When our bodies don't receive enough light, approximately one in ten of us experience depressive symptoms. Light therapy has the ability to kickstart our circadian rhythm and get us back on track.
In our latitudes, there is a scarcity of light during the winter season. Unfortunately, some individuals are particularly sensitive to the lack of light. When they are exposed to a certain amount of light, they experience what is known as winter depression. The typical symptoms of winter depression include feelings of sadness and irritability, increased need for sleep, quick fatigue, heightened appetite, and cravings for sweet treats. When winter depression strikes, it is important to seek treatment. In recent years, light therapy has gained recognition as a treatment option alongside traditional medication. Leading the way in this field is Dr. Klaus Martiny, a prominent advocate for light therapy in the treatment of depression.
The results of light therapy speak for themselves
According to Klaus Martiny, nearly all individuals affected by depression experience sleep problems. Our sleep is closely linked to our circadian rhythm, which is regulated based on the amount of light we are exposed to. Special cells in our eyes absorb the light and send signals throughout our system. The body's genetic clocks initiate the physiological processes that include the production of the sleep hormone melatonin and the stress hormone cortisol. Light therapy helps create balance in the circadian rhythm, which in turn regulates hormone production.
— Light therapy emerged as a significant treatment method in the USA between 1986 and 1988, and I have personally been working with light for ten years. At a world congress in Hamburg, I attended a presentation by Professor Anna Wirz-Justice from the Psychiatric Hospital in Basel, where she discussed the effectiveness of light therapy for depression. This inspired me to delve into the field. Initially, there were sceptics who doubted the efficacy of light therapy, but today the results speak for themselves, he states.
The third eye distinguishes between light and darkness
— Chronobiology, the study of our internal body clocks, is an emerging field of research, Klaus Martiny explains, adding:
— Melatonin plays a crucial role in regulating our circadian rhythm, and as we know, depression is often associated with disruptions in our body's natural rhythm.
The process of how our eyes absorb light is fascinating. It has been discovered that we actually have a "third eye" that is not related to vision. This third eye is located in the ganglion cells of our eyes, which contain special photopigments. Interestingly, certain living lizards, like iguanas, also have a third eye, known as the "parietal eye," on top of their heads. This eye allows them to distinguish between light and darkness."
"Nothing compares to natural sunlight"
— Since I started using light therapy ten years ago, there have been no significant advancements in light devices. While the intensity and colour of the light can be adjusted, nothing compares to the natural light we receive from the sun, which cannot be replicated indoors. However, we can come close to artificial light with similar properties. For effective light therapy, a minimum of 10,000 lux is needed for half to a full hour, preferably in the morning. The majority of patients with winter depression who undergo light therapy experience noticeable improvements. Every person is equipped with light-sensitive clock genes, and it is possible to determine whether one has long or short clock genes. Individuals with long clock genes, which regulate longer circadian rhythms, benefit the most from light therapy, explains Klaus Martiny.
Combining light and wake therapy
— Another good tip for combating winter depression is to take a twenty-minute walk outside in the light, says Klaus Martiny, continuing:
— Our well-being generally worsens without light. This also applies to people who work at night and sleep during the day. Everything suggests that working at night is unhealthy. Biologically, humans are designed to sleep at night. And at night, it should be dark.
The term light pollution is used when there is too much light at night. It has a negative impact on our production of melatonin, which among other things is an anti-cancer substance, and it disrupts the body's balance.
— The clinical studies I have conducted demonstrate a positive effect of light therapy. Most recently, I have combined light therapy with the so-called wake therapy. This involves keeping patients awake throughout the night, followed by light therapy in the morning. It has been shown that a significant number of depressed patients experience noticeable improvements from wake therapy combined with light therapy, but light therapy itself has an effect. However, one should not experiment with wake therapy on their own, as it is still an experimental treatment, concludes Klaus Martiny.
About Klaus Martiny
For the past ten years, Dr. Klaus Martiny has been working at the Psychiatric Research Unit in Hillerød, publishing numerous articles in international journals. He has also been involved in the development of the Danish reference program for unipolar depression. Dr. Martiny serves as the coordinating investigator for the current multicenter study (DUAG-7) of the Danish University Antidepressant Groups (DUAG). Additionally, he is a member of the Ethics Committee in the Capital Region and an external clinical lecturer at the University of Copenhagen.