Research ReportMethylphenidate normalizes emotional processing in adult patients with attention-deficit/hyperactivity disorder: Preliminary findings

Emotional-motivational dysfunctions may significantly contribute to symptoms of attention-deficit/hyperactivity disorder (ADHD). Hyperactive-impulsive symptoms and sensation seeking could be the result of a search for reinforcers, and cognitive dysfunctions might be due to a low motivational drive. Emotional-motivational dysfunctions could also explain social dysfunctions in ADHD patients because they may lead to misinterpretations of emotional and social clues. Since methylphenidate (MPH) is the first choice as a pharmacological treatment in ADHD, we examined its influence on dysfunctional emotional processes. 13 adult ADHD patients were examined twice, without and after intake of MPH according to their personal medication regimen. The affect-modulated startle paradigm was used to assess physiological (affect-modulated startle response) and subjective (valence and arousal ratings) responses to pleasant, neutral and unpleasant visual stimuli. Healthy controls displayed affective startle modulation as expected, with startle attenuation and potentiation while watching pleasant and unpleasant pictures, respectively. In contrast, unmedicated ADHD patients displayed deficient responses to pleasant stimuli; no startle attenuation during the exposure to pleasant pictures was observed. However, MPH reinstated a normal affective startle modulation, as indicated by attenuation and potentiation associated with pleasant and unpleasant pictures, respectively. Valence and arousal ratings of patients were not affected by MPH. The data suggest that MPH as first choice treatment in ADHD has a positive impact on emotional processes in adult ADHD patients and points to the clinical relevance of emotional-dysfunctions in ADHD.

Research Highlights► ADHD patients show a diminished reactivity towards pleasant stimuli. ► Methylphenidate normalizes emotional processing in ADHD patients. ► Results point to the clinical relevance of emotional dysfunctions in ADHD. ► Results point to the mechanism of action of methylphenidate in ADHD.