Autumn is here again. Its dead leaves, its rain, its gray sky. While some enjoy this season and take the opportunity to stay warm watching a series under a blanket, others are deeply depressed due to the low light. Low morale can lead to seasonal depression. To combat this pathology, manufacturers have created lamps producing light rays to mimic the effects of the sun.
The promise: by exposing ourselves every morning, early, for at least thirty minutes, to a screen diffusing white light, our morale will soar. Are these machines, available in supermarkets, really effective, or are they pure gadgets? We asked two doctors the question.
More effective than antidepressants
“Heliotherapy has been practiced since Antiquity,” says Pierre Alexis Geoffroy, professor of psychiatry at the Bichat AP-HP hospital and at the ChronoS center of the GHU Paris psychiatry neuroscience. The sun has always been used as an antidepressant. » What has changed recently is the data. Over the past thirty years, evidence of the effectiveness of light therapy has been accumulating, notably thanks to several clinical studies.
Pierre Alexis Geoffroy led a study whose result is clear. “In depression, whether seasonal or not, light therapy has an effect comparable to antidepressants. And the two joint treatments are more effective than antidepressants alone. » If light therapy was already used to treat seasonal mood disorders, it could therefore become a therapeutic solution for all kinds of depression, including peri and postpartum depression.
Resynchronize biological rhythms
How to explain these results? To understand it, we must already know how our biological rhythm works. When there is little light, we secrete melatonin, the hormone that signals that it is dark and makes us sleep. In summer, in the morning, the sun gives a signal to our body, which will then inhibit the secretion of this hormone. In winter, the sun rises later, melatonin is secreted longer, and we are therefore more tired.
“The chronobiological rhythms are shifted in depression because we sleep less well and the disruption of these rhythms alters our mood,” adds Antoine Pelissolo, psychiatrist and head of the psychiatry department at Henri Mondor hospital, in Créteil. “Getting light in the morning resynchronizes biological rhythms and therefore indirectly reduces depressive symptoms. »
But that’s not all. “We recently discovered that there are direct pathways between the retina and other centers in the brain, in particular emotion regulation centers,” continues the professor of psychiatry at Bichat hospital. “One of the hypotheses is that the rays have an effect on certain neurotransmitters,” says Antoine Pelissolo. These rays would notably strengthen serotonin, the substance most involved in the treatment of depression. »
No side effects
Unlike antidepressants which can cause side effects, light therapy lamps do not generate any. “Only headaches and other fairly banal symptoms that we also find in people who have taken placebos have been reported,” assures Antoine Pelissolo.
Be careful, however, to use safe lamps, with the European Conformity (CE) standard. If the products are properly calibrated, there is no risk of retinal burn. “The sun at noon has a brightness of 100,000 lux,” recalls Pierre Alexis Geoffroy. Light therapy is only 10,000 lux for thirty minutes. »
However, some people should avoid using these products. Those with eye pathologies, such as age-related macular degeneration, cataracts, retinopathy or glaucoma, for example, will have to do without it due to the intensity of the light. Those suffering from bipolar disorder should, for their part, be careful. “There is a small risk of a manic turn, as with all antidepressant strategies,” underlines the psychiatrist. The risk is that the antidepressant exceeds its effect because it is a fairly stimulating treatment. » No lamps for them therefore without a mood regulator to regulate moods.
Towards a replacement of antidepressants?
Not sure, however, that UV lamps will replace antidepressants in medicine cabinets anytime soon. “With each article on the subject, patients want to stop their treatment to be put on light therapy,” testifies the professor of psychiatry at Bichat hospital. It is an effective treatment. An additional tool for anti-depressive strategies. If antidepressants work, they should be kept. Furthermore, light therapy can be combined with antidepressants. » The lamps are also useful for people in specific periods of life who require care with few side effects, such as pregnant women or the elderly.
“You should not rely exclusively on light therapy,” confirms Antoine Pelissolo. If the depression is not too advanced, we can start with that. But if the condition does not improve, you should not wait too long to discuss another treatment with your doctor, whether medication or therapy. » The psychiatrist also advises using these lamps preventively. “People who know that they have a slump every December can start to expose themselves in advance. » Only problem: the cost of these devices, varying from 50 to more than 200 euros. Unlike Switzerland, England or the United States, they are not reimbursed in France, even with a medical prescription.