Effects of phototherapy in patients with delayed sleep phase syndrome.

Phototherapy was given to six patients with delayed sleep phase syndrome (DSPS). Polysomnography (PSG) and core body temperature were examined before and after phototherapy. Phototherapy was administered to each patient for 5 days, and this treatment not only advanced the delayed sleep phase but also delayed the time of minimum body temperature in all patients. On the PSG, decreases in total sleep time and amounts of stages 2 and REM were observed after phototherapy. These results suggest that phototherapy is effective even in the short term in advancing delays in sleep phase and time of minimum body temperature in DSPS patients.