You have probably heard about seasonal affective disorder (SAD), a depressive condition that some people feel when it turns gray outside for extended periods. A treatment called bright light therapy, which is pretty much what it sounds like — you put a bright light box in your house — often helps diminish the effects of SAD. But can it treat non-seasonal Major Depressive Disorder, a far more serious condition than SAD with a much higher risk for suicide?
A team of scientists led by Dr. Ritsaert Lieverse of an Amsterdam psychiatric institution with a very Dutch name — GGZ inGeest — recently completed a four-and-a-half year study, the first of its kind, to investigate that question. Previous research had shown that bright light treatment (BLT) targets neurotransmitters such as serotonin and dopamine that are associated with depression, so they figured the treatment could significantly reduce even major depressive symptoms.
The study, which was published Jan. 3 in the prestigious Archives of General Psychiatry, looked at a population that gets outside less often — the elderly — and that also can’t see as much light as those with younger eyes. They randomized 89 MDD patients who were at least 60 years old into one of two conditions: 42 got a bright blue light to take home, and 47 got a dim red light. Neither group — nor any of the staff actually handing out the light boxes — knew the purpose of the devices. The participants were instructed to use them for an hour each morning for three weeks.
The results were indisputable: more than half — 58% — of the patients who completed the experiment reported fewer depressive symptoms; only 34% of the placebo group did. These may not sound like huge numbers, but consider that all these patients have a highly difficult-to-treat illness; if untreated, nearly 17% of those with MDD kill themselves, according to a 2005 study. Many others end up hospitalized, sometimes for years. The results show that BLT works to improve their lives about as well as — and in some cases better than — antidepressant drugs. And BLT carries few, if any, side effects.
The Dutch team’s results held up even when they controlled for whether and how often the participants had used antidepressants, how old they were, what their gender was, and when their depression first began.
How, exactly, is the bright-light therapy working? For one thing, it somehow reduces cortisol, a hormone heavily implicated in stress. For reasons that aren’t quite clear, it also helped participants sleep better: they woke up a little earlier and didn’t stay in bed as long. (Depressed people often wake up late and then simply lie in bed.)
No one knows if BLT could work in the long term, since this study was so short, just the three weeks. But now even those with a serious mental illness may be able to experience the bliss you feel on a sunny day at the beach, even if just for a while.