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Light on Winter Darkness

Alternatives to Bright Light Therapy


Updated September 28, 2011

Dawn Simulation

Imagine receiving treatment while you sleep. A computer chip controls a lamp positioned over your bed that simulates a slow, gradual sunrise in the final hours of sleep, at light levels far lower than those of bright light therapy. You sleep through most of the signal, and wake up spontaneously as the "sun crosses the horizon." In the middle of February, the computer can control the lamp to match a sunrise in the middle of May. It's still dark outside when you wake up, but you're done with treatment for the day. After about a week of simulated dawn exposures, your depression lifts and you sense a heightened alertness as you get out of bed.

Futuristic? Yes. But clinical trials of dawn simulation are underway at Columbia University Medical Center, with initial positive results. A controlled trial at the University of Washington showed that dawns peaking at 250 lux were more effective than "placebo dawns" peaking at 2 lux. Already, one sees dawn simulators on the market, but, as with light boxes, design features vary widely, often without documentation of efficacy.

Why would one choose dawn simulation at this point? It's an option for people who cannot spare 30 minutes for bright light therapy before work, and it may be particularly suited for children with SAD who find it hard to sit still at a light box.

High-Density Negative Air Ionization

This is a recent discovery that was unexpected. In their study of bright light therapy, Dr. Terman's group wanted to show that the treatment was better than a placebo response. They gave negative air ionizers to some of their patients, half of which produced low levels similar to what you'd get from a home air cleaner, and half of which produced very high levels similar to those used by industry (for example, in industrial "clean rooms" and photography darkrooms). We can't perceive the balance of negative and positive ions in the environment. Negative ions are found in higher concentration at the seashore and after spring thunderstorms, and at lower concentration indoors in winter in heated rooms. Thus, the research volunteers were unable to tell which dose of ions they received (while it was always obvious when they received bright light).

Gradually, across three weeks of daily exposure, the group with high-density ions showed an antidepressant response, while the group with low-density ions remained depressed. On the basis of a single experiment, we can't conclude that bright light therapy and negative ion therapy are equally effective. More research needs to be done, and the results have to be replicated. In a recently completed trial, we were able to show that high-density ions are effective even when administered during sleep.

Antidepressant Drugs

Two standard drug trials were completed in 1998, using the popular antidepressants Prozac (fluoxetine) and Zoloft (sertraline) -- for a summary, see the last reference on this page. Both produced significant improvement when measured against placebo pills, but the degree of improvement fell short of that seen in placebo-controlled trials of bright light. Another trial is testing whether Wellbutrin (bupropion) can be used prophylactically, that is, to prevent the onset of winter depression altogether. Take-home messages:

  • Bright light therapy should be the first-line treatment for SAD: the antidepressant response tends to be stronger than for drugs, and there are relatively few side effects. But these drugs are useful when light therapy is impossible to schedule or there is some other reason not to use lights (such as a degenerative retinal disease).
  • If light therapy fails, it makes sense to try one of these drugs.
  • If light therapy gives partial improvement, but symptoms linger, it makes sense to try combining light with one of these drugs, for there may be further improvement.


Avery DH, Bolte MA, Wolfson JK, Kazuras A. "Dawn simulation compared with a dim red signal in the treatment of winter depression." Biological Psychiatry 36 (1994) :181-188.

Eastman CI, Young MA, Fogg LF, Liu L, Meaden PM. "Bright light treatment of winter depression: a placebo-controlled trial." Archives of General Psychiatry 55 (1998) :883-889.

Lamberg L. "Dawn's early light to twilight's last gleaming." Journal of the American Medical Association 280 (1998): 1556-1558.

Terman, M. on sleep. In Schwartz WJ (ed.), Sleep Science: Integrating Basic Research and Clinical Practice. Basel: Karger, 1997: 230-251.

Terman M, Terman JS, Ross DC. "A controlled trial of bright light and negative air ionization for treatment of winter depression." Archives of General Psychiatry 55 (1998): 875-882.

Terman M, Terman JS, Williams JBW. "Seasonal affective disorder and its treatments." Journal of Practical Psychiatry and Behavioral Health 5 (1998): 287-303.

More About SAD

  1. About.com
  2. Health
  3. Depression
  4. Types of Depression
  5. Seasonal Affective Disorder
  6. Antidepressants and Other Alternatives to Light Therapy

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