Modafinil (diphenylmethyl-sulfony-2-acet-amide), an FDA-approved drug for the treatment of narcolepsy and other conditions (Ballon and Feifel, 2006), significantly enhances wakefulness in humans and animals through the activation of DA-dependent pathways and hypocretin neurons (Scammell et al., 2000; Wisor et al., 2001; Korotkova et al., 2007). The gene discussed is HCRT; the disease is narcolepsy.