Light Therapy or Talk Therapy for SAD

It's that time of year again in the northern hemisphere - talk about seasonal affective disorder, or SAD.

What is SAD? Much of how we feel comes from the amount of daylight we experience, experts believe. So in the fall, as daylight hours shorten and night hours are longer, we see less sunlight. Some people go to work in the dark and come home in the dark. There may be days when they only see sunlight through their office window - if they have one. It's believed that in some people, this lack of sunlight causes SAD. And one remedy for this is to use light therapy - exposure to special lights of specific wavelengths to combat the lack of natural light.

SAD lights are commercially available in various shapes and forms, from large standing ones to portable folding ones, usually promoted as great for travel or to bring to your office. But do they work? A new (small) study published today in the American Journal of Psychiatry shows that while the lights may be helpful, they may not be as effective over the long-term in battling SAD as "talk therapy," or cognitive behavioral therapy (CBT).

The light therapy works, the researchers agree, but the problem behind using light therapy is the need for continuous use for it to be effective. Users need to use the light every day for a set number of minutes per day, and if they stop, their SAD symptoms reappear or worsen. The researchers also point out that there can be problems with ensuring that the light therapy is always available. People may not be able to purchase portable units or be in environments where they can use lights. Talk therapy, on the other hand, doesn't require special equipment or adaptation.

The study looked at 177 people with SAD over the course of two winters. The group was  divided into light therapy and CBT subgroups. By the end of the second winter, more people who used light therapy experienced a return of their SAD symptoms than did those who used CBT. But, only 30% of the light therapy group were still using their lights that second winter.

"Light therapy is a palliative treatment, like blood pressure medication, that requires you to keep using the treatment for it to be effective," lead author Kelly Rohan said in a news release. "Adhering to the light therapy prescription upon waking for 30 minutes to an hour every day for up to five months in dark states can be burdensome," she said. 

Light therapy does work for many people, but it must be used consistently. If that isn't possible, perhaps CBT is the better option.