Fatigue, irritability... When light therapy can help us get through winter.
Low energy, trouble sleeping, anxiety... As winter approaches, and the lack of sunlight that goes with it, we can feel these symptoms. Light therapy can be a solution. Dr. Thomas Schwitzer, psychiatrist and hospital practitioner at the Centre psychothérapique de Nancy (Meurthe-et-Moselle), explains.
The days are getting shorter. Light is getting scarcer. In this winter period, some of us, affected by the lack of light, feel a drop in energy and, in more serious cases, find our sleep disturbed or even develop mood disorders. Light therapy can be a remedy for all these ailments.
If it's effective for the so-called winter blues, it's also effective in cases of more severe depression, confirms Dr. Thomas Schwitzer, psychiatrist, lecturer at the University of Lorraine and hospital practitioner at the Centre psychothérapique de Nancy (the adult psychiatry teaching hospital of Greater Nancy directed by Professor Raymund Schwan).
What are the effects of reduced light levels on individuals?
A whole series of symptoms can develop when a subject lacks light: a drop in energy, greater fatigue, greater sensitivity to stress, irritability... These are all things that can be experienced without falling into an illness such as depression. When people meet the criteria for depression, with slowed brain and body activity, sleep and appetite disturbances, loss of pleasure, inability to carry out activities of daily living, anxiety, and they meet the criteria for seasonality, i.e. they appear in winter but not in summer, we speak of "seasonal depression".
How can light therapy help people overcome the "winter blues" or so-called "seasonal depression"?
Light therapy, which involves the emission of light by a fixed device - a lamp - or a portable device - glasses - will provide the light that is missing as the days get shorter. This light penetrates the eye, and more specifically the retina, before reaching the centers that regulate circadian rhythms in the brain, i.e. the day-night and sleep-wake mechanisms. These rhythms are regulated by various external markers, the most important of which is daylight. When there are variations in daylight, the circadian clock is disrupted and upset. The aim is to resynchronize circadian rhythms by regulating chemical molecules in the brain. The main chemical molecule affected is melatonin. Light therapy will restore and rebalance melatonin secretions over the course of a day (day and night).
Can light therapy also treat non-seasonal depression?
Absolutely. Light therapy can treat low energy in winter and, at a more advanced stage, seasonal depression. Today, it is also indicated for the treatment of non-seasonal depression. Recent studies have demonstrated the efficacy and benefits of light therapy in the treatment of depression, with or without medication. Today, there are a number of patients who do not respond to antidepressant treatment, or who respond inadequately. The origin of the depression may then be different. The melatonin pathway, regulated by light therapy, can be explored.
What are the rules to follow when using light therapy?
Light therapy is used once a day, preferably in the morning, as soon as possible after waking up (traditionally between 7 and 9 a.m.), for 20 to 30 minutes over several weeks. The first effects, notably on energy levels and sleep-wake rhythms, can be felt very quickly after a few days' use.
Can we trust the devices on the market?
The devices meet the quality criteria of a light therapy lamp, and both fixed and portable devices are designed to deliver the right amount of light energy for therapeutic function. Fixed lamps emit a white light with an illuminance of around 10,000 lux. This treatment is well tolerated.