Furthermore, nicotine itself can increase cognitive performance in ADHD patients (Newhouse et al., 2004; Levin et al., 2006) and since recently, clinical trials are being performed to test the efficacy of nAChR subtype specific agonists to increase cognitive performance in ADHD patients (Bain et al., 2013; Jucaite et al., 2014). The gene discussed is CHRNA4; the disease is attention deficit-hyperactivity disorder.