Predicting phase timing in delayed sleep phase disorder: The accuracy of melatonin and self-reported sleep timing

The efficacy of Bright Light Therapy and melatonin ad-ministration for Delayed Sleep Phase Disorder is contingent upon an accurate clinical assessment of circadian phase timing. Although the timing of core body temperature provides the most accurate indication of circadian phase timing, the process is costly, time consuming and not clinically viable. The present study investigates whether more cost-effective and convenient estimates of circadian phase timing, including dim-light melatonin variables and self-reported sleep timing, can be used to predict circadian phase derived from core body temperature.