Please help: What's the best anti SAD light?

Dag Stenberg dag.stenberg at
Fri Jan 17 04:34:16 EST 2003

In bionet.neuroscience Gene Douglas <genedoug at> wrote:
> I know nothing about SAD lights (other than that in many cases, they're
> supposed to help), so I'm wondering: Among brands/models available over the
> night, does anyone have recommendations?

400 lx 2 hours per day seems enough, say
Lam RW, Buchanan A, Mador JA, Corral MR, Remick RA.
J Affect Disord 1992 Apr;24(4):237-43 

As to spectra, maybe reading the articles from which the below are abstracts would

 J Affect Disord 1990 Dec;20(4):209-16 Related Articles, Links
    Effects of different wavelengths in seasonal affective disorder.
    Brainard GC, Sherry D, Skwerer RG, Waxler M, Kelly K, Rosenthal NE.
    Clinical Psychobiology Branch, National Institute of Mental Health,
Bethesda, MD 20892.

    The aim of this study was to compare the relative therapeutic
efficacies of three different light sources for treating winter
depression. A balanced incomplete block crossover design was employed,
whereby all patients (n = 18) were randomly assigned to two out of the
three treatment conditions: white, red and blue light. The degree of
depression was assessed by the 21-item Hamilton Depression Rating Scale.
The data suggest that at a photon density of 2.3 X 10(15) photons/s/cm2,
white light has greater therapeutic benefit than red or blue light. It
is clear that a larger sample population should be tested to confirm
this result. This preliminary finding indicates that light sources
currently in use for phototherapy could not be improved by narrowing the
wavelengths provided and shifting them towards either end of the visible

Psychol Med 2001 Aug;31(6):949-64
    Full-spectrum fluorescent lighting: a review of its effects on
physiology and health.
    McColl SL, Veitch JA.
    Department of Psychology, McGill University, Montreal, Canada.

BACKGROUND: Full-spectrum fluorescent lighting (FSFL) has been credited
with causing dramatic beneficial effects on a wide variety of
behaviours, mental health outcomes and physical health effects, as
compared to other fluorescent lamp types. These effects are hypothesized
to occur because of similarity between FSFL emissions and daylight,
which is said to have evolutionary superiority over other light sources.
METHOD: This review, covering the period 1941-1999, critically considers
the evidence for direct effects of FSFL through skin absorption as well
as indirect effects on hormonal and neural processes. CONCLUSIONS:
Overall, the evidence does not show dramatic effects of fluorescent lamp
type on behaviour or health, neither does it support the evolutionary hypothesis.

Psychiatry Res 1992 Aug;43(2):167-75
    Phototherapy with broad spectrum white fluorescent light: a
comparative study.
    Bielski RJ, Mayor J, Rice J.
    Dept. of Physiology, Michigan State University, East Lansing 48824.

The principles of photobiology suggest that the antidepressant effect of
phototherapy depends on the dose and spectrum of light. We investigated
the effect of spectrum by comparing two broad spectrum fluorescent light
sources with different spectral distributions. In a crossover design, 11
patients with seasonal affective disorder (SAD) were treated with broad
spectrum fluorescent and cool white light for 7 days. Scores on the
Hamilton Rating Scale for Depression were reduced from 22.5 to 8.1 with
broad spectrum fluorescent light and from 23.5 to 8.8 with cool white
light. The results suggest that both light sources are effective treatments.

- Observe that green light is most effective in influencing
night-time melatonin secretion, but melatonin has nothing to do with the
bright light treatment of SAD, see for example:

Psychiatry Res 1995 Apr 28;56(3):221-8 
    Effect of light therapy on salivary melatonin in seasonal affective
    Rice J, Mayor J, Tucker HA, Bielski RJ.
    Department of Psychiatry, Michigan State University, East Lansing
48824-1316, USA.

To investigate the role of a light-induced advance in the timing of the
melatonin rhythm in seasonal affective disorder, 11 depressed patients
underwent 2 weeks of light therapy with full spectrum or cool white
light. Evening saliva samples were collected before and after each week
of treatment and assayed for melatonin to determine the time of onset of
nocturnal secretion. Both treatments reduced depression scores, advanced
the timing of the melatonin rhythm, and increased melatonin
concentrations. Time of onset of the nocturnal increase in melatonin did
not differ between clinical responders and nonresponders, suggesting
that a phase advance in the onset of nocturnal melatonin secretion is
not sufficient to induce clinical remission in seasonal affective disorder. 

-- Dag Stenberg

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