The Benefits Of Light Therapy For Seasonal Affective Disorder

Medically reviewed by Laura Angers Maddox, NCC, LPC
Updated March 13, 2023by BetterHelp Editorial Team

Seasonal affective disorder (SAD) is a type of depression that coincides with the change of seasons. While many people with SAD experience symptoms during the fall and winter months, some may develop this disorder during the spring and summer. SAD usually causes typical depressive symptoms such as excessive sleeping, mood swings, feelings of sadness and hopelessness, and low energy. However, light box therapy can be an effective treatment for SAD by helping to regulate the body's circadian rhythm and improve mood.

While both psychotherapy and medication may be used as interventions for SAD, the first line of treatment prescribed by clinicians is typically phototherapy, or light therapy. For many people, light therapy relieves their symptoms of depression quickly without the need for medication or other additional treatment. The most common tool used for light therapy is a light box or “SAD lamp”, which emits a specific type of bright light and can be used daily in your home. Read on to learn about the potential benefits of this type of therapy for seasonal affective disorder.

How Can Light Therapy Help You Overcome Symptoms of Depression?

What Causes Seasonal Affective Disorder?

As the seasons change from summer to fall, the days get shorter and the amount of exposure we get to the light of the sun decreases. For some people, these changes can lead to a series of mood-related symptoms, such as feelings of sadness and hopelessness, lethargy, carbohydrate cravings, and excessive sleeping. These symptoms may indicate that a person is experiencing SAD, or seasonal affective disorder. For those with summer SAD, it may actually be the extended exposure to sunlight that leads to these symptoms.

While researchers are still trying to understand why this disorder develops, studies have revealed that a lack of exposure to sunlight can disturb the patterns of a person’s circadian rhythm—or the natural, internal process that manages our sleep patterns. In turn, this disruption can affect serotonin and melatonin levels in the brain. Both of these are important neurotransmitters that play a pivotal role in managing sleep and mood. 

Why Light Therapy Works

A therapeutic light box can help alleviate symptoms of the seasonal affective disorder by mimicking natural light. Research suggests that light therapy for depression enhances mood by helping align a person’s sleep-wake cycle and balancing serotonin activity within the brain.

While antidepressants, psychotherapy, and lifestyle changes may also be recommended for those experiencing SAD, phototherapy is typically the first line of defense. 

Note that per an article from the University of Saskatchewan’s College of Medicine, phototherapy can be effective for treating SAD during winter months. However, the article also says that seeking additional treatment from a mental health professional for symptoms that persist year-round is recommended, since SAD may actually be clinical depression that’s intensified in certain seasons.

How Phototherapy Light Boxes Work

A light box or visor (a portable, head-mounted light) is typically used for phototherapy. All the individual has to do is sit near the box or wear the visor and naturally absorb the bright light it emits. These devices typically provide exposure to 10,000 lux (the standardized measurement of light levels) of light while also emitting a small, safe amount of UV light. For many people and with regular, proper use, it’s enough to reinstate a healthy circadian rhythm and adequate levels of serotonin and melatonin in the brain.

It’s important to use a light therapy box in the morning only, since using it later in the day or at night can negatively impact your sleep. As little as 20–30 minutes of light therapy per day can meaningfully reduce symptoms of SAD in as little as a few days or a couple of weeks in some cases. 

Choosing And Using A Light Box

Light boxes are designed to be safe. However, keep in mind that the FDA does not control them, so it’s best to talk to your doctor or a qualified mental health professional first before using one.

This is especially true if you have certain conditions like glaucoma, cataracts, a history of lupus, or sensitivity to sunlight, any of which could be exacerbated by use of a light box.

If your doctor or psychologist has recommended you use a light box, there are a few things to take into account when selecting and operating one. First, make sure that your box was explicitly built for treating SAD. Some similar devices are created for skin disorders, for instance—which could not only be ineffective in treating this disorder, but could damage your eyes. If you’re unsure about which light box might be best for you, ask a qualified healthcare provider for a suggestion.

Make sure to follow the instructions that come with the unit, along with any tips from the health professional who recommended it to you. Common safety precautions include:

  • Keep the light therapy box 16–24 inches away from your face

  • Keep your eyes open, but do not look directly into the light

  • Do your best to remain relaxed and avoid stress while using the box

  • Avoid blue light from nearby TV or phone screens during use

  • Contact your doctor if you experience side effects

How Can Light Therapy Help You Overcome Symptoms of Depression?

Other Types Of Therapy To Consider

With regular use, seasonal affective disorder light therapy can significantly reduce or even eliminate symptoms of seasonal affective disorder in some individuals.

However, phototherapy is not a replacement for psychotherapy or other recommended treatments for certain mental health conditions. Remember, it’s possible that symptoms of SAD could actually be worsening symptoms of a broader depressive disorder, which will typically not resolve without professional treatment. If you suspect you may be experiencing some form of depression or another mental illness, it’s wise to consult with a mental health professional for an evaluation. 

People with depression may sometimes have trouble finding the energy to attend in-person therapy appointments on a regular basis. For situations like these, or those where the individual simply prefers to speak with a provider from the comfort of their own home, online therapy is a viable alternative. Research suggests that virtual therapy can offer similar benefits to in-person sessions for conditions like depression and anxiety. If you’re interested in trying the online therapy format, you might consider a platform like BetterHelp. You can get matched with a licensed therapist who you can speak with via phone, video call, and/or online chat about any symptoms of a mental illness that you may be experiencing, or any other mental or emotional challenges you might be facing.


Phototherapy, or light therapy, is a simple but often effective treatment for those experiencing seasonal affective disorder. If you believe you may have this condition, it’s best to speak with a doctor and/or mental health professional before pursuing any type of treatment.

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