical Global Impressions scale indicated worsening of symptoms in 40.4% of discontinuing patients, compared with 15.9% of continuing patients (P =.01). Although none of the participants reported serious adverse events, 13.5% of the participants in the discontinuation group reported at least 1 adverse event compared with 10.6% of the continuation group (P =.46).

The study was limited by its sample size and reliance on the common clinical practice of treating children with methylphenidate without an ADHD diagnosis based on standardized assessments.

Continued treatment with methylphenidate remained effective for youth in this study, although further research with a larger cohort is necessary to confirm these findings. These data also support existing recommendations that patients receive periodic assessment to determine if there is a continued need for methylphenidate treatment.

Reference

Matthijssen AM, Dietrich A, Bierens M, et al. Continued benefits of methylphenidate in ADHD after 2 years in clinical practice: a randomized placebo-controlled discontinuation study [published online May 21, 2019]. Am J Psychiatry. doi:10.1176/appi.ajp.2019.18111296