that's kind of a difficult one b/c someone can be seriously depressed for a long time and you not see the manic...or when you see the manic you might not recognize it.
here is some info that you might wish to scan through and see if any of it answers any of your questions:
LOTS of information for friends and family of the bipolar
http://www.soberrecovery.com/forums/...-bipolars.html