Acute effects of nicotine on attention and response inhibition.
Smoking is highly prevalent among patients with Attention Deficit Hyperactivity Disorder (ADHD). Previous studies using the reversed continuous performance task (R-CPT) have suggested that nicotine reduces inattention. Since especially adults with ADHD have been claimed to suffer from a core deficit in inhibitory control, this study aimed at determining whether nicotine improves response inhibition in addition to attention. Sixteen healthy regular smokers participated in a pre/post treatment design in which transdermal patches containing 7 and 21 mg nicotine per day were administered in a counterbalanced, double-blind manner. In a second study, patches containing 0 mg (placebo) and 21 mg per day were administered to a different group of regular smokers. For replication purposes, the R-CPT and the profile of mood states (POMS) were administered. Furthermore, a different version of the continuous performance task (CPT-AX) and the stop-signal task, traditionally used to measure response inhibition, were presented. The high dose of nicotine was found to relieve self-reported Depression in Study 1 and Fatigue in Study 2. Performance data indicated acute effects of nicotine on attention-related, but not on inhibition-related measures. Especially the comparison with placebo revealed decreases in reaction time and variability of responding. The results imply that patients with ADHD smoke to reduce inattention.