In an interview with Ed Solomonson “M*A*S*H TV: The Ultimate Guide” Gelbart revealed that despite the series’ huge success, he was in quite poor mental and physical condition. As he told Solomonson:
“Perry Lafferty, vice president of entertainment for CBS on the West Coast and an old friend, said, ‘Every time I saw you during that period,’ because there were frequent meetings at CBS, he said, ‘I thought you were going to die.’ I looked terrible. I was haggard, engaged, obsessed and possessed.
What obsession was Gelbart? If he noticed even a loose thread on one of the actors’ costumes on the set, he walked up to them and bit off the wrong thread (Stanley Kubrick would be proud). Although the series was based on Robert Altman’s brilliant 1970 film (which itself was based on a novel by Richard Hooker), Gelbart considered the series to be “my baby.”
It was at this point that the writer and producer knew he had to leave.