My assumption is that it's a momentum issue. I mean, as I understand it, being bipolar is
already a momentum issue, where a person's mood is like one of those
pirate ship rides at the fair, where the bipolar person habitually builds up enough momentum
without recognizing it* that they smash up against
the stays at either extreme, which leads to...problems.
I mean, I'm no DSM dude, so feel free to stomp the above if it's incorrect.
--Patrick
*This being the part that classes a person as "bipolar"