For years, all Lynn Bryan Johnson saw in the mirror was a big, fat loser-a sad, angry, self-loathing waste of a person. She walked with her head lowered, unable to deal with being alive.

Johnson lives with bipolar disorder, a frequently misunderstood mental illness characterized by episodic depression and mania. The disease contributed, at least in part, to her alcoholism. When depressed, she feels suicidal. When caught in the grip of mania, she experiences intense rages, or a state of self-destructive euphoria.

In Fat, Drunk, and Bipolar, Johnson invites readers to...