I've got a buddy that is bipolar, mildly psychotic or something. He's very difficult at times, although I seem to get along with him better than most. He also has delusional thinking where he doesn't seem to interpret a real experience like most everybody else does. I am also convinced he also experiences delusions (unreal experiences) from time to time.
What would be some defining characteristics to look for to distinguish between whether he is bipolar, manic depressive or having psychotic episodes?
Most of the time he's pretty much OK, except he is consistent in the details of his delusional thinking and experiences.
You've pretty much described it. Manic depression is the old name for bipolar - they have just discovered there are several different kinds. (Believe it or not, Charles Krauthammer is the "discoverer" of a few of these - that was his profession before he became a commentator.
It's a mood disorder. The classic picture of elation followed by depression really isn't accurate for everyone. That's the classic "manic depression".
Basically the big thing to look for is a mood out of control, out of the norm. It can be anything, depression, anger, but most often some kind of agitation. It is often kicked off by stress but people are often fooled into thinking that if only the person wasn't stressed the mood wouldn't happen. But it would, because anything can be the stress, from someone wearing the wrong clothes to an advertisement in the newspaper -and they will tell you it's YOUR fault.
When the mood kicks off, the logic disappears, sometimes to the point of delusion. They can get totally irrational. It's like talking to or arguing with a wall. Some can get very abusive and very angry, and consequences is not a word that translates for them at all. They can throw things, scream, and curse a blue streak, which is weird because they can be the nicest people when not cycling.
People rarely realize it's mental illness. They just consider them to have an anger problem, or be difficult. But the mood is out of their control, and then usually cycles into depression at a later date.
They sometimes have drug or drinking problems, and can be extremely creative, artistic and intelligent. Think Carrie Fischer. All of the ones I know with a good case have ended up with legal problems, because they will just do whatever their mood tells them to. They just DO things.
I have known a few to go on spending binges. They usually think YOU are the crazy one. The sad thing is, they really need good friends to help them over the hard times, yet often lose their families and friends because they are just so darn tough to be around. Many lose their children. It's a terrible illness if they have a bad case difficult to control. People don't understand it.