C. Richard Clark, Leanne M. Williams, Nicholas J. Cooper, David Debrota, Evian Gordon, Daniel F. Hermens, Hannah A.D. Keage, Keage, Hannah, Cooper, Nicholas, Hermens, D, Williams, Leanne, DEBROTA, D, Clark, Christopher, and Gordon, Evian
The effects of methylphenidate (MPH) on 32 healthy human male volunteers (aged 18 to 25 years, mean age = 22.26) were examined using a within-subject design. Each participant attended six testing periods, held once per week. Within each testing period, three repeat testing sessions were undertaken: pre-medication, on-medication and two hours post-medication. In these sessions, dose was manipulated (placebo, 5 mg, 15 mg or 45 mg) according a double-blind placebo design. In this report, we focus on behavioral, autonomic arousal (heart rate, skin conductance) and psychophysiological (ERP) data acquired during the working memory task. We found increased autonomic arousal (heart rate, skin conductance and blood pressure) with MPH. A linear reduction in reaction time, omission errors and target P3 latency, and a corresponding increase in background P3 amplitude was observed with increased MPH dose. The relationship between these measures supported an increase in performance and underlying brain function with MPH. To our knowledge, this is the first paper to use behavioral, arousal and electrophysiological measures in an integrative approach to study the effects of MPH on healthy adults.