How to Be Happier in January Than in July

“I like these cold, gray winter days. Days like these let you savor a bad mood,” said the comic artist Bill Watterson. But if your sense of humor has gone cold, and nothing—not even a light box—helps, then it’s time to visit a mental-health professional, who may suggest cognitive behavioral therapy (CBT). In the short run, the two traditional therapies (light box and CBT) are equally effective. But when researchers at the University of Vermont tracked patients the following winter, they found that the CBT group was much less likely to relapse than light-box users and even those who used a combo of the two therapies. The explanation: Relapsers over-relied on light boxes, which they stopped using consistently. Only the sufferers who used CBT alone changed their attitude—and that lasts.

Next: 21 ways to blast away the winter blahs