The world seemed to come crashing down on June 20, 1993, for then 36-year-old "Bart" of Queens, New York. Before that day, he had college degrees from Dartmouth and Harvard, and was earning $135,000 a year in business. His wife was a New York psychologist.

But afterwards? "That day, I was talking on the phone to a colleague about future technologies," said now 52-year-old Bart in a telephone interview. (His name has been changed.) "During the call, I had what felt similar to a panic attack and felt this rush of heat all over my body. By the time I'd hung up, I was shaking. I was completely freaked out."

At home, his psychologist wife had no explanation. By Monday, he had experienced an amazing cognitive shift. The depression and anxiety he felt would last months. The next year, during a more severe bout, he was hospitalized and underwent shock therapy.

He said, "In the next seven years, I spent about two years total in a normal state, three years depressed, and eighteen months manic. I quit some good jobs I shouldn't have quit because I didn't have a plan for what to do next."

His manic periods would last about nine months before ending in depression, he said. The depressive periods would last months or years. In May 2000, a psychiatrist diagnosed him with a form of bipolar disorder, which is a brain disorder causing unusual, severe shifts in activity levels, mood, energy, and the ability to complete everyday tasks.

He spent the year 2000 in depression and was becoming suicidal. Then from 2002-07, he began another "normal" stretch. "Now over the last three years, I've had some very bad days with depression," he said. "I've also had fine days, but no manic days."

Though his personal income fell to $8,000 last year, he still sees bright spots. For one, his marriage of 27 years has held up well. He has more empathy towards people with mental illness. And he continues working best he can. He tells people with bipolar disorder to exercise, sleep regularly, eat well, and take their medication.

Yet, some days he struggles. "People think it will never happen to them," he said. "I had a whole different life planned. I always thought how lucky I'd been and couldn't imagine wanting to trade places with anyone. It was quite the turnaround."