Light therapy (phototherapy) for many types of depression may have fewer and milder side effects and work more quickly than traditional depression treatments. Talk with a doctor before use.

Light therapy (phototherapy) involves exposure to an artificial light source.

Many types of light therapy are available to treat several conditions, including sleep disorders and types of depression.

Light therapy primarily treats major depressive disorder (MDD) with seasonal patterns (formerly known as seasonal affective disorder, or SAD).

Research on light therapy gives a few reasons why it may improve the symptoms of depression. It:

  • works on your biological clock (circadian rhythm) by aligning your brain’s 24-hour cycle
  • balances the activation of serotonin in your brain, a key component in mood regulation
  • contributes to stable and consistent sleep patterns
  • increases alertness

The extent to which light therapy works for you depends on:

  • light wavelength
  • duration of use
  • personal circadian rhythm

You sit near a lightbox or lamp during a session. The lightbox usually mimics natural sunlight, but devices can vary.

The standard output of a light therapy box is between 2,500 and 10,000 lux, a measure of light brightness.

Treatments usually begin in the fall and continue until early spring. The length of the session depends on how you handle the treatment and the strength of the lightbox.

Guidelines for typical bright light therapy usually suggest starting with 10,000 lux for 30 minutes every morning, but someone new to the method may require shorter exposure.

The more powerful the lightbox, the shorter the treatment session might be.

Some people shouldn’t use light therapy, especially those who:

If you’re considering this therapy, consult a doctor if you have:

Irritability or euphoria are also signs to stop using the lightbox and speak with a doctor.

For those who can use light therapy, potential side effects still exist. You can manage these by adjusting the duration, intensity, or timing of the sessions.

Mild but rare side effects may include:

You can discuss these side effects with a doctor, but you might also find relief through simple changes. For example:

  • Avoid using the lightbox before bedtime to prevent insomnia.
  • Place the lightbox further away to prevent eyestrain and headaches.

Pros

Light therapy is:

  • Accessible: You can perform the treatment at home at any time using rented or purchased lightboxes. You can also stop light therapy for a few days without adverse effects or the return of symptoms.
  • Noninvasive: It provides an alternative or add-on to medical interventions like medications but isn’t taken internally.
  • Safe: Despite possible side effects, especially with incorrect lightbox use, light therapy is generally safe and low risk.
  • Associated with few or mild side effects: Most side effects are preventable by adjusting how you use the lightbox.

Light therapy has potential uses beyond MDD with seasonal patterns. It’s always important to discuss starting any new therapy with your doctor.

Cons

The negative aspects of light therapy are the side effects that can occur.

Insurance may not cover the cost of a lightbox, even if your doctor prescribes it. This expense can be a barrier for some people.

Achieving results with a lightbox takes time — at least a few days. Getting a benefit from the lightbox requires consistent use at the same time every day.

While most research has focused on light therapy for treating MDD with seasonal patterns, light therapy may also help with:

Dr. Carl Vincent, a psychologist in Moline, Illinois, suggests that light therapy be used with other treatments, such as psychotherapy or a drug regimen.

“The idea is that it could be used as a supplemental therapy,” Vincent says. “In addition to treatment, people coping with depression in the winter months should try to be more active. Winter is a time when people tend to be more sedentary, and getting more exercise can help improve mood.”

A 2018 research review suggests that light therapy may effectively treat MDD with seasonal patterns and non-seasonal MDD. It may have fewer side effects than traditional depression treatments and act more quickly, too.

Light therapy may also be used with other treatments. The same review suggests combining psychopharmacological treatments with light therapy may benefit those with major depression.

Talk with your doctor or a mental health professional before starting light therapy. It may interact with other treatments you’re currently doing.

Once cleared, start by reading the lightbox instructions for use. The instructions can help you identify specific risks and hazards for that brand.

To use a lightbox with 10,000 lux intensity, follow these steps:

  1. Place the lightbox on a flat surface.
  2. Sit or stand at the correct distance from the lightbox according to the instructions.
  3. Keep your eyes open. Do not sleep during light therapy sessions.
  4. Do not stare directly at the lightbox.
  5. Start with 30 minutes of exposure daily, or as recommended.
  6. Schedule light therapy sessions as soon as possible after waking up, between 6:00 a.m. and 9:00 a.m.

You can adjust this schedule and the duration of sessions according to how you feel. A lower-intensity lightbox may require longer exposure time.

You can pass time in front of a lightbox with an activity like reading or working, as long as you’re still facing the light.

Symptoms of MDD with seasonal patterns should improve in a few days to a couple of weeks. You can increase your time in front of a 10,000 lux lightbox to 60 minutes daily if they don’t. Contact a doctor if this also doesn’t work.

If light therapy works for you, you might want to change your routine. For example, you can reduce your exposure to 15 minutes or schedule it at a different time of day.

You can take a break from light therapy for 1 to 2 days if needed. Most people with MDD with seasonal patterns continue to use light therapy regularly over the winter (or days with less sunlight) to prevent symptoms from returning.

Light therapy may be used to treat major depressive disorder with seasonal patterns, sleep disorders, other types of depression, and chronic or inflammatory conditions.

It’s often effective, possibly due to its effects on your circadian rhythm and serotonin levels in the brain.

Light therapy may have several side effects, but most of these are mild and can be prevented. Talk with a doctor if you feel light therapy might be a good treatment option for you.