Seasonal affective disorder (SAD) is a type of depression in which the onset of depression symptoms generally occurs during the winter months, when there is less sunlight. Depressive moods usually disappear in the spring and summer (though, in rare cases, SAD can occur as a result of heat and humidity in the summertime). Light therapy is often an effective method of treatment for wintertime seasonal affective disorder and other types of depression.

What is Light Therapy?

Light therapy, also called “phototherapy,” involves exposure to bright artificial light radiating from a light therapy box. This light is much stronger than the lighting in your home or office. Light therapy imitates natural outdoor light, but is about five times more intense.

Researchers are not entirely clear on how this particular depression treatment works. Light therapy appears to:

  • Control the release of melatonin in the body (a hormone involved in mood)
  • Regulate your bodyÕs circadian rhythms (your internal 24-hour clock).

What to Expect from Light Therapy

Doctors generally recommend that an individual with seasonal affective disorder begin light therapy as soon as symptoms appear, generally in the fall or early winter months. You spend approximately 15 minutes to two hours by the light therapy box every day (Duration will vary depending on your doctorÕs recommendations.) Light therapy is most effective in the mornings, when it best aligns with your circadian rhythms.

Your eyes are kept open during treatment so that the light can enter them. However, looking directly into the light can damage your eyes. You donÕt have to sit immobile during light therapy–you can eat, read, work and generally continue your normal activities while you receive this depression treatment. According to the Mayo Foundation for Medical Education and Research, most people with SAD notice an improvement in their symptoms after just one week of light therapy.

Phototherapy Side Effects

Side effects of light therapy are uncommon, and generally mild when they do appear. Potential side effects include:

  • Agitation
  • Difficulty sleeping
  • Dry mouth
  • Fatigue
  • Headaches
  • Irritability
  • Nausea and vomiting
  • Strained eyes.

Side effects often disappear after a few days. You may also alleviate side effects by adjusting your distance from the light therapy box.

Light Therapy: SAD and Other Types of Depression

Light therapy is a convenient and inexpensive depression treatment for seasonal affective disorder (SAD) and other conditions, such as:

  • Depression in pregnant women and nursing mothers (who are concerned about taking antidepressant medication)
  • Jet-lag
  • Obsessive-compulsive disorder
  • Postpartum depression
  • Premenstrual dysphoric disorder (PMDD)
  • Some sleep disorders.

You should not use light therapy if you:

  • Are naturally sensitive to light or are taking medications that make you more sensitive to light
  • Have an eye condition
  • Suffer with bipolar disorder (light therapy can induce mania episodes).

Is Light Therapy Right for You?

Although you can purchase light therapy boxes without a doctorÕs prescription, itÕs best to consult a doctor before undergoing this method of depression treatment. Your doctor can help you maximize the therapeutic effects of light therapy by making recommends about the duration of therapy, the intensity of light required, and other details.


Mayo Clinic Staff. (2009). Is light therapy a good depression treatment option? Retrieved May 26, 2010, from the Mayo Clinic website:

Mayo Clinic Staff. (2008). Light therapy Ð Definition. Retrieved May 26, 2010, from the Mayo Clinic website:

National Institute of Mental Health (n.d.) What are the different forms of depression? Retrieved May 26, 2010, from the National Institute of Mental Health website:

Nemade, R. et al. (n.d.) Depression: Major depression & unipolar varieties. Retrieved May 5, 2010, from the website:

 Posted on : June 14, 2014