Kelly Rohan, a psychologist at the University of Vermont, has become the first person to publish a study of the long-term effects of various cures for SAD.
The research appears in the September issue of the journal Behavior Therapy.
In the first year, Rohan randomized 69 people suffering with SAD into one of four groups viz. light therapy treatment, cognitive behavior therapy, a combination of the two or a wait-list control.
After a year she reviewed the progress of the patients.
She found only 7 percent of those who had received CBT had a recurrence of SAD compared to 36.7 percent of people given light therapies.
Of those receiving a mix of the two therapies the recurrence rate was only 5.5 percent.
Rohan also found that even in cases where SAD had resurfaced in patients after taking CBT, its severity was much less.
An earlier study had shown combination therapy to be more effective, but Rohan says this was because constant monitoring ensured the participants followed the therapies regularly, which is almost never the case when they are left on their own. Her study even shows that people rarely follow therapies regularly over the long-term.
She said: "People treated with only CBT - that's all they know... so I think they do it with gusto in the next year and reap the benefits."
And added: "The combination therapy may blow your socks off across six weeks of the initial winter.... but if it doesn't have good long-term outcomes, what is the point? This is a recurrent depression. It's going to come back every year in some form and I want to develop treatments that are going to have lasting effects."