I'm usually in depressive episodes but my manic ones are very chaotic.

My manic episodes include partying a lot (I once partied for 6 months straight, every day), drinking and smoking more frequently, my anxiety basically disappears, I feel like the energizer bunny cause I'm just going and going, I start getting really irritated with people and will lash out too, getting into fights (rare but it has happened), doing things I wouldn't normally do (sex w/ strangers, shopping sprees) but then I crash into my depressive episode after a while and all that energy goes away and I'll rarely leave my bed during these times. I won't eat, I'll sleep a lot, and I feel very empty.

As far as triggers go
- stress
- lack of sleep
- arguments with family/friends
- breakups
- not excelling at work/school will make me very depressed
- like all74 said, it can just happen sometimes

I hope this helps!