"My first reaction to it was to start drinking heavily," he told Stern. "I used to drink to party, but then I was drinking alone. Every day."
Fox said after the drinking, came about a year of what he calls "a knife fight in a closet."
The 52-year-old actor explained that he began seeing a therapist, and his life started to get better and his marriage got stronger.
"The Michael J. Fox Show," inspired by Fox's life, focuses on the character Mike Henry (Fox), who returns to his career as a news anchor after taking a hiatus because of his struggle with Parkinson's.
The show debuts Thursday at 6 p.m. PST on NBC.