The shorter cloudier days of fall and winter bring a loss of energy and other symptoms of depression for over 10 million Americans. Research has shown that light therapy (also known as using a Happy Light) is an effective treatment for this physical and mental seasonal dip known as Seasonal Affective Disorder (SAD) or Winter Depression, general depression, and other sleep and mental health issues.

What's in This Post

For examples of light therapy lamps, check out my blog post: Best Light Therapy Happy Lamps Reviews 

Notes: This article is a summary of my research. It is NOT intended to replace consultation with your personal doctor or other medical professionals. Check in with your own doctor to find out if light therapy is a match for you. 

What is SAD?

SAD stands for Seasonal Affective Disorder.

It is a type of depression that most often strikes when the days shorten and become cloudier in the fall and disappears as the days lengthen and brighten in the spring/summer.

Some people don’t experience full-blown SAD, but instead get a lighter version in which their physical and mental energy is lower than normal for them. This is sometimes called Winter Blues.

Seasonal Affective Disorder, SAD, Treatment

The main treatments for SAD are:

1. Light therapy (AKA Phototherapy, Happy Light)
2. Psychotherapy
3. Exercise
4. Antidepressant medications and supplements

Light therapy is the go-to for SAD treatment.

Dr. Norman Rosenthal, who introduced the idea of using light therapy in the 1980s, and is the author of, Winter Blues: Everything You Need to Know to Beat Seasonal Affective Disorder, says that “ 60 to 80% of SAD sufferers benefit from light therapy.” (1) 

What is Light Therapy or Phototherapy?

Light Therapy is also called Phototherapy or Bright Light Therapy. 

People using light therapy sit by a special bright light therapy lamp that mimics non-UV sunlight for about a half-hour per day with their eyes open. The artificial sunlight taken in through their eyes perks them up by tricking their body into thinking that they are being exposed to daylight.

I’ll talk more about the specifics of the lamps in a minute.

Phototherapy for Depression and Other Mental Health Issues

Recent research on light therapy is showing impressive results for other forms of depression beyond the seasonal form.

Besides SAD, there is also some very encouraging evidence that light therapy may help with (2):

• non-seasonal depression,
• sleep disorders,
• adult attention-deficit/hyperactivity disorder,
• dementia,
• jet lag, and
• adjusting to shift work.

Light therapy has also been shown to help with bipolar depression, but it should only be undertaken with the help of your doctor if you have bipolar disorder since it can stimulate manic symptoms in this group. (3)

Light Therapy for Insomnia

I recently attended a continuing education class, Sleep and Mental Health: Non-Medication Interventions to Restore Sleep Quality and Improve Clinical Outcomes by sleep specialist Dr. Catherine Darley, ND.

Dr. Darley mentioned light therapy for sleep disturbances including insomnia many times throughout the 6-hour training. 

A major problem for many people with insomnia is having a body clock that gets in the way of normal sleep patterns. This question from the class exam summarizes really well why light therapy is a potentially potent intervention for insomnia.

"What lifestyle factor is most important in setting our body clock?

Light Therapy Research

There has been a great deal of research that confirms phototherapy’s benefits for SAD and limited research that demonstrates its effectiveness as treatment for other mental health issues including depression that is not seasonal in nature.

• Dr. Norman Rosenthal first described SAD and the use of light therapy to treat it in the Archives of General Psychiatry journal in 1984. (4) 

• A 1987 study determined that “the antidepressant effects of phototherapy were much greater when light was applied to the eyes than when it was applied to the skin.” (5)

• People with either seasonal or non-seasonal depression showed 12-35% improvement in symptoms within a week of using light therapy in a 1997 study. (6)

• Research repeatedly finds that morning is the best time for the light exposure. (7)

• A review of 10 studies found that light therapy improved the effectiveness of anti-depressant medication in people with non-seasonal or bipolar depression. (8)

• Light therapy outperformed anti-depressant medication in a randomized study of 122 patients with Major Depressive Disorder. (9)

• Harvard scholars who reviewed accumulated research in an article entitled, “The Psychiatry of Light” lamented that phototherapy isn’t used more often as a mental health intervention: “Bright light therapy and the broader realm of chronotherapy remain underappreciated and underutilized, despite their empirical support. Efficacy extends beyond seasonal affective disorder and includes non-seasonal depression and sleep disorders, with emerging evidence for a role in treating attention-deficit/hyperactivity disorder, delirium, and dementia.” (2)

• A 2020 review of results from 23 light therapy research projects concluded that it had a mild to moderate positive effect on non-seasonal depression. 

• A 2024 study found bright light therapy improved depression and focus. 

• If you are interested in theories of how light therapy helps, check out this 2011 article from the journal Neuropsychobiology. (3)

Standardized Light Therapy Lamp

Until recently, research on the effectiveness of light therapy for SAD and other conditions has been performed with a specific configuration of therapy lamp that was designed in the 1980s.

The light therapy lamp that is used in that research is placed 16 to 24 inches from your face. It has: 

• 10,000 lux light output,
• surface area of 1 ft by 1.5 ft, and
• a downward tilt.

Most of the modern light therapy lamps aren't as large and don't have the downward tilt.

How to Use a Light Therapy Happy Light 

Light therapy lamps are typically used daily first thing in the morning (or at least early in your morning) for about 30 minutes, though sometimes they are used for an hour or more. Less potent lamps will require longer exposure than those that have the recommended 10,000 lux output.

You can experiment to find the length of time that is ideal for you. Most people have positive results within between a few days and a couple of weeks. Increase or decrease your time exposure depending on your results.

The therapeutic use of the specialized lamp is all about light coming in through your eyes, but you do NOT want to look directly at the light.

"While your eyes must be open, don't look directly at the light box, because the bright light can damage your eyes." --Mayo Clinic light therapy advice

You need to be in a relatively inactive state while you use the therapy lamp so that it is close enough to be effective. While you're doing phototherapy you could read, check emails, eat breakfast, knit, work on the computer, watch TV,. . . These lamps are NOT intended to be used while you exercise or do things that require a lot of movement. 

Researchers recommend positioning the lamp on an angle facing down toward your face. There are very few models that are created with this downward bend. While the academic research on the usefulness of light therapy has been performed with lamps that tilt downward, my client's experience and the vast number of Amazon positive results reviews for boxes with a flat surface show that people are having success by merely placing the box to their left or right without the downward angle. 

Light therapy lamps that don't have the downward tilt are placed to the side of your face so that you are receiving the light in your peripheral vision (at angles equivalent to about 10:00 and 2:00).

Follow the manufacturer’s instructions about how far to place the lamp from your face. A 10,000 lux light with a large surface area (1 ft by 1.5 ft.) usually sits from 16 to 24 inches from your face. Lamps that do not throw as much light will be positioned closer.

Who Should Not Use Light Therapy

Light therapy is specifically NOT recommended for people with eye problems, light-sensitive skin conditions, and those on medications or supplements that make you light-sensitive. St John’s Wort is on the list of light sensitivity-causing supplements.

Discontinue use if you have any negative reactions such as too much energy, a hyper feeling, or mania.

While light therapy may help bipolar depression, consult with your doctor before giving it a try since it may trigger mania.

The Mayo Clinic has some useful info about how to handle negative side effects. 

Examples of Phototherapy Lamps

For examples of light therapy lamps, check out my blog post: Best Light Therapy Happy Lamps Reviews 

NOTES: This article is a summary of my research. It is NOT intended to replace consultation with your personal doctor or other medical professionals. Check in with your own doctor to find out if light therapy is a match for you. 

References

1) Targum, S. D., & Rosenthal, N. (2008). Seasonal affective disorder. Psychiatry (Edgmont (Pa. : Township)), 5(5), 31–33.

2) Schwartz RS1, Olds J. The psychiatry of light. (2015). Harvard Review of Psychiatry, 23(3):188-94. 

3) Pail, G., Huf, W., Pjrek, E., Winkler, D., Willeit, M., Praschak-Rieder, N., & Kasper, S. (2011). Bright-Light Therapy in the Treatment of Mood Disorders. Neuropsychobiology, 64(3), 152–162. doi: 10.1159/000328950 

4) Rosenthal, N. E. (1984). Seasonal Affective Disorder. Archives of General Psychiatry, 41(1), 72. 

5) Wehr TA, Skwerer RG, Jacobsen FM, Sack DA, Rosenthal NE. Eye versus skin phototherapy of seasonal affective disorder. (1987). American Journal of Psychiatry, 144(6), 753–757. 

6) Kripke, D. F. (1998). Light treatment for nonseasonal depression: speed, efficacy, and combined treatment. Presented at American Psychiatric Association Symposium 54, San Diego, California, May 20, 1997. Journal of Affective Disorders, 49(2), 109–117. 

7) Lewy, A. J., Bauer, V. K., Cutler, N. L., Sack, R. L., Ahmed, S., Thomas, K. H., … Latham Jackson, J. M. (1998). Morning vs Evening Light Treatment of Patients With Winter Depression. Archives Of General Psychiatry, (10), 890.

8) Penders, T. M., Stanciu, C. N., Schoemann, A. M., Ninan, P. T., Bloch, R., & Saeed, S. A. (2016). Bright Light Therapy as Augmentation of Pharmacotherapy for Treatment of Depression. The Primary Care Companion For CNS Disorders. 

9) Lam, R. W., Levitt, A. J., Levitan, R. D., Michalak, E. E., Cheung, A. H., Morehouse, R., … Tam, E. M. (2016). Efficacy of Bright Light Treatment, Fluoxetine, and the Combination in Patients With Nonseasonal Major Depressive Disorder. JAMA Psychiatry, 73(1), 56. doi: 

NOTE: I may receive a small commission for sales made from links on this page but it doesn't impact your cost or my decision to mention the product.

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