It’s a chicken and egg thing. When I’m up, I write. When I’m coming up out of a down swing, I start to write. When I swing back down, all writing stops. I don’t know if writing is a symptom or a cause of an improvement in my mood, but I know I can only do it when I’m up, and the longer I do it, the longer I’ll stay up.
Problem is, the longer I stay up, the deeper my next down might be when it comes around. For me, it’s writing, but I’m pretty sure for other people, the same can be applied to all kinds of pursuits, be they artistic or not.
I’m probably not alone in this sort of thing. If someone you know has mood swings, and a noticable tell – meaning you can spot a trigger or pattern of symptoms/causes that alerts you to them – don’t be afraid to let them know. It took me years to realise the two were related for me, and much trouble could have been avoided had I known.