Light Therapy and Mental Health

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In this article, we take a look into the link between light therapy and mental health. Read on to know how light therapy can help with mental health.

The biological clock we have helps us keep the rhythm of our bodies and the sleep-wake cycle in line with the light-day cycle of the planet. This body clock is located in the part of the brain that controls hormones, the suprachiasmatic nucleus (SCN).

Old Man Sleeping

The light that gets through to the eye is responsible for activating this part of the brain which in turn cuts down on the production of hormones responsible for sleep that is made in the pineal gland of the brain. This light is also responsible for the release of many other hormones and can also affect the temperature of the body.

We are programmed in such a way that we will cycle every 24.2 hours- but if we get enough exposure to light on a daily basis, our cycles will be more in line with the rhythm of the earth. There are four neurotransmitters that are responsible for making sure the biological clock is working properly. They are dopamine, norepinephrine, glutamate, and GABA.

It is very important to note here that melatonin will not be produced properly if there are not enough thyroid hormones present in the body. So if someone is experiencing sleeping problems, they should get their thyroid hormone levels checked and also note down how much light they are getting each day.

As a general rule of thumb, the more bright light one gets during the day the more melatonin they are likely to produce and have in their bodies when it is time to sleep at night. This will also make the person much less sensitive to lower exposure to light in the evening or at night.

What is Light Therapy?

Light therapy is a type of therapy that makes use of specialized artificial light to help people suffering from mood disorders, make changes to their biological clock or even synchronize a person’s cycle of sleeping and staying awake with the day/light cycle of the earth. Although there is room for more research to be conducted on this, light therapy has also been known to be useful in normalizing sleep and also calming down people who suffer from dementia.

This artificial light is made up of either a lightbox that produces up to 10,000 lux of light or it can be of a much lower intensity that is made up of specific wavelengths of light. This may be light from the blue or from the green parts of the visible spectrum.

The video below shows further info about light therapy.

Synchronizing Sleep Cycles

If someone wants to sleep at a later time and delay the onset of sleep, the best way to use light therapy for that person’s case would be to use light therapy right before bedtime. On the other hand, if someone wants to bring about their time to sleep a bit earlier in the day/night cycle, it may be a better idea to have their light therapy sessions be in the second part of the night.

Old Woman Waking Up Happy


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Treating Mood Disorders

A person is thought to be suffering from seasonal affective disorder when that person exhibits signs of depression only at particular times of the year, with the symptoms completely going away at other times of the year. In order to be diagnosed with this disorder, the person needs to feel this way for at least two years consecutively.

In reality, most people who suffer from depression will have a seasonal component in their depression but it may often not fit the strict criteria of seasonal affective disorder (SAD). A lot of studies have shown that people who do suffer from SAD will be better off with light therapy sessions.

Light therapy, while effective, cannot replace the traditional treatment modalities of non-seasonal depression and even in the case of seasonal depression, this should not be the only form of treatment. People who are more prone to oversleep and overeat, have been known to be more responsive to light therapy than people who do not.

If light therapy is being administered for treating mood disorders, it is best to give light therapy for a total duration of 30 minutes for every hour that the patient sleeps for more than 6 hours. So let’s say a person sleeps for 8 hours, so that person will need an hour of light therapy per day to experience the benefits of this therapy method.

An important thing to consider here is that people who have the tendency to oversleep should be given a light therapy device that simulates the light of dawn.


For people who suffer from dementia, bright light between 7-9 pm can really help them sleep much better and also have fewer incidents of nighttime awakenings. Dementia patients can also get another benefit of light therapy which is that it can slow down the decrease in cognitive functioning that occurs mostly at night. Light therapy is also said to have a calming effect on those suffering from dementia.


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What Kind of Light to Use?

You will need a specialized light therapy lamp for effective light therapy. Some people have known to use a night light for this but the best results can be had from a dedicated light therapy lamp.

Most of the early studies into this type of therapy used 10,000 lux (a measure of the intensity of the light) broad-spectrum light which was kept at a distance of two feet from the eye. A few recent studies are showing that light with lower intensity can also help and be just as effective.

Light that has shorter wavelengths (like the blue part of the spectrum) is thought to be the most active part of the spectrum of light that has a direct impact on the sleep/wake cycles. Most of the commercial light therapy devices available for SAD operate at between 5,000 to 10,000 lux.

So, as we have discussed in this article, light therapy can be a good supplemental treatment method for many mental health disorders. It can really help fix the body’s biological clock and has been shown to be effective in treating SAD as well as non-seasonal depression.