Kristy McNichol diagnosed with bipolar disorder

Kristy McNichol diagnosed with bipolar disorder, Born on September 11, 1962, the daughter of an actress, Kristy appeared in her first commercial at 6 and worked steadily, mostly in television, where she won two Emmy awards for her role in Family, also starring Sada Thompson and Meredith Baxter, which ran from 1976 to 1980. She turned to films then, with a few successes, including Little Darlings with Tatum O'Neal, and some lesser successful films like The Night the Lights Went Out in Georgia with Dennis Quaid. Her confidence was shaken
by the flop of one, The Pirate Movie, and having a (mistakenly) controversial plot in another, White Dog, prevent the film from release in the United States.
At age 23, Kristy did not return to France during a break in filming Just the Way You Are. Drug abuse rumors were rampant, but in fact she'd had a breakdown. Some sources say this was when she was diagnosed with bipolar disorder. She did eventually finish the film, but her career languished in "forgettable" films until 1988, when she had a starring role in the popular television series Empty Nest. The series ran for 7 years, but she left in 1993 as Kristy's depression reportedly became too severe for her to continue (other sources say she was diagnosed with bipolar at this time). She returned for a few episodes at the end of the series.
Working very little after that, Kristy McNichol finally retired from acting in the late 1990s. Her last reported statement to the public was in 2001:

"A lot of people have wondered what I've been up to. I retired from my career after 24 years. My feeling was that it was time to play my biggest part - MYSELF! I must say that it has been the best thing that ever happened to me. So many fans are disappointed that I'm not currently acting, however some may not realize that the process I'm in at this time is necessary and vital for my personal happiness and well-being." I remember Kristy McNichol when she - and I - were young. Although the TV series Apple's Way didn't last long, I found it wonderful and watched every episode. Kristy, then 12 years old, was impressive and engaging. In the next two years she played three different characters in episodes of another personal favorite of mine, Starsky and Hutch. Again she impressed me enough that I still associate her with the show today.

Source : http://bipolar.about.com/od/actorsandactresses/a/kristy-mcnichol-bipolar-disorder.htm