EVALUATING THE ROLE OF MELATONIN IN THE LONG-TERM TREATMENT OF DELAYED SLEEP PHASE SYNDROME (DSPS)

Delayed sleep phase syndrome (DSPS) involves a mismatch between the us ual daily schedule required by the individual's environment and his or her circadian sleep-wake pattern. Patients suffering from DSPS are tr eated with chronotherapy, light therapy, or melatonin administration. While chronotherapy and light therapy are demanding and difficult trea tments that usually lead to compliance problems, melatonin administrat ion is a relatively simple and easy treatment option. Previous studies carried out on relatively small samples of DSPS patients have shown t hat melatonin has a sleep-promoting and entraining action when taken i n the evening. The present study, which accompanied routine treatment in our sleep clinic, examined the efficiency of melatonin treatment in a relatively large population of DSPS subjects by means of subjective reports. The 61 subjects, 37 males and 24 females, were diagnosed wit h DSPS by means of clinical assessment and actigraphy at our sleep cli nic. Their mean pretreatment falling asleep and waking times were 03:0 9 (SD = 86.22 minutes) and 11:31 (SD = 98.58 minutes), respectively. T hey were treated with a 6-week course of 5 mg of oral melatonin taken daily at 22:00. A survey questionnaire was sent to the home of each su bject 12-18 months after the end of the treatment; the survey investig ated the efficiency of the melatonin treatment and its possible side e ffects. Of the patients, 96.7% reported that the melatonin treatment w as helpful, with almost no side effects. Of these, 91.5% reported a re lapse to their pre-treatment sleeping patterns within 1 year of the en d of treatment. Only 28.8% reported that the relapse occurred within 1 week. The pretreatment falling asleep and waking times of patients in whom the changes were retained for a relatively long period of time w ere significantly earlier than those of patients whose relapse was imm ediate (t = 2.18, p<.05; t = 2.39, p<.05, respectively), with no diffe rence in sleep duration. The implications of these findings, as well a s further research possibilities, are discussed.