Clinical predictors of stimulant efficacy in adults with ADHD

Background: Attention-deficit/hyperactivity disorder (ADHD) is a disorder marked by inattentiveness and/or hyperactivity and increased impulsivity. A common treatment for ADHD is stimulant medications, with a formulation of methylphenidate or amphetamine. Although stimulant medication is effective in most patients, 40% show no response. There have been attempts to predict stimulant efficacy through neuroimaging and electroencephalograms; however, these methods are expensive and not sustainable in day-to-day clinical practices. Objectives: This study aimed to identify clinical factors that could be used to predict which patients would best respond to stimulants. Design: The reporting of this study conforms to the STROBE statement. This was a naturalistic prospective observational study. Methods: Thirty-six medication-naïve adults with ADHD were prescribed stimulant medication and naturalistically followed for an average of 116 days. Demographics, type of stimulant, and seven clinical rating scales were analyzed to identify response predictors. Truncated Poisson regressions, stepwise logistic regressions, receiver operating characteristic curve analysis, and Bonferroni corrections were performed. Results: Executive function impairment and better quality of life were found to be the best indicators for stimulant response. Higher scores on Adult Self-Report (ASR) Thought Problems, Withdrawn Problems, Internalizing Problems, and Intrusive Thoughts were indicative of lower stimulant efficacy. Poorer working memory and task monitoring also predicted lower stimulant response. Conclusion: These clinical measures could aid clinicians and patients in predicting who would better respond to stimulant medications and reduce the time that patients wait before finding an effective treatment. Executive functioning, quality of life, and ASR profile measurements can be used to best manage ADHD symptomology.