Photo: Thinkstock

I've succumbed to full-blown depression just once, and the only good that came of it was learning that I never wanted to experience anything like it again. So I started collecting little mood-boosting tricks—not cure-alls for clinical depression but small, helpful ways to pull myself back from the edge. After polling friends and colleagues, I discovered that many of them had stumbled upon the same techniques, and they gave me a few new ones, too. Science is beginning to explain why they actually work, which means that these days I don't feel completely ridiculous when I'm in my car and someone catches me belting out a Beatles song.

Trick #1: "I rent a bunch of stand-up comedy DVDs."

The Science: A smile, even a forced one, can improve your mood. In a widely confirmed study, psychologist Fritz Strack, PhD, and his colleagues at the University of Mannheim in Germany had participants view a cartoon while gripping a pen either between their teeth (to simulate a smile) or between puckered lips. The first group found the cartoons funnier, supporting the theory of "facial feedback"—the idea that facial expressions can stimulate emotion. A Fairleigh Dickinson University study showed that laughing brightens mood even more than smiling. (Don't like stand-up? Here are 5 movies that will lift your spirits)

Trick #2: "I go for a run."

The Science: Research has consistently shown that exercise can significantly impact depression and improve overall mood. A 1999 study published in the Archives of Internal Medicine showed that exercise could be as effective as medication. Scientists aren't exactly sure why it works so well: because it relieves stress, acts as a distraction, stimulates production of neurotransmitters (including endorphins—which have painkilling properties and can bring feelings of euphoria—as well as serotonin and dopamine), or all of the above.

Trick #3: "I try to commit acts of kindness."

The Science: Volunteering at a hospital or shelter, tutoring a budding reader, and even donating clothes to Goodwill facilitate a "helper's high." The benefits of altruism are most apparent when there's person-to-person contact. Allan Luks, author of The Healing Power of Doing Good, has found that simply recalling a charitable act brings back the same, albeit less intense, good mood.

Trick #4: "I listen to Madonna, sing loudly, and dance around the living room."

The Science: A number of studies suggest that listening to music stimulates the brain to release endorphins. Recent research at the University of Manchester in England showed that listening to loud music activates a part of the inner ear called the saccule, which is connected to an area of the brain responsible for drives like hunger, sex, and pleasure seeking.

Trick #5: "I buy bright red tulips."

The Science: A 2001 Rutgers University study on the mood-lifting effect of flowers showed that 72 percent of seniors who received one or two bouquets over a six-month period were happier than they had been. In a separate study, flowers evoked a stronger response than other gifts.

Here are five more everyday activities that can make your mood go from bad to good!