Light therapy and antidepressants are most commonly used treatment options for managing seasonal affective disorder (winter blues or winter depression). Light therapy is preferred at the beginning of the treatment, but it is not always fully effective, so antidepressants need to be introduced. Antidepressants include wide range of drugs that change the concentration of certain neurotransmitters (substances that allow the communication between nerve cells) in the brain tissue.

Light therapy involves the exposure to light of specific wave-length for certain amount of time during the day. The effectiveness of light therapy is confirmed not only in the praxis, but also in many studies, and it is considered first line therapy for SAD. Light therapy lowers the levels of stress hormones such as cortisol, and increases the level of melatonin, which is very important for day-night cycle regulation. Antidepressants on the other hand, have not yet been very extensively studied for the treatment of SAD, but there are evidences that they are very beneficial, especially the group of antidepressants called Selective Serotonin Reuptake Inhibitors (SSRIs).

Many studies have been conducted in order to compare the effectiveness of light therapy and antidepressants in the treatment of seasonal affective disorder. The recent study conducted in Mood Disorders Centre, UBC Hospital in Vancouver, compared the effectiveness of light therapy and fluoxetine (one of the most commonly used antidepressants) in beating winter blues. They divided patients with SAD in two groups, one of which received fluoxetine, while the other received light therapy for 8 weeks. It was concluded that outcomes were very similar, and both methods were almost equally effective. Still, it was not investigated whether the patients who were unresponsive to one treatment would get benefit from another.

When it comes to side effects, the light therapy seems to be having an advantage. The side effects of light therapy are usually rare and benign, and they go away after getting used to the treatment. They include eyestrain, headache, and nausea. Light therapy is not approved from Food and Drug Agency (FDA) for the treatment of SAD, although it is approved for acne and joint pain relief. FDA still has concerns about the effectiveness and safety of light therapy. Antidepressants are drugs that affect the levels of neurotransmitters in the brain, so the side effects need to be considered, but they are very rarely serious, especially with new generation drugs. Antidepressants can cause nausea, vomiting, decreased sex drive, diarrhea, constipation and headache.

Important questions about the treatment of SAD still need to be answered. For example, the effectiveness of light therapy is investigated only in short term studies, so the benefit of longer treatment is still not entirely proven. Also, the studies conducted so far did not include patients with very severe depressive symptoms.

In summary, both treatments have their advantages and drawbacks. Some patients seem to have poor response to one therapy approach, but receive much more benefit from another. In some cases, both antidepressants and light therapy are needed, with additional help of psychotherapy. SAD treatment should be planned for every person individually in order to reach best possible outcomes.


Lam, R.W., Levitt, A.J., Levitan, R.D., Enns, M.W., Morehouse, R., Michalak, E.E., Tam, E.M. (2006). The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. Am J Psychiatry. 163(5):805-12.

Prasko, J., Brunovsky, M., Latalova, K., Grambal, A., Raszka, M., Vyskocilova, J., Zavesicka, L. (2010). Augmentation of antidepressants with bright light therapy in patients with comorbid depression and borderline personality disorder. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 154(4):355-61.

Roecklein, K.A., Rohan, K.J. (2005). Seasonal affective disorder: an overview and update. Psychiatry (Edgmont). 2(1):20-6.