The connection between chocolate and depression in real life:

“I’ve had mild, pervasive depression for two weeks, but since science says this 85% dark chocolate bar can raise my serotonin, I’m waiting for a barely perceptible lightening of my mood.”

The connection between chocolate and depression in Harry Potter:

“A dementor gave me depression so hard my soul almost ripped out of my body, but I ate a chocolate bar that’s been sitting in this guy’s jacket, and now I’m a thousand times better.”