What is the difference between Multiple Personality Disorder and Bipolar Disorder?

Bipolar Disorder used to be called Manic Depression, it is when an individual cycles between depression and mania, sometimes hastily. Multiple Personality Disorder is now called something else, but it is when something tragic happen to someone when they were young (usually) and their personality branched off into other personalities to cope, it's a coping works. Usually the original personality have no idea the others exist without a great deal of therapy and they lose track of time, sometimes days because the other personalities are within control. It's a very interesting but scary infection.
Hope this helps.
Bipolar disorder is a chronic mood disorder characterized by episodes of depression ( depressed mood, loss of interest, sleep/appetite problems, feelings of guilt/worthlessness, loss of perkiness and concentration, suicidal ideation) and hypomania or mania (increased energy, elevated or irritable mood, increased talkativeness, race thoughts, grandiosity, psychomotor agitation, decreased need for sleep, increased objective directed behavior, increased libido, distractibility, impulsivity). There is also an mood state called mixed which is a combo of manic and depressed all at once. The moods (depressed, hypomanic, manic) are clearly different than the person's middle-of-the-road mood. Bipolar disorder is often thought to have a genetic component since it tend to run in families. There are a few medications on the market to treat it.

Multiple self-image disorder, now called dissociative identity disorder, is a dissociative disorder. Dissociation is when you quality as though you are somehow disconnected from or outside of yourself. There is debate in the medical community as to whether this is really an illness or not but it is definitely very different from bipolar disorder which is well standard and studied. Individuals with dissociative disorder come from backgrounds where on earth there has be significant trauma such as prolonged neglect or physical/sexual abuse. The dissociation become a way of adapting to the abuse-the personage protects themselves by going away from the situation in their mind. People with this bad health report to have different "personalities", all of whom are distinctly different, usually chitchat and write differently and who are generally unaware of the other personality. The exception being the dominant personality which is aware of adjectives the others. Think of it like a jail steward. The warden can see all of the prisoners within their cells and the prisoners can see the warden but they can't see the other prisoners. Multiple sense of self disorder is generally treated with long possession psychotherapy-medications are only helpful if near is a co-morbid mood or anxiety disorder.
Answers:    Multiple Personality Disorder (henceforth I shall call it MPD) is a disorder which is typified by sufferers having several distinct personality in their psyche. Let's say there's a man name Howard, and he's generally a nice guy. Perhaps Howard had some harm in his past, and have difficulty expressing defiance towards male authority data.

If Howard is unfortunate enough to suffer MPD, this frustration might manifast contained by a second personality. This personality might be call Stuart. Stuart is the precipitate of what Howard feels he can't be - when challenged by manly authority figures, he arcs up and is easilly angered, defiant and equipped to defend himself. Howard might be aware of Stuart's presense in his mind - he may even be capable of control when Stuart has control. Thus when Howard is confronted by a surly stranger at a bar, he may unleash Stuart as a munificent of defender.

Bipolar is remarkably more common and far smaller quantity obvious. It's typified by wild, unpredictable moodswings of a severity unreasonable for a situation. If Howard suffered Bipolar instead of MPD, he might become extraordinarily angry at quite a slight provocation. In all cases, he remains howard - but he flits from extreme to extreme. From content, to angry - from angry, to miserable. Bipolar may be more adjectives, but it's no cakewalk of its own.

Hope this helped.
its no longer called multiple self-worth disorder - its now called dissociative disorder- this is when a party have multiple "persons" "taking" over they lose time when these other "people" take them over and can do strange things.
bipolar is when someone have days of being down in the dumps and next next week they are so happy and hyper its annoying and uncontrollable- its leading mood swings and its moods for days