Before I was diagnosed and on mood stabilizers I had WAY more depression than manic episodes. Intense mania lasted anywhere from twenty minutes to three days. Although I was on Remeron to manage anxiety and insomnia so that might have helped keep the episodes somewhat in check.

I wasn't strictly always either up or down, sometimes I was just stressed out and anxious. I've known people who have episodes that last months. I've had multiple episodes in an hour or at a time.

The exact cycling isn't as significant as the reality that there is a noticeable pattern of behavior.