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—small, helpful ways to pull myself back from the edge. Science is beginning to explain why they actually work, which means that these days I don't feel ridiculous when I'm in my car and someone catches me belting out a Beatles song.

Find out the science behind these mood-boosting tricks!

You rent a bunch of stand-up comedy DVDs.
A smile can improve your mood. In one study, participants view a cartoon while simulating a smile or between puckered lips. The first group found the cartoons funnier.

You go for a run.
Research shows that exercise can significantly improve mood. Scientists aren't exactly sure why it works so well: because it relieves stress, acts as a distraction, stimulates production of neurotransmitters, or all of the above.

You try to commit acts of kindness.
Volunteering can facilitate a "helper's high." The benefits of altruism are most apparent when there's person-to-person contact.

You listen to Madonna, sing loudly, and dance around the living room.
A number of studies suggest that listening to music stimulates the brain. Recent research showed that listening to loud music activates the inner ear, which is connected to an area of the brain responsible for drives like hunger, sex, and pleasure seeking.

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

Here's the science behind five more mood-boosting tricks!

You buy bright red tulips.
A 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.

You hang out with friends.
Numerous studies have documented the benefits of social support. According to one study, even more important than social support is a sense of belonging.

You snuggle the dog.
Two studies showed that both AIDS patients and senior citizens benefit from having pets. An earlier study showed that pet owners were also at decreased risk of heart disease.

You find a patch of sunlight, curl up, and fall asleep.
A common cause of depression is seasonal affective disorder (SAD), in which lack of sunlight affects sleep patterns and mood. Some therapists believe that even people not affected by SAD can reap the rewards of sunshine.

You change the landscape.
Perhaps it's the calming properties of the ocean or a starry sky. A good number of people mentioned that a change of scenery is an instant head clearer.

Return to the first four ways to keep yourself from going over that edge.