Is Light Therapy Universally Beneficial?

Light therapy has become a widely accepted form of treatment for a variety of physical and psychological issues. The positive effects of sunlight have long been known, but constant exposure to sunlight can have serious negative consequences, including skin damage, skin cancer, and dehydration.

Light therapy (LT) was devised as a way to provide the benefits of light without the repercussions. Clinically, it has been shown to be very effective at improving moods in those with seasonal affective depression issues. These conditions are more prevalent in cold climates with shorter periods of daylight. Light therapy has also been used in the treatment of other mood problems including depression, bipolar, and postpartum depression, and has improved sleep patterns in those with sleep disturbances. Although research has found that LT does not pose significant hazards to those with psychological or physical problems, it is unknown how shorter duration LT affects nonclinical individuals.

To determine if LT has any negative side effects for clinical versus nonclinical individuals, Yevgeny Botanov of the Department of Psychology at the University of Kansas recently conducted a study comparing how a 30-minute exposure session of bright light affected individuals compared to a 30-minute exposure to dim light. Botanov looked at prior exposure and various side effects such as nausea, eye strain, headache and blurred vision.

The results revealed that for both clinical and nonclinical participants, side effects were minimal. The only minimally significant side effects Botanov discovered were blurred vision and eye strain. For clinical versus nonclinical participants, levels of eye strain incidence were 22% and 23% respectively for those exposed to bright light. Further, bright light exposure was found to cause blurred vision in clinical and nonclinical participants at prevalence rates of 12% and 13% respectively.

Although these findings suggest minimal side effects, it is unclear whether any of these were the result of other conditions or prior exposure, particularly among the clinical group. Despite this, Botanov added, “Taken together, the present study results suggest that LT may be particularly well tolerated by nonclinical populations.”

Botanov, Y., Ilardi, S.S. (2013). The acute side effects of bright light therapy: A placebo-controlled investigation. PLoS ONE 8(9): e75893. doi:10.1371/journal.pone.0075893

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  • jane f

    jane f

    October 17th, 2013 at 5:53 AM

    If the benefits outweigh the side effects then count me in. I have always suffered so much when the days start to get shorter and there seems to be more darkness during the winter months. I have read some about light therapy and have thought about it but… I guess it’s just one of those things that kind of seems like a fluke. But the longer it’s been around and the more positives I have started to hear about it I think that I could be a believer. If this could work and bring a little more happiness to me during the long New England winter months then I am willing to give it a try.

  • Sayhealth


    October 24th, 2013 at 5:31 AM

    Actually, there is a very small percentage of the population (myself included) who have what’s often called “reverse SAD.” We have low mood in the winter, and it’s been shown that light treatment can exacerbate negative mood symptoms for those with reverse SAD.

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