Bright light therapy (phototherapy) is known to have a positive and uplifting effect on mood, especially when natural daylight is received in the morning hours.
Bright light therapy (phototherapy) can also be used for this purpose. Although observations regarding this have been known for about a century, it has become a systematic treatment application over the last 20 years.
Devices used for bright light therapy (phototherapy) are now portable and filter out UV light. Research has shown that bright light therapy (phototherapy) has a positive effect on mood, leading to an improvement in depressive symptoms; has a regulatory effect on the circadian rhythm (biological clock); enhances the efficacy of antidepressant medications; and regulates sleep quality.
How Does Bright Light Therapy (Phototherapy) Work?
It has been determined that its efficacy, particularly in seasonal depression, may be related to its impact on biological rhythms and may manifest through monoaminergic and melatonergic mechanisms. In major depression, changes occur in the circadian rhythm (biological clock). This mostly takes the form of a phase delay. Clinical and epidemiological studies have revealed that the frequency of depression is higher in individuals with a phase delay. This phase shift in depression is also held responsible for certain depressive symptoms.
Melatonin is a neuroendocrine substance that plays a important role in the circadian rhythm. Its secretion increases at night and in the dark, and decreases during the day and in the light. Melatonin is a hormone that can lead to depression. The suppression of melatonin secretion by bright light leads to an antidepressant effect.
How is Phototherapy Administered?
Bright light therapy (phototherapy) is administered, particularly in the early morning hours, either at 10,000 lux for half an hour or at 2,500 lux for 2 hours. Applications and research conducted have shown that treatment efficacy is higher at these doses and durations. The duration of application is 1 week. During the application process, the person does not look directly at the light source and sits sideways. There should be a distance of at least 1 meter between the device and the individual.
Are There Any Side Effects of Phototherapy?
It has no serious side effects. However, it has been reported that when used at high doses and durations in mood disorder patients, it may cause manic switches.
It has been suggested that bright light therapy (phototherapy) can rarely cause nausea and headaches depending on an increased dose or prolonged duration. No toxic effects on the eyes have been demonstrated. What is important for all these side effects is conscious and controlled use at appropriate doses and durations.
In Which Conditions Can It Be Used?
Bright light therapy (phototherapy) is used in combination with pharmacotherapy for seasonal affective disorders. It initially began to be used especially in cases of depression occurring seasonally; later, it was observed to be effective in non-seasonal depression cases as well. Furthermore, phototherapy can be successfully applied in chronic fatigue syndrome, sleep disorders experienced due to changing shift hours or jet lag, and in pregnant women where pharmacological treatment cannot be administered.
