Bright light therapy has long been a key treatment for seasonal depression. Now, new research adds to the evidence of its effectiveness for other types of depression. A study published in JAMA Psychiatry in late 2024, found that bright light therapy was an effective supplementary treatment for depressive disorders other than seasonal depression.

Researchers conducted a systematic review and meta-analysis of 11 randomized clinical trials involving data on more than 850 people. The studies compared bright light therapy (alone or in conjunction with an antidepressant) with an antidepressant alone, a dim red light, or a bright light placebo (negative ion generator). In the bright light therapy, study participants were exposed for at least 30 minutes a day to a fluorescent light box producing white light at 10,000 lux.

The study found that bright light therapy was associated with a 41% remission rate in people with nonseasonal depression, significantly higher than the rates for other treatment (23%). The response rate (a significant reduction in symptoms) was also significantly higher with bright light therapy (60% vs 39%) and response time to the initial treatment improved with the addition of bright light therapy.

Bright light therapy usually involves sitting near a lightbox or lamp during a 30-minute session each morning. A typical therapy light might provide exposure of 10,000 lux. By comparison, outdoor light exposure might be 1,000 to 10,000 on a cloudy day and 50,000 lux or more on a sunny day.

Light therapy has a number of advantages as a treatment approach including being accessible (it can be used at home with purchased or rented light boxes), noninvasive, and relatively safe with few potential side effects. Disadvantages of light therapy include that it needs to be used consistently, it may take some time to be effective, and it may not be covered by insurance. Some people shouldn’t use light therapy, such as people who have medical conditions that make eyes sensitive to light or take medications that increase light sensitivity. Talk with your doctor or a mental health professional before starting light therapy.

Other research has looked at the use of bright light therapy with various subgroups of people impacted by depression including children and teens, people with subthreshold depression, and older adults with Alzheimer’s disease and their caregivers.

• For example, one recent study looked at the impact of bright light therapy on depression symptoms and cognitive function in people with subthreshold depression. The study found that bright light therapy, compared to placebo, not only improved depressive symptoms, but also improved attention and vigilance (sustained attention). (Chen 2024)
• Depression also impacts many children and adolescents. Bright light therapy may also be a promising alternative treatment, according to a 2022 review study. The study found bright light therapy to be effective and well tolerated for children and teens. Similarly, another small study of adolescents with depression found that bright light therapy was safe and acceptable and was associated with decreased depression symptoms and improved sleep. (Ballard 2024)
• Perinatal depression, depression occurring during pregnancy or after childbirth, is common and often goes untreated. A recent small study found that bright light therapy also be effective in treating these depressions. Researchers found that morning bright light therapy was associated with a significant remission from perinatal depression and this effect was maintained across the perinatal period. (Garbazza 2022)
• Additionally, a recent study of the use of bright light therapy among adults with Alzheimer’s disease and their caregivers found that a four-week course of bright light therapy significantly reduced depression symptoms in people with Alzheimer’s and their caregivers. The authors note some of the advantages of bright light therapy, especially for this population: “As a non-pharmacological treatment, BLT can avoid the side effects and drug interactions associated with drug therapy, and also have the advantages of good compliance and ease of operation, making it suitable for use in patients with AD and their caregivers to treat depression.”