Light therapy can treat Seasonal Affective Disorder (SAD), also known as seasonal depression or winter depression.

Common symptoms of winter depression are:

  • Lack of motivation and energy

  • Decreased libido

  • Difficulty getting sleep

  • Difficulty waking up

  • Fatigue

  • Increased appetite

  • Sullenness

  • A desire to remain indoors

Unlike nonseasonal depression, symptoms of SAD aren’t felt all year. They usually begin in autumn and tend to disappear at the onset of spring.

What is Light Therapy?

Light therapy, also known as light box therapy or blue light therapy, involves working or sitting near a bright light that typically mimics daylight for a given amount of time.  It’s believed to ease depression symptoms by impacting chemicals released by the brain, which affect a person’s sleep and mood.

Research: The Effectiveness of Light Therapy

Clinical trials studying the effectiveness of light therapy for individuals with MDD (Major Depressive Disorder) have been positive.

In one study that involved 50 inpatients diagnosed with severe MDD, researchers found that when they combined venlafaxine, an antidepressant, with light therapy, the patients experienced “significantly lower HDRS (Hamilton Depression Rating Scale) depression scores” as compared to when they took the antidepressant alone.

In another trial that lasted 8 weeks, 122 participants with non-seasonal MDD reacted positively to light therapy combined with SSRI fluoxetine or light therapy on its own.  The treatment was well tolerated and effective among the participants.

Kripke, a professor of psychiatry at the University of California, San Diego, together with his colleagues, carried out a 1-week study in 1992. The study involved veterans diagnosed with depression. Patients with depressed forms of bipolar disorder or nonseasonal major depressive disorders were admitted to the Veterans Affairs Medical Center.  25 patients were randomly treated using bright light therapy of about 2,000 to 3,000 lux, while 26 patients were randomly exposed to dim red-light treatment in a placebo.  In just one week, the 25 patients placed under the bright light treatment had an 18% reduction in their depression scores, whereas the other 26 who were placed in a placebo didn’t show any improvements whatsoever.

According to most studies, almost 75% of people with SAD experience significant improvements after using light therapy.

What to Expect

Light therapy, when used consistently, eases the symptoms of SAD and helps you feel better.

Choosing a Light Therapy Box

You don’t require a prescription to purchase a light box. However, it’s advisable to ask your healthcare provider or doctor whether you should use this technique and the type of lightbox that’s suitable for your needs. Before treatment commences, discuss with your doctor any special precautions.  Also, follow the manufacturer’s instructions.

A light box should:

  • Emit the least possible amount of UV

  • Provide a light exposure of 10,000 lux.

Recommendations for using a light box include:

  • Your eyes should be open, although not looking directly into the light.

  • Doing it consistently

Side Effects of a Light Box

Although the side effects are generally mild and uncommon, users sometimes experience:

  • Headaches

  • Dry eyes

  • Insomnia

  • Eyestrain

  • Irritability

Sitting or working farther away from the light and reducing the treatment duration usually eliminates the effects.

What Conditions Can Light Therapy Be Used For?

In addition to treating Seasonal Affective Disorder, light therapy has other uses, including:

  • Treating other forms of depression

  • Used together with antidepressant medication to boost the effectiveness of the treatment

  • Substituting antidepressants for women who are pregnant or breastfeeding

  • Helping patients with depression lower their antidepressant dosage

  • Used as an alternative treatment for depression because it’s safe and has fewer side effects

When to Use with Caution

It’s always best to talk to your doctor before using light therapy, especially if:

  • You are taking medications that increase your sensitivity to light, for instance, herbal supplements, anti-inflammatory medications, or antibiotics

  • Your skin is sensitive to light. One such skin condition is systemic lupus erythematous

  • You’ve got an eye condition that makes your eyes sensitive to light

What Determines the Effectiveness of Light Therapy?

Three main elements enhance the effectiveness:

  • Intensity– An intensity of 10,000 lux of light at a distance of 41-61 cm from the light box is optimal.

  • Duration– 20-30 minutes of light exposure to 10,000 lux of light is recommended daily. If the intensity is much lower, then you may need longer sessions.

  • Timing-It’s best to start your therapy sessions early in the morning as soon as you wake up. Your doctor can help you set up a schedule that best suits you.

How to Benefit from Light Therapy

To help make light therapy a success, you can take the following steps:

Maintain Consistency

Sticking to a routine will maximize the benefits of using light therapy. If you have a tight schedule, you can skip a day or two, however, monitor your progress.  With your doctor’s help, you can devise a way to schedule your daily sessions.

Buying the Right Box

Talk to your doctor before buying a light box. That way, you’re sure to get a box that’s safe and effective. By doing the research before getting a lightbox, you’ll ensure that you buy a box that has the right type of light with the recommended brightness.

Track Time

If you stop your light therapy as soon as spring starts or you interrupt the sessions during winter, any improvements you may have made may be reversed, and your symptoms may return.  Track when you begin during fall and when you stop in spring. Hence, you’ll be able to know when to start and stop come the following year.

Incorporate Other Treatments

To improve your condition, you may require additional treatment. Your doctor will advise you on other treatment options such as psychotherapy and antidepressants.


With light therapy, you’ll see improvements in just a few days. However, noticeable changes might take 2 or more weeks, depending on an individual.


Medical disclaimer:

Sunshine Behavioral Health strives to help people who are facing substance abuse, addiction, mental health disorders, or a combination of these conditions. It does this by providing compassionate care and evidence-based content that addresses health, treatment, and recovery.

Licensed medical professionals review material we publish on our site. The material is not a substitute for qualified medical diagnoses, treatment, or advice. It should not be used to replace the suggestions of your personal physician or other health care professionals.

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