Dawn simulation

Clinical trials were conducted by David Avery, MD,[3] in the 1980s at Columbia University following a long line of basic laboratory research that showed animals' circadian rhythms to be exquisitely sensitive to the dim, gradually rising dawn signal at the end of the night.

When used successfully, patients are able to sleep through the dawn and wake up easily at the simulated sunrise, after which the day's treatment is over.

Because the entire treatment is complete before awakening, dawn simulation may be a more convenient alternative to post-awakening bright light therapy.

[5][6] Some patients with seasonal affective disorder use both dawn simulation and bright light therapy to provide maximum effect at the start of the day.

[citation needed] In an elaboration of the method, patients have also been presented with a dim dusk signal at bedtime, with indications that it eases sleep onset.