Light therapy, also known as phototherapy, is a treatment involving exposure to an artificial light source.
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.
- works on your biological clock by aligning your brain’s 24-hour cycle (aka circadian rhythm)
- balances the activation of serotonin circuitry in your brain, which is 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 the light wavelength, duration of use, and your personal circadian rhythm patterns.
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.
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:
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:
- problems with sleeping
- 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.
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
The negative aspects of light therapy are the side effects and complications that can occur. These include:
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.
Light therapy may be used as a stand-alone or add-on treatment.
While most research has focused on light therapy for treating MDD with seasonal patterns, academic research has
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 suffering from 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 2017 trial of people with bipolar I or II disorder found light therapy improved depression remission rates and lowered depression rates over a 6-week trial period. The light therapy was an adjunct to bipolar disorder treatment, and the researchers did not observe any changes in mood polarity.
Before you start light therapy, it’s a good idea to talk with a doctor or mental health professional. Light therapy may interact with other treatments you’re currently taking, such as medications.
Once you’ve had a doctor’s sign off, you can start by reading the instructions provided by the light box manufacturer.
A light with lower intensity may require longer exposure time — meaning you’ll have to sit in front of the box longer. The instructions can also help you identify specific risks and hazards for the brand of the light.
To use a light therapy lamp with 10,000 lux intensity, follow these steps:
- Place the lamp on a counter, desk, or other surface.
- Sit or stand at the correct distance from the lamp according to the manufacturer’s instructions.
- Keep your eyes open and do not sleep during light therapy sessions.
- Do not stare directly at the light box or lamp.
- Start with 30 minutes of exposure per day.
- 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. You can also try passing the time in front of the light box with an activity like reading a book or working, as long as you’re still facing the light.
Many people experience some benefits from light therapy within a few days.
Symptoms of depression should improve in about 2 weeks. If they do not, you can increase your time in front of a 10,000 lux lamp to 60 minutes per day. If this does not work, you can reach out to a doctor for advice.
If you find that light therapy works for you, you may want to make changes to the routine. For example, you can reduce the time in front of the lamp to 15 minutes, or schedule it at a different time of day.
You can also take a break from light therapy for a day or two. However, most people with MDD with seasonal patterns continue to use light therapy regularly over the winter (or days when there’s less sunlight available) to prevent symptoms from returning.
Light therapy may be used to treat major depressive disorder with seasonal patterns, sleep disorders, and other types of depression.
It’s often effective, possibly due to the effects on your circadian rhythm and levels of serotonin 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.