Light therapy is a non-pharmacological treatment that is best studied for seasonal affective disorder (SAD) but has also been found to be useful in other depressive disorders. It can be tried as the primary treatment for mild depression or for antepartum or postpartum depression and as an adjunctive treatment for moderate-severe depression. It has been found to be particularly helpful for these symptoms: early morning fatigue, poor motivation to start the day, and difficulty waking up. Evening light therapy can be helpful for sleep maintenance problems. Some people describe seeing results in a few days, and for others it can take a couple weeks.
The idea of light therapy is that the person spends a designated amount of time in front of a light box, which mimics natural light. However, there is no identified standard of care for which light wavelengths are maximally safe and effective, which method of light delivery is optimal and how long it should be delivered. Some of these parameters are better delineated for SAD but not for general depression. These are questions that should be studied in more detail to establish a standard of practice to make it a more effective treatment approach. What is known is that it is important to be consistent on a daily basis with the light therapy schedule and that light from the therapy box should enter the eyes indirectly.
Light therapy is a relatively safe treatment approach. Patients with photosensitivity (from medications or other causes) or certain pre-existing medical conditions of the eyes and skin (macular degeneration, porphyria, lupus erythematodes, to name some) should consult with their specialist providers before considering light therapy. Possible side effects include: eyestrain, headache, and nausea. More serious side effects include irritability,
agitation or euphoria associated with bipolar disorder; it is thought this occurs because the treatment “flipped” the patient into a manic state. If a milder side effect occurs, it may go away on its own within a few days. Alternatively, the patient could try reducing the treatment time, moving farther from the light box, taking breaks during long sessions or changing the time of day the light therapy is used. For a more serious side effect, it would be important to discontinue the treatment and re-evaluate the patient’s diagnosis and treatment plan.
Light therapy boxes should be designed to filter out harmful ultraviolet (UV) light, because UV light can be damaging to the eyes and skin. Therefore it is important that the patient be instructed to look for light therapy boxes that emit as little UV light as possible.
A prescription is not needed for a light therapy box, but unfortunately it also means that the cost is rarely covered by health insurance. It does not hurt to try to advocate for your patient for the insurance to cover the cost, if you think it could be a helpful treatment.
In summary, light therapy should be considering as a treatment recommendation for certain patients who are presenting with depression, either as a monotherapy or as an adjunctive treatment. It is a relatively safe and easy-to-use treatment approach. It is hopeful that this article has increased your knowledge on this treatment approach.