Disclaimer that I don't know much about anything so you shouldn't take my word:

My understanding is that mania and hypomania have roughly the same effect as a mild concussion - you lose some of your cognitive skills for awhile. A mild concussion takes 2-3 months to heal, but the damage from mania takes a couple of years - assuming no further episodes, no further damage during that time.

Depression doesn't seem to have the same effect.

Frankly, this scares the day lights out of me, which is why I want to get a lot more serious about preventing hypomania.

This is accurate to the best of my knowledge BUT I was a liberal arts major and could have it all wrong.