Over the years, I have witnessed a significant increase in the diagnosis of "Bipolar Disorder" (formerly called "manic-depressive" illness) in people who have an antisocial personality disorder. What I believe has happened is that well-intentioned professionals who do not regularly evaluate or treat antisocial individuals are deceived.
The antisocial person thinks in extremes. He is number one or he is a zero. There is no middle ground. He has highly unrealistic expectations of himself and others. As long as he can prop up a shaky image of himself as a powerful and unique person, he conceives of himself as on top of the world. He appears to fulfull criteria of a "manic episode" specified in the American Psychiatric Association's Diagnostic and Statistical Manual (TR-4) such as "inflated self-esteem and grandiosity," "increase in goal-directed activity," and "excessive involvement in pleasurable activities that have a high potential for painful consequences" (e.g., unrestrained buying, sexual indiscretions, foolish business investments). Inevitably, events in life do not fulfill his unrealistic expectations. And so his unrealistic view of himself and of the world is threatened. Then he may appear to experience a "major depressive episode" (another aspect of a bipolar disorder). However, he is unlikely to remain depressed for long, if at all. For the antisocial person, the "best" antidote to the collapse of one's plans and to feeling like a nothing is to demonstrate that you are somebody -- thus further assertions of his power and control, often through the commission of crimes.
The antisocial person's peaks and swamps of emotion thus are very different from a person who suffers from a mood disorder and who may genuinely merit the diagnosis of a "bipolar disorder". There is no medication that effectively treats and alters the antisocial person's cognitive processes.