Dawn simulation
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Dawn simulation is a technique used in the treatment of Seasonal Affective Disorder, also known as winter depression. It was developed 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. Clinically, it has been used successfully in two ways: with a naturalistic dawn mimicking a springtime sunrise (but used in mid-winter when it is still dark outside), or a "sigmoidal"-shaped dawn (usually 30 minutes to 2 hours). 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. 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. Some studies have shown dawn simulation to be more effective than standard bright light therapy while others have shown no difference or shown that bright light therapy is superior.[1] [2] The theory behind dawn simulation is based on the fact that early morning light signals are much more effective at advancing the biological clock than are light signals given at other times of day. Dawn simulation also may be more convenient than post-awakening bright light therapy because it is done while the patient is sleeping. Some patients with SAD use both dawn simulation and bright light therapy to provide maximum energy at the start of the day. The technique has also been used clinically with patients who suffer from Delayed Sleep Phase Syndrome, helping them to awaken earlier in gradual steps, as the simulated dawn is moved earlier.
[edit] References
1. ^ Terman M et al. (1989) Dawn and dusk simulation as a therapeutic intervention. Biol Psychiatry. 25:966-970.
2. ^ Avery DH et al. (2001) Dawn simulation and bright light in the treatment of SAD: a controlled study. Biol Psychiatry. 50:205–16.
3. ^ Terman M, Terman JS (2006) Controlled trial of naturalistic dawn simulation and negative air ionization for seasonal affective disorder. Amer J Psychiatry. 163:2126-2133.
