Light Therapy for Seasonal Depression (SAD)

Woman uses light therapy for seasonal depression in bethlehem pa

Light Therapy for Seasonal Depression

Light therapy treats seasonal affective disorder (SAD) through artificial light. This can be especially beneficial for those who experience SAD during winter or are not often exposed to direct sunlight. Talk to your doctor or mental health provider to see if light therapy might be a good option for you.

Table of Contents


How does light therapy work?

Light therapy, also known as bright light therapy or phototherapy, is a non-medication solution to a variety of different mental illnesses such as:

  • Seasonal Affective Disorder (SAD)
    • Also known as seasonal depression.
    • SAD is characterized in the Diagnostic & Statistical Manual of Mental Disorders under major depressive disorder with seasonal tendencies.
  • Insomnia/sleep problems
  • Other types of depression


It works by using a lightbox that mimics sunlight. This “fake” sunlight can provide similar benefits to the sun, such as vitamin D, increased serotonin, lower blood pressure, and improved sleep patterns. In addition, light therapy boxes are affordable, mostly ranging from $20 to $60.

Research shows that the lamp should be at least 2,500 lux to be effective. “Lux” is a unit of measurement for the intensity of light. For example, indoor lights tend only to give off 100-300 lux, while a springtime or summertime sun could give off 10,000-100,000 lux. This varies, depending on weather and location, so it is hard to pinpoint an exact intensity of sunlight. Light therapy boxes range most often from 2,500-10,000 lux.

For those who use a lamp with 10,000 lux, 30 minutes to 1 hour of exposure a day is usually recommended to see results. Light therapy boxes use white light, not ultraviolet (UV) or blue light.

A diffuser screen allows the light to distribute better into your eyes and around the room evenly. This gives these lamps the name of “boxes,” as opposed to purchasing a light therapy lightbulb alone. You would risk harm to your eyes and strain without this diffuser/filter, as it minimizes the strength of the light and absorbs UV rays.

Instructions on different brands of lightboxes differ, but in general, you must sit no more than 3 feet away from the box, and you can’t look directly into the light. Even though you shouldn’t stare at the light, your eyes must be exposed to it for the therapy to work. Try reading a book, doing work, watching TV, or eating a meal.

Light therapy is done in the comfort of your own home or office and does not require a mental health professional to oversee treatment. However, if used in conjunction with other treatments such as psychotherapy or medication, it’s essential to consult with your provider first.

The light stimulates the cells in the retina of your eye that connect to the hypothalamus. Your hypothalamus is the part of your brain that controls your hormone system and circadian rhythm, which is what tells our body to sleep at night and wake in the morning.

Activating the light in the morning, where most people report it to be the most effective, will restore your circadian rhythm and provide you with the benefits of the natural sun. In addition, this will help with seasonal depression symptoms by tricking your brain into thinking it’s receiving more sunlight.



Light therapy usually is not recommended if you have any of the following:

  • Sensitivity to the sun, sensitive skin
  • Are on medications that have symptoms of sun sensitivity
  • Eye conditions
  • History of skin cancer

Stop treatment and consult with a professional if you experience the following:

  • Euphoria
  • Intense irritability or anger
  • Mania
  • Eyestrain
  • Headache
  • Vision changes
  • Difficult time sleeping/fatigue
  • Jitteriness
  • Nausea
  • Skin rash


What is seasonal affective disorder (SAD)

More commonly known as seasonal depression, SAD is characterized by similar symptoms of major depressive disorder:

  • Feeling depressed or sad
  • Loss of interest in activities you once found enjoyable
  • Weight changes
  • Feeling sluggish, tired/poor sleep
  • Little to no energy
  • Feelings of hopelessness or worthlessness
  • Inability to concentrate
  • Thoughts of suicide or suicide ideation


SAD is primarily linked with the fall & winter season but can also occur during the spring & summer months and have varying symptoms.


  • Winter-pattern SAD
    • Oversleeping
    • Overeating
    • Weight gain
    • Introversion/social withdrawal


  • Summer-pattern SAD
    • Insomnia
    • Poor appetite
    • Weight loss
    • Restlessness
    • Anxiety
    • Agitation/violent thoughts or behavior

Note: Light therapy will not help summer-pattern SAD


Treatments for SAD:

  • Light therapy


  • Psychotherapy


  • It can help those suffering learn to manage their stress and symptoms through coping skills.


  • Medication


  • Certain antidepressants have been shown to help seasonal affective disorder. Consult with your doctor or mental health professional (such as a therapist or psychiatrist) if you’re interested in seeing if medication may help.


  • At-home treatments


  • Make sure your house gets enough light


  • Self-care


  • Physical exercise


  • Healthy diet


  • Socialize


How long does light therapy take to work?

Many people report experiencing a difference with light therapy within 3-5 days or the first week of use. Fatigue is expected in the first week since your body is getting adjusted to the changes in sleep-wake patterns. If you don’t see results in the first week, you may experience changes in the second week.

Finding the correct amount of time to use your light therapy box may take some trial and error. For example, lower lux lamps often require longer treatment times, whereas some people report results with a high lux (10,000) lamp after using it for only 30 minutes per day.

How long light therapy takes to work for you is dependent on the light therapy box you have, the ailment or illness you’re looking to treat, how often you use it, and what side effects you have.



Light therapy is an excellent option for people who experience seasonal depression during the winter season but do not opt for medication. It can also be used alongside other treatments like psychotherapy, medication, and other home remedies.

If you’re interested in starting light therapy at home, it’s best to consult with a medical professional who understands your SAD and its symptoms. However, no medical prescription is required to start this treatment.

Online Therapy & Telehealth in Pennsylvania

If you’re suffering from seasonal depression and are looking for counseling, consider Dr. John G. Kuna and Associates for online and telehealth therapy. We are a team of highly trained professionals, and with our virtual counseling services, you can receive the support you need, no matter where you are. Schedule an online appointment today and take the first step towards overcoming seasonal depression.

Brooke Lamberti

Brooke Lamberti is a content writer based out of Scranton, Pennsylvania. She received a Bachelor of Science in Psychology from Marywood University, and has prior career experience working in social work and domestic violence advocacy. She has a passion for writing and helping others.

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