Sure, there are triggers.
My triggers a consequence of living the way I like.
When a demanding, stressful period ends my mood can rise excessively. i do more enjoyable things and feel great. Having much to do at work, coping and making a difference has the same effect.

Of course, this can not last for ever. Maybe the depression is due to exhaustion.
Long periods with plain, ordinary days also makes my mood drop, but seeing exhibitions, avantgarde theatre, or interesting lectures helps a lot.
Maybe my ADHD drives me.

Alltogether, I mostly thrive, but will try to take some more care.