Psychiatric News May 6, 2005
Volume 40 Number 9
© 2005 American Psychiatric Association
p. 29
Clinical & Research News

Light Therapy Kept in Dark Despite Effectiveness

Mark Moran

A new meta-analysis indicates light therapy is comparable to antidepressant medication for certain conditions, but it remains underutilized.

Light therapy appears to be efficacious for seasonal affective disorder (SAD) and for nonseasonal depression, according to a meta-analysis of randomized controlled trials.

The analysis was reported in the April American Journal of Psychiatry. The lead author was Robert N. Golden, M.D., who led a work group charged by APA's Council on Research and Committee on Research on Psychiatric Treatments to use the principles of evidence-based medicine to examine the efficacy of light therapy.

Golden and colleagues found that many of the studies in the literature on light therapy did not meet selection criteria for the meta-analysis, reflecting methodological problems inherent in the study of light. Prominent among these is the difficulty of defining parameters of active versus placebo conditions.

"There is an unavoidable challenge in setting up a placebo condition that subjects cannot distinguish from active treatment, although this usually applies to pharmacotherapy research as well, whenever active treatments have side effects and placebos do not," Golden told Psychiatric News.

Small sample size also characterized some studies that did not meet criteria, reflecting the lack of industry support for research on light, Golden said.

But those studies that did meet selection criteria for the meta-analysis demonstrated a significant reduction in depression symptom severity following bright light therapy in SAD and in nonseasonal depression. The analysis also showed a significant effect with "dawn simulation" in SAD. (Dawn simulation uses a light that comes on very slowly in the early morning, to imitate a natural sunrise. Standard light therapy typically makes use of a light box that provides persistent bright light.)

"When the `noise' from unreliable studies is removed, the effects of light therapy are comparable to those found in many antidepressant pharmacotherapy trials," Golden and colleagues wrote.

They systematically searched PubMed for articles published between January 1975 and July 2003 on light therapy for mood disorders. Included studies were required to be randomized, controlled trials of patients in the acute phase of treatment and to have a credible placebo-control condition.

For bright light treatment of SAD, minimum treatment dose was defined as four days of at least 3,000 lux-hours (for instance, 1,500 lux for two hours or 3,000 lux for one hour). Placebo comparison groups were required to receive a maximum of 300 lux.

For dawn-simulation studies, active intervention was required to consist of increasing light exposure from 0 lux to 200-300 lux over one hour to 2.5 hours, and the placebo condition had to consist of an increase that was less than 5 lux and/or less than 15 minutes in duration.

Golden and colleagues found that only 23 of 173 studies (13 percent) met the selection criteria. But those 23 studies showed a significant reduction in depression symptom severity associated with bright-light treatment and dawn simulation in SAD.

Significant reduction in symptoms was also demonstrated with bright-light treatment in nonseasonal depression. Bright light as an adjunct to pharmacotherapy was not found effective, according to the report.

Norman Rosenthal, M.D., a psychiatrist who pioneered SAD research and treatment using light therapy, told Psychiatric News that the findings confirm that light is extremely effective in the treatment of patients with mood disorders and should help to push the treatment into the mainstream. He emphasized the finding that effect sizes for light therapy were comparable to those found for antidepressant medication.

He underscored the finding that light therapy was also found effective for nonseasonal depression. "I don't think if you asked 100 psychiatrists that even 5 percent would have endorsed that," he said. "So it's a very interesting finding."

He added that the finding should not be surprising given that light is known to impact fundamental neurotransmitter systems.

Rosenthal is a clinical professor of psychiatry at Georgetown University School of Medicine and author of Winter Blues. (The book was originally published in 1989 under the title Seasons of the Mind; it was republished under the new title in 1993, and a second edition was published by the Guilford Press in 1998. The third edition is due out this fall.)

Rosenthal believes the finding that light was not effective as an adjunct to pharmacotherapy is an artifact of the small number of studies that have been conducted on the subject.

It would be "extraordinary" for an antidepressant that is effective "in its own right not to be effective as an adjunct to something else," he said. "That would be almost unprecedented, and my guess is that this is because the quantity of data is insufficient."

Rosenthal said that research on light therapy today has come to a virtual standstill because of a lack of funding, and thus the therapy has been marginalized. Federal funding that had once been generous has dried up, and since equipment used for light therapy does not hold the promise of yielding huge profits for manufacturers, other sources of funding have not materialized.

"There is no money in light, and nobody has a lot to gain from it economically," he said.

The study, "The Efficacy of Light Therapy in the Treatment of Mood Disorders: A Review and Meta-Analysis of the Evidence," is posted online at <http://ajp.psychiatryonline.org/cgi/content/full/162/4/656?>.

Am J Psychiatry 2005 162 656[Abstract/Free Full Text]

Now that is something interesting and new for depression. Nice find Roerich...

Anthony,

Light therapy is just not discussed among fellow colleagues I know. Bring that word up in a polite conversation and it gets dropped quick. Bottom line there is no money to be made by mental health professionals who prescribe light therapy.

Australians should be proud that Melbourne was the site for the first research that offered definitive proof that bright light increases serotonin levels. And naturally, I might add, not with antidepressants! See reference T10 in bold below.

Roerich

A list of some of the research on light therapy:

Key: T Title
AU Author(s)
SO Society or Journal
AB Abstract

TI Beginning to see the light
AU Wirz-Justice A.
SO Arch Gen Psychiatry. 1998 Oct;55(10):861-2
AB The evidence is in that light is an active neurobiological agent... Light therapy is easy to administer in outpatient settings, lacks major side effects, and, importantly, is cost-effective.

This issue of the Archives (probably the most widely respected journal in the field) was largely given over to light treatment.

T2 Treating chronobiologic sleep and mood disorders with bright light
AU Lewy AJ.
SO Psychiatric Annals. 1987 Oct;17(10):664-9
AB One of the most promising non-pharmacological treatment of psychiatric disorders is bright light. The article discusses how bright light and other factors affect human circadian disorders. It supports the hypothesis that winter depression is the result of delayed circadian rhythms with respect to sleep.

T3 Serotonin in the spotlight (letter)
AU Penev PD, Zee PC, Turek FW.
SO Nature. 1997 Jan 9;385:123
AB “Here we report new data ... which raise the possibility that light can significantly modify the processing of serotonergic signals by the mammalian brain. ... suggests new mechanisms that may underlie the beneficial effects of artificial light therapy in circadian timing and mood disorders ... - changes which could have important implications for the use of light as a 'drug' to alter neurochemical activity in the brain."

T4 Effects of light treatment upon mood and melatonin in patients with SAD
AU Winton F, Corn T, Huson LW, Franey C, et al.
SO University of London Institute of Psychiatry Psychological Medicine. 1989 Aug 19;(3):585-590
AB Comparison of artificial daylight and red light treatments on 10 patients (aged 30-73 years) with SAD showed a superior effect from artificial daylight, suggesting that light treatment for SAD achieves more than a placebo effect.

This was one of the first placebo-controlled trials.

T5 Seasonal Affective Disorder in children and adolescents
AU Rosenthal NE, Carpenter CJ, James SP, Parry BL, Rogers SL, Wehr TA.
SO American Journal of Psychiatry. 1986 Mar;143(3):356-8
AB The authors studied seven children with symptoms of SAD. During the winter months the children regularly experienced irritability, fatigue, school difficulties, sadness, and sleep changes as well as other symptoms of SAD found in adults. An open trial of bright environmental light reversed many of these symptoms and improved mood and social functioning in the winter months.

T6 Fighting the Winter Blues with bright light
AU Terman M, Link M.
SO Psychology Today. 1989 Jan/Feb;18-21
AB The authors review the major studies, symptoms and treatments of SAD. They highlight the convenience and effectiveness of artificial light therapy.

T7 Effects of different light wavelengths in SAD
AU Oren D, Brainard GC, Rosenthal N, et al.
SO Am J Psychiatry. 1991 April;148(4):509-511
AB 14 SAD patients were assigned to red or green light treatment for one week in a crossover design. Despite patients’ similar expectations for the antidepressant effect of red and green lights, green light has an efficacy similar to white light, whereas red light resembles placebo in other studies. This study supports the hypothesis that the response to light therapy is mediated by biological rather than psychological/placebo factors.

This was a placebo-controlled trial, showing that the effect of light therapy is not psychosomatic.

T8 Abnormal behavioural and hormonal responses to m-CPP in SAD
AU Rosenthal NE, et al.
SO Psychiatry Res. 1994 May;52(2):181-197
AB SAD sufferers and non-sufferers were randomly assigned bright light treatment for 3 weeks, then randomly assigned infusions of a placebo or m-CPP (a post-synaptic serotonin (5HT) agonist). SAD sufferers who had not received light treatment exhibited “activation-euphoria�, all other candidates did not show these changes. The hypothesis of deficient serotonergic transmission in SAD, leading to supersensitive postsynaptic serotonin receptors is borne out in the replicated abnormal behavioural responses to m-CPP. Light appears to reverse this abnormality, perhaps by increasing serotonergic transmission.

This was a placebo-controlled test and gives a possible insight into the underlying cause of SAD.

T9 SAD, the NIMH follow-up study (over 9 years)
AU Brown C, Schwartz PJ, Yamada EM, Wehr TA, Rosenthal NE.
SO Am J Psychiatry. 1996 Aug;153(8):1028-1036
AB A 9 year study of 59 patients showed that 44% continued to use lights after 9 years, 19% stopped because they did not need to use them any longer. 70% used lights over 2 or more years. A further 19% stopped because of inconvenience (using the 2500 lux 2 hour treatment time). For each winter more patients used lights than used antidepressant medication.

T10 Effect of sunlight and season on serotonin turnover in the brain
AU Lambert GW, Reid C, Kaye DM, Jennings GL, Esler MD.
SO Lancet. 2002 Dec 7;360(9348):1840-2
AB Alterations in monoaminergic neurotransmission in the brain are thought to underlie seasonal variations in mood, behaviour, and affective disorders… We showed that turnover of serotonin by the brain was lowest in winter (p=0.013). Moreover, the rate of production of serotonin by the brain was directly related to the prevailing duration of bright sunlight (r=0.294, p=0.010), and rose rapidly with increased luminosity. Our findings are further evidence for the notion that changes in release of serotonin by the brain underlie mood seasonality and seasonal affective disorder.

This is the first definitive proof that bright light increases serotonin levels. The study was based in Melbourne, Australia (which is famous for having very changeable weather) and it even showed variations on a day-to-day basis.

T11 Opthalmological profile of 71 SAD patients
AU Gorman CP, et al.
SO SLTBR Abstracts. 1993 June
AB No test of central retinal function showed any abnormality over 5 years of the study.

The good thing about this information Roerich, and thankyou very much for making people aware of it, is that I am a big believer in getting off medications, or avoiding them to begin with, if realistic alternatives that are working, are available. I think people should give these other options a try, even if they are on medications, in hope to get off the things.

Whilst I don't like medications, I am certainly not silly enough to tell someone not to use them during the worst of their PTSD, because they do provide a faster relief from pain and suffering compared to many alternate treatments, or maybe more readily known I should say. But something I will stand my ground with, is that people should know what they are putting into their bodies, and medications are generally not in the best interest of a human body for long durations, sometimes even short.

I thank you very much mate for enlightening us all to this type of treatment to help with depression, and hopefully people might take a bit more active interest in it, ask physcians about it, and force physicians into actually pulling their finger out of their backside, getting to grips with reality that people do not want drugs if natural alternatives, or better alternatives, are available, and obviously this being one of them for depression related illness.

Anthony,

You are most welcome! Below is a link to a recent review article. The introduction states:

"Light therapy can provide a potent alternative or adjunct to antidepressant drug treatment. Recent successes in light treatment of major depression with or without seasonal pattern underscore the need for clinicians to familiarize themselves with the methodology for inpatient and outpatient applications."

http://www.cet.org/documents/pdf/ter...0Spectrums.pdf

Roerich

I had terrible trouble during the winter months, and splashed out on a SAD lamp while still being a little cynical about the effect it might have. I tested fortnights on, fortnights off as a personal trial, and I was very impressed. It doesn't resolve all my issues at that time of year, and the British weather is miserable however you look at it, but it helped boost my energy levels so I could at least function from day to day. When I stop using the lamp, I slump into semi-coma again. It takes hours to force myself out of bed. I was convinced! If only I could move to the Mediterranean...

Purdy,

That is some very positive feedback on this process, thankyou. It is great to have sufferers experience shared about all the different facets and avenues of help and support, so we can narrow down more exceptional treatments, opposed to common, but not necessarily helpful treatments.

Speaking of light therapy, I've been musing on this for a few years now:

I prefer the dark. Period. I don't like bright light; never ever been a great fan of it. I prefer to lurk in the shadows. I feel more comfortable there. Though I realize that light therapy makes sense, I wonder if my avoidance of light has to do with fear of exposure, or is it just a personality quirk?

Since I was diagnosed with PTSD last month, I have been researching like a mo-fo and in light of my history I wonder what actually defines my personality vs what is the manifestation of my PTSD/depression/anxiety.

I got one a couple years back...basically noticed over the years that around February I felt flat and lacked energy. I am convinced it helps lift mood, energy and productivity, even if solely because the room is not bathed in that orangey electric light through the middle of winter.

It is set up on the wall over my PC adjacent to me. It is cheaper to run than normal electric lights and is on over much of the winter months. Not wanting to advertise, but you probably will get a much better deal from Ebay...just check the product specifications (lux output, see above). My only quibble, it's an ugly box. But I would not be without it.