Basic Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Pediatr. Jan 9, 2022; 11(1): 48-60
Published online Jan 9, 2022. doi: 10.5409/wjcp.v11.i1.48
Impact of stimulant medication on behaviour and executive functions in children with attention-deficit/hyperactivity disorder
Tasmia Hai, Hanna A Duffy, Julie Anne Lemay, Jean François Lemay
Tasmia Hai, Hanna A Duffy, Werklund School of Education, University of Calgary, Calgary, AB T2N 1N4, Canada
Julie Anne Lemay, Jean François Lemay, Department of Paediatrics, Alberta Children's Hospital/Cumming School of Medicine, University of Calgary, Calgary, AB T3B 6A8, Canada
Author contributions: Hai T assisted with data collection, analyzed and interpreted the data and wrote the manuscript; Duffy HA assisted with data collection and reviewing of the manuscript; Lemay JA assisted with data collection; Lemay JF is the principal investigator of the study, designed the study and edited the manuscript; all authors approved the final version of the article.
Supported by the Alberta Children's Hospital Foundation, Werklund School of Education, University of Calgary.
Institutional review board statement: Ethics approval for the following research has been renewed by the Conjoint Health Research Ethics Board (CHREB) at the University of Calgary. The CHREB is constituted and operates in compliance with the Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans (TCPS 2); Health Canada Food and Drug Regulations Division 5; Part C; ICH Guidance E6: Good Clinical Practice and the provisions and regulations of the Health Information Act, RSA 2000 c H-5. Ethics ID: REB15-3068_REN4.
Conflict-of-interest statement: The authors declare no competing financial interests. No conflict of interest to report.
Data sharing statement: Dataset available from the corresponding author at jf.lemay@ahs.ca.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Jean François Lemay, MD, FRCPC, Professor, Department of Paediatrics, Alberta Children's Hospital/Cumming School of Medicine, University of Calgary, 28 Oki Drive, NW, Room C4-627, Calgary, AB T3B 6A8, Canada. jf.lemay@ahs.ca
Received: March 24, 2021
Peer-review started: March 24, 2021
First decision: June 17, 2021
Revised: July 8, 2021
Accepted: December 2, 2021
Article in press: December 2, 2021
Published online: January 9, 2022
Processing time: 289 Days and 5.2 Hours
ARTICLE HIGHLIGHTS
Research background

Children with attention-deficit/hyperactivity disorder (ADHD) often exhibit behaviour challenges and deficits in executive function (EF) skills. Typically, psychostimulant medications [e.g., methylphenidate (MPH)] are commonly prescribed for children with ADHD. However, psychostimulants are considered effective in 70% of the cases and often have undesirable side effects, including changes in appetite, weight, and sleep. Furthermore, only a handful of studies have investigated the naturalistic long-term impact of MPH medication on EF and behaviour.

Research motivation

The main topics investigated in the current study were to measure EF and behaviour challenges in children with ADHD using both parent rating scale and neuropsychological assessment measures.

Research objectives

The main objectives of the current study were to evaluate behaviour and EF challenges in children with ADHD who were involved in a MPH treatment trial. The participants were assessed across three-time points using both parent rating scale and neuropsychological assessment measures to understand the short-term and long-term naturalistic impact of stimulant medications.

Research methods

Thirty-seven children with ADHD completed a stimulant medication trial (MPH). Children with ADHD completed neuropsychological assessments assessing working memory (Digit Span Backwards and Spatial Span Backwards) and response inhibition (Continuous Performance Test-2). Parents of children with ADHD completed behaviour rating scales related to executive function [Behaviour Rating Inventory of Executive Function (BRIEF)] and behaviour [Behaviour Assessment System for Children, second edition (BASC-2)]. Participants were evaluated at: (1) Baseline (no medication); and (2) Best-dose (BD; following four-week MPH treatment). Additionally, 18 participants returned for a long-term naturalistic follow up (FU; up to two years following BD).

Research results

The results of the current study found significant effects over time on two subscales of BRIEF and four subscales of BASC-2 measures indicating impact on behaviour and EF according to parents. Neuropsychological assessments showed some improvement, but not on all tasks following the medication trial. These improvements did not sustain at FU, with increases in EF and behaviour challenges and a decline in performance on the CPT-II task being observed.

Research conclusions

Parents of children with ADHD reported improvements in EF and behaviours during the MPH trial but were not sustained at FU. Neuropsychological assessment findings were not consistent with participants showing improvement on some response inhibition tasks but not on the working memory tasks. As a result, it is important to combine screening tools and neuropsychological assessments for monitoring medication responses.

Research perspectives

The current study provided information about the impact of stimulant medication on behaviour and EF in children with ADHD. Results showed improvement in EF skills and behaviour in children with ADHD following medication treatment. These improvements were reported by parents through standardized behaviour rating scales. Neuropsychological tests of response inhibition also showed improved performance following medication treatment. However, these improvements did not sustain when reassessed at the FU time point based on parent behaviour rating scales. It is important for healthcare professionals working with individuals with ADHD to consider medication FU to understand the efficacy of continued medication usage. Furthermore, it is possible that as children enter the adolescent years, they may require supplementary psychosocial support combined with pharmacotherapy to ensure more sustained treatment outcomes. Future research investigating the long-term impact of stimulant medication will be helpful to better understand the efficacy of stimulant medications and replicate findings obtained from the current study.