Original ArticleSleep Variables as Predictors of Treatment Effectiveness and Side Effects of Stimulant Medication in Newly Diagnosed Children with Attention-Deficit/Hyperactivity DisorderDavidson, Fiona PhD*; Rigney, Gabrielle PhD*,†; Rusak, Benjamin PhD*; Chambers, Christine PhD*; Rajda, Malgorzata MD‡; Corkum, Penny PhD*Author Information *Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada; †School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Australia; ‡Department of Psychiatry, Dalhousie University, Halifax, NS, Canada. Address for reprints: Penny Corkum, PhD, Department of Psychology and Neuroscience, Dalhousie University, 1355 Oxford St, PO Box 15000, Halifax, NS B3H 4R2, Canada; e-mail: [email protected]. Supported by the Canadian Institutes for Health Research CIHR FRN# 111087 and CIHR FRN# 81191. Disclosure: The authors declare no conflict of interest. Journal of Developmental & Behavioral Pediatrics: January 2021 - Volume 42 - Issue 1 - p 1-8 doi: 10.1097/DBP.0000000000000866 Buy Metrics Abstract Objective: There is a growing body of research on the impact of stimulant medication on sleep in children with attention-deficit/hyperactivity disorder (ADHD). Negative sleep side effects are a common reason for nonadherence or for discontinuing a course of treatment. However, there is no published evidence as to whether pretreatment sleep can predict responses to treatment and the emergence of side effects. Method: In this study, baseline sleep variables were used to predict therapeutic effect (i.e., reduction of ADHD symptoms) and side effects (both sleep and global side effects) in a sample of newly diagnosed, medication-naive children (n = 50). Results: The results of hierarchical regression analysis showed that parent-reported shorter sleep duration before medication treatment significantly predicted better response to treatment, independent of pretreatment ADHD symptoms. Baseline sleep features did not significantly predict global (nonsleep) side effects but did predict increased sleep side effects during treatment. Conclusion: These results indicate that baseline sleep variables may be helpful in predicting therapeutic response to medication and sleep disturbance as a side effect of stimulant medication. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.