Psyblog reports on a study that showed positive memories can help overcome depression...at least if you're a mouse.
Yes, this study was conducted with mice. They gave male mice a positive experience--exposure to a female mouse. They were able to locate this experience in the brain so they could access it again later.
Next, the mice were given a stressful experience that put them into a depression-like state. The article doesn't say exactly what this was. Maybe a researcher read them the news headlines.
Then they used light to stimulate the part of the brain that held the positive memory of the female mouse. The male mice quickly recovered from their depression.
Knowing how the male brain works, this didn't surprise me all that much. I wonder whether it would work as well with female mice who are exposed to a handsome male mouse.
When I felt a bit down, I decided to give it a try. My first attempt failed because exposing myself to a female mouse didn't make me happy and it seemed to frighten the mouse. Then I realized I already had happy memories, none involving rodents, I could call upon.
I think this is a bit more complicated in humans than in mice. For instance, remembering a happy time with another person can come attached with all kinds of negative thoughts as well, particularly if you're already in a down mood.
Thoughts like, "Yes, that was a happy time, but she's not in my life anymore!" or "Yes, but stupid me, I should have appreciated him at the time," or "Yes, we had a great time on that vacation, but now I don't have enough money to do that kind of thing," etc.
The positive memory would have to be unencumbered by any of those kinds of additions. A depressed person is really good at finding the "yes, but" view.
My non-scientific conclusion is that this could work when you're feeling slightly down in the dumps, but could actually backfire if you're seriously depressed. (If you are, please get some help. You may think your view of reality is accurate but when you're depressed you're seeing things through a deceptive filter.)