Free-running circadian rhythm disorder in the sighted – case report & discussion

Free-running disorder (FRD) is characterized by inability to maintain stable entrainment to a 24h sleep-wake pattern. Patients with FRD show a sleep/wake pattern similar to those observed in time-free environments bereft of zeitgebers.FRD is common in blind patients, and rarely occurs in sighted individuals. In individuals with no visual impairment, males are more commonly affected. Here, two unusual cases of FRD in young, sighted females are presented. Both patients responded to treatment with melatonin, but derived no perceived benefit from phototherapy