Light therapy for winter depression is a procedure that forms a subfield of light therapy. It is formally similar to bright light therapy, but is specifically designed for winter depression. Winter depression, also known as seasonal affective disorder (SAD), is a condition that results from a daily lack of sunlight. This lack of light can be compensated for with targeted light therapy to restore the patient’s disturbed biorhythm and thus his or her sense of well-being. The following explains the mechanism of development of winter depression: In healthy people, daylight has a direct influence on the internal clock and thus determines the biorhythm. This clock is located in the central nervous system (brain) in the hypothalamus, and is called the nucleus suprachiasmaticus. It is a nuclear area (collection of nerve cell bodies) whose cells control the pulsatile release of the hormone melatonin during darkness. The cells that make melatonin are called pinealocytes and are located in the pineal gland in the central nervous system. The cells of the suprachiasmatic nucleus, in turn, are connected by nerve fibers to the retina (retina), the sensory epithelium of the eye, and can thus register light conditions. The hormone melatonin is the timer of metabolism and has a circadian, sleep-promoting effect. The synthesis (production) of melatonin takes place from serotonin, a biogenic amine that, among other things, increases the sense of well-being. In the absence of light, the concentration of melatonin increases, while the concentration of serotonin decreases. This constellation can trigger depression, which occurs, for example, in the winter months when there is not enough daylight and is known as seasonal affective disorder (SAD). These are seasonally linked depressive phases of greater or lesser severity, characterized by the following symptoms:
- Fatigue
- Increased need for sleep
- Listlessness
- Difficulty thinking and concentrating
- Libido weakness
- Cravings
- Weight gain
The procedure
The patient looks into a very strong light source for about 30 to 120 minutes. The intensity of the illumination is between 2,500 and 10,000 lux. This is roughly equivalent to a sunny spring day and is 5-20 times more intense than average room lighting. If possible, the treatment should be performed in the morning, as the effect is best here. During the therapy, the patient can perform sedentary activities such as reading or eating, but should look directly into the light source approximately every 30-60 seconds. Success can be seen as early as 3-4 days after starting therapy, with a direct dose-response relationship and success increasing with frequency of use. Side effects may occasionally include headache, nausea, irritability or burning eyes. As a rule, an ophthalmologic examination should be performed prior to light therapy to rule out the following conditions:
- Glaucoma – glaucoma (increased intraocular pressure).
- Cataract – cataract (clouding of the lens)
- Retinopathies (diseases of the retina / retina).
- Inflammatory diseases of the eye
Other notes
- According to a study of 122 outpatients aged 19-50 years, light therapy versus sham therapy, alone or combined with an antidepressant (fluoxetine 20 mg/d ), proved to be an “effective and well-tolerated treatment for nonseasonal major depression.” Combination therapy of light and selective serotonin reuptake inhibitor (SSRI) was superior to SSRI therapy alone.
- Light therapy may also help major depression: patients with moderate depression showed a better response rate than with an SSRI. In half of patients, therapy resulted in at least 50% symptom reduction versus 29% in patients with an SSRI. Patients treated with a combined SSRI and light therapy showed the best response rate (76%).
Your benefit
Light therapy against winter depression is a very useful and effective method to maintain or improve well-being and vitality even during the cold season.
