Never heard of her, but some quick excerpts from the wiki in Stern's favor
" Plato began having drug and alcohol problems early in life. At age 14, she overdosed on Valium. She admitted to drinking and using recreational drugs during her years on Diff'rent Strokes."
"She was referred to by one caller as an "ex-con lesbian drug addict with mental problems". This provoked a defiant Plato, as she offered to take a drug test on the air (and even placed a large wager on the results of the test to one particularly doubtful caller). Some callers, however, as well as Stern himself, came to Plato's defense by consoling and complimenting her."
" The next day, Plato and Menchaca were returning to California. The couple stopped at Menchaca's mother's home in Moore, Oklahoma, for a Mother's Day visit. [8] Plato went to lie down inside her recreational vehicle parked outside the house and subsequently died of an overdose of Vanadom (Soma) and Lortab. Although accidental, her death at the age of 34 was eventually ruled a suicide under Oklahoma law."