Spring. As the sun is out more and more and it gets warmer and brighter, I have a tendency to get depressed. A lot of people get winter depression, I'm the opposite.

major life changes, positive or negative. A move to a new house or apartment, starting a new job, quitting an old one, ending a relationship on bad or good terms, etc.

Sometimes just because.

My depressive episodes tend to last a minimum of 3 months though. They tend to be long. I've had one last a year.

Also, sleep changes. I don't know if that's a trigger or a result though... same with hypomania. hmph.