What Really Killed the Cat?

Was it curiosity? ...or could it have been depression?

I wonder: do cats get depressed? Maybe that's why cats eat and sleep so much, and get all hissy and snarly one minute but then rub up against your ankle and mew the next. It would also explain why many the feline end up on suicidal quests to sate their curiosity. If you're bored, lonely, and down enough, you'll gladly do things like crawl under the car and fall asleep, jump into the dryer because it's a warm new place to lie down, nibble at the roach poison to see what it tastes like...