Acute Stimulant Treatment and Reinforcement Increase the Speed of Information Accumulation in Children with ADHD
The current studies utilized drift diffusion modeling (DDM) to examine how reinforcement and stimulant medication affect cognitive task performance in children with ADHD. In Study 1, children with (n = 25; 88 % male) and without ADHD (n = 33; 82 % male) completed a 2-choice discrimination task at baseline (100 trials) and again a week later under alternating reinforcement and no-reinforcement contingencies (400 trials total). In Study 2, participants with ADHD (n = 29; 72 % male) completed a double-blind, placebo-controlled trial of 0.3 and 0.6 mg/kg methylphenidate and completed the same task utilized in Study 1 at baseline (100 trials). Children with ADHD accumulated information at a much slower rate than controls, as evidenced by a lower drift rate. Groups were similar in nondecision time and boundary separation. Both reinforcement and stimulant medication markedly improved drift rate in children with ADHD (ds = 0.70 and 0.95 for reinforcement and methylphenidate, respectively); both treatments also reduced boundary separation (ds = 0.70 and 0.39). Reinforcement, which emphasized speeded accuracy, reduced nondecision time (d = 0.37), whereas stimulant medication increased nondecision time (d = 0.38). These studies provide initial evidence that frontline treatments for ADHD primarily impact cognitive performance in youth with ADHD by improving the speed/efficiency of information accumulation. Treatment effects on other DDM parameters may vary between treatments or interact with task parameters (number of trials, task difficulty). DDM, in conjunction with other approaches, may be helpful in clarifying the specific cognitive processes that are disrupted in ADHD, as well as the basic mechanisms that underlie the efficacy of ADHD treatments.
KeywordsADHD Drift rate Diffusion model Reinforcement Methylphenidate
This research was funded by grant R01MH069434 to LWH from the National Institute of Mental Health.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in this study.
- American Psychiatric Association (2000). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: American Psychiatric Association.Google Scholar
- Bubnik, M. G., Hawk Jr., L. W., Pelham Jr., W. E., Waxmonsky, J. G., & Rosch, K. S. (2015). Reinforcement enhances vigilance among children with ADHD: comparisons to typically-developing children and to the effects of methylphenidate. Journal of Abnormal Child Psychology, 43, 149–161.CrossRefPubMedPubMedCentralGoogle Scholar
- DeVito, E. E., Blackwell, A. D., Clark, L., Kent, L., Dezsery, A. M., Turner, D. C., & Sahakian, B. J. (2009). Methylphenidate improves response inhibition but not reflection-impulsivity in children with attention deficit hyperactivity disorder (ADHD). Psychopharmacology, 202, 531–539.CrossRefPubMedGoogle Scholar
- Dovis, S., Van der Oord, S., Wiers, R. W., & Prins, P. J. M. (2013). Can motivation normalize working memory and task persistence in children with attention-deficit/hyperactivity disorder? The effects of money and computer gaming. Journal of Abnormal Child Psychology, 40, 669–681.CrossRefGoogle Scholar
- Epstein, J. N., Brinkman, W. B., Froehlich, T., Langberg, J. M., Narad, M. E., Antonini, T. A., & Altaye, M. (2011). Effects of stimulant medication, incentives, and event rate on reaction time variability in children with ADHD. Neuropsychopharmacology, 36, 1060–1072.CrossRefPubMedPubMedCentralGoogle Scholar
- Fabiano, G. A., Pelham, W. E., Waschbusch, D. A., Gnagy, E. M., Lahey, B. B., Chronis, A. M., et al. (2006). A practical measure of impairment: psychometric properties of the impairment rating scale in samples of children with attention deficit hyperactivity disorder and two school-based samples. Journal of Clinical Child & Adolescent Psychology, 35, 369–385.CrossRefGoogle Scholar
- Fosco, W. D., Hawk, L. W., Jr., Rosch, K. S., & Bubnik, M. G. (2015). Evaluating cognitive and motivational accounts of greater reinforcement effects among children with attention-deficit/hyperactivity disorder. Behavioral and Brain Functions, 11. Retrieved from https://behavioralandbrainfunctions.biomedcentral.com/articles/10.1186/s12993-015-0065-9
- Huang-Pollock, C., Ratcliff, R., McKoon, G., Shapiro, Z., Weigard, A., & Galloway-Long, H. (2016). Using the diffusion model to explain cognitive deficits in attention deficit hyperactivity disorder. Journal of Abnormal Child Psychology, 1–12.Google Scholar
- Karalunas, S. L., Geurts, H. M., Konrad, K., Bender, S., & Nigg, J. (2014). Annual research review: reaction time variability in ADHD and autism spectrum disorders: measurements and mechanisms of a proposed trans-diagnostic phenotype. Journal of Child Psychology and Psychiatry, 55, 685–710.CrossRefPubMedPubMedCentralGoogle Scholar
- Pelham, W. E., Burrows-McLean, L., Gnagy, E. M., Fabiano, G. A., Coles, E. K., Wymbs, B. T., & Waschbusch, D. A. (2014). A dose-ranging study of behavioral and pharmacological treatment in social settings for children with ADHD. Journal of Abnormal Child Psychology, 42, 1019–1031.CrossRefPubMedPubMedCentralGoogle Scholar
- Rosch, K. S., Fosco, W. D., Pelham Jr., W. E., Waxmonsky, J. G., Bubnik, M. G., & Hawk Jr., L. W. (2016). Reinforcement and stimulant medication ameliorate deficient response inhibition in children with attention-deficit/hyperactivity disorder. Journal of Abnormal Child Psychology, 44, 309–321.CrossRefPubMedPubMedCentralGoogle Scholar
- Shaffer, D., Fisher, P., Lucas, C. P., Dulcan, M. K., & Schwab-Stone, M. E. (2000). NIMH diagnostic interview schedule for children version IV (NIMH DISC-IV): description, differences from previous versions, and reliability of some common diagnoses. Journal of the American Academy of Child and Adolescent Psychiatry, 39, 28–38.CrossRefPubMedGoogle Scholar
- Shahar, N., Teodorescu, A. R., Karmon-Presser, A., Anholt, G. E., & Meiran, N. (2016). Memory for action rules and reaction time variability in attention-deficit/hyperactivity disorder. Biological Psychiatry: cognitive Neuroscience and Neuroimaging, 1, 132–140.Google Scholar
- Spencer, S. V., Hawk Jr., L. W., Richards, J. B., Shiels, K., Pelham Jr., W. E., & Waxmonsky, J. G. (2009). Stimulant treatment reduces lapses in attention among children with ADHD: the effects of methylphenidate on intra-individual response time distributions. Journal of Abnormal Child Psychology, 37, 805–816.CrossRefPubMedPubMedCentralGoogle Scholar
- Strand, M. T., Hawk Jr., L. W., Bubnik, M., Shiels, K., Pelham Jr., W. E., & Waxmonsky, J. G. (2012). Improving working memory in children with attention-deficit/hyperactivity disorder: the separate and combined effects of incentives and stimulant medication. Journal of Abnormal Child Psychology, 40, 1193–1207.CrossRefPubMedPubMedCentralGoogle Scholar
- Wechsler, D. L. (2003). Wechsler intelligence scale for children - fourth edition (WISC-IV). San Antonio, TX: The Psychological Corporation.Google Scholar