Light Therapy

Light therapy, also known as phototherapy, is a treatment involving exposure to an artificial light source.

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

This is a type of depression that occurs during a certain time of year, usually in the wintertime when there’s less daylight. Light can also be used to treat other conditions, including sleep disorders and other types of depression.

How it works

Light therapy compensates for the lack of exposure to sunlight that may contribute to major depressive disorder with seasonal patterns.

During a session, you sit near a light box or lamp, which emits bright light. The box or lamp usually mimics natural sunlight, but there can be variations between devices made by different manufacturers.

The standard output of a light therapy box is in the range of 2,500–10,000 lux. A lux is a measure of light brightness.

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

Guidelines for typical bright light therapy will usually suggest starting with 10,000 lux for 30 minutes every morning, but someone new to the method may require shorter initial treatments. The more powerful the light box, the shorter the treatment session may be.

Side effects

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

have medical conditions that make eyes sensitive to light
take medications, like some antibiotics or antipsychotics, that increase light sensitivity
If you’re considering this therapy, you should consult a doctor if you have any of the following conditions:

• sensitive skin
• eye conditions
• a history of skin cancer

Some people may also experience euphoria or irritability, which is a sign to stop using the device and speak with a doctor.

For those who can use light therapy, there are still potential side effects. Usually, these can be dealt with by adjusting the duration, intensity, or timing of the sessions.

Side effects may include:

• headaches
• eyestrain
• agitation
• irritability
• problems with sleeping
• fatigue
• blurry vision

You can discuss these side effects with a doctor, but you may also find relief through some simple changes. Avoid using the lamp before bedtime to prevent insomnia, and place the light box further away from you to prevent eyestrain and headaches.

Pros of light therapy

In addition to the possible benefits for improving depression symptoms, light therapy is generally easy to start and adjust according to how it makes you feel.

Light therapy is:

• Accessible. The treatment can be done at home using rented or purchased light boxes.
• Noninvasive. It provides an alternative or add-on to medical interventions like medications, but is not taken internally.
• Safe. Although there are some possible side effects, especially when the lamp is used incorrectly, light therapy is generally safe and low-risk.
• Convenient. You can use a light therapy lamp at home, while you read or eat breakfast. You can also stop light therapy for a few days without adverse effects or the return of symptoms.
• Associated with few or mild side effects. Most of light therapy’s side effects, like headaches, dizziness, or nausea, are preventable by adjusting how you use the lamp.

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

Cons of light therapy

The negative aspects of light therapy are the side effects and complications that can occur. These include:

• headache
• insomnia
• fatigue
• eyestrain
• euphoria
• irritability

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

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