6 h). After finding a suitable maintenance dose, the clock time of administration can then be adjusted if the patient still complains of symptoms of ASPS or DSPS. When shifting

the administration time earlier, advancing it no more than 30 min every 2 weeks should be sufficiently conservative, so that the entrainment point will not be crossed. Delaying a person with symptoms of ASPS need not be done incrementally. However, in either case shifting the clock time should be stopped when sleep symptoms abate. These patients should probably remain on melatonin treatment for the rest of their lives. Some minor shifts in clock time of administration may Inhibitors,research,lifescience,medical be required. If not taken daily, escape from steady-state entrainment at the normal phase will likely occur. However, after the pacemaker drifts through a complete cycle, the melatonin dose should

again capture the pacemaker at the optimal Inhibitors,research,lifescience,medical phase. Although long-term studies of melatonin need to be done, it is likely that doses of 0.5 mg or less (which result in levels within the same order of magnitude as those produced by the pineal) should be safe. To date, no serious, irreversible side effects have been unequivocally linked to melatonin even at doses greater than 0.5 mg. Nevertheless, we recommend that continuous melatonin treatment be monitored by a physician or other responsible caregiver, who is familiar with the most recent scientific and Inhibitors,research,lifescience,medical medical literature. Other circadian phase disorders Research in SAD patients Inhibitors,research,lifescience,medical and blind people has helped us understand how to treat circadian phase disorders and syndromes in the general sighted population. These disorders include ASPS and DSPS, jet lag, and shift work maladaptation. All of these disorders and syndromes are to a greater or lesser extent related to the circadian timing system and can be phase typed, according to whether they are phase see more Delayed or phase advanced (Table I). Table I Phase typing for circadian rhythm disorders. Treatment of these disorders is based on the light and melatonin PRCs.44 To provide a corrective phase advance,

Inhibitors,research,lifescience,medical bright light should be scheduled immediately upon awakening in the morning and melatonin should be taken in the afternoon/evening. To provide a corrective phase delay, bright light should be scheduled in the evening and melatonin should be taken in the morning. Delayed sleep phase syndrome Melatonin and light are both Megestrol Acetate effective in treating DSPS.102,103 The first published report of treating DSPS with light was in 1983.33 This topic is reviewed elsewhere.104 Most people with DSPS are younger and prefer to sleep late in the morning, having difficulty falling asleep until as late as 4.00 am. These individuals can be treated by scheduling their waketimes to occur gradually earlier (perhaps 15 min every other day) until the desired waketime is reached. Going outdoors immediately upon awakening for about 30 min will help advance the circadian rhythm of sleep propensity, as will taking 0.