CBT Beats Light Therapy for Seasonal Depression

Cognitive therapy was aimed at 'getting people out of hibernation mode.'

Individuals with seasonal affective disorder (SAD) who participated in 6 weeks of daily cognitive-behavioral therapy (CBT) saw more improvement than those who used light therapy, with the advantage for CBT becoming apparent two winters post-intervention, researchers reported in AJP In Advance.

Two winters after receiving either CBT or light therapy, researchers found that those who received CBT experienced a smaller proportion of recurrence as measured the SIGH-SAD, a primary measure of SAD symptoms, as compared with those who received the light therapy (27.3 percent versus 45.6 percent, respectively), and larger proportion of remissions from SAD as defined by a score of  less then 8 on the Beck Depression Inventory-II (68.3 percent  versus 44.5 percent, respectively), according to Kelly Rohan, PhD, and colleagues from the University of Vermont.

For the study, Rohan and colleagues randomized 177 patients to receive either light therapy on a daily basis for 30 minutes upon waking or to receive CBT-SAD, a type of intervention that delivered psychoeducation, behavioral activation, and cognitive restructuring specifically targeting winter depression symptoms in group therapy sessions twice per week for 6 weeks.

Rohan told MedPage Today that CBT-SAD therapy involved "getting people out of hibernation mode so they approach rather than avoid winter... the activities do not necessarily need to be outdoors or involve communing with snow. They involve anything the person finds enjoyable that can be done in the winter to experience pleasure, rather than withdrawing and socially isolating oneself, which breeds depression." This could involve staying active in one's routines, such as going to the gym, maintaining hobbies, or developing new hobbies to take the place of summer-specific hobbies, or seeing people socially, for instance.

The following winter, researchers contacted study participants in both groups, asking them to resume the treatment they received during the previous winter under their own volition.

Those who received light therapy the previous winter received a letter asking them to resume the daily light therapy upon the onset of the first depressive symptom and those who received CBT-SAD were encouraged to use the skills taught to them the previous winter. Researchers instructed participants in both groups that if recommended strategies were insufficient to relieve symptoms of depression, they should pursue formal treatment, and included contact information for local mental health centers.

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Researchers conducted in-person visits in January or February of the first winter following the initial intervention as well as the second winter.

Responses to CBT the first winter after the intervention strongly predicted its effectiveness the following winter. Those who were depression-free the first winter following the intervention were markedly more likely to be depression-free during the second winter compared with those had still shown depression symptoms during the first winter.

In contrast, those who received light therapy who remained depression-free the winter following the intervention were only twice as likely to avoid recurrence during the second winter compared with those without a substantial initial response.

Light therapy has long been used as a treatment for SAD, but one major obstacle to success in treatment includes lack of compliance. In the study, only about a third of subjects reported continuing light therapy at each follow-up, which may have been in part due to study design, according to the authors.

Said Rohan, "In practice, these data indicate that there are options for treating SAD. If someone is willing not only to use light therapy to alleviate current symptoms, but also to keep using daily light therapy until spring and resume using it each fall/winter season, that is a viable option -- however, if someone is willing to work on their thoughts and behaviors in CBT-SAD over 12 sessions in a winter, that is also an option. Better yet, CBT-SAD is a treatment that might have longer-lasting benefits than light therapy in terms of lower risk for SAD recurrence and less severe symptoms two winters later."

Rohan said she hopes to get rates of depression recurrence even lower following SAD treatment in her next study. "This may involve early fall booster sessions to reinforce use of CBT-SAD skills as the seasons change," she noted, or for those who receive light therapy, a conversation regarding increasing compliance with the daily regimen to offset depression recurrence.