The story was partially autobiographical for Paul Schrader, who suffered a nervous breakdown while living in Los Angeles. He was fired from the AFI, basically friendless, in the midst of a divorce and was rejected by a girlfriend. Squatting in his ex-girlfriend's apartment while she was away for a couple of months, Schrader literally didn't talk to anyone for many weeks, went to porno theaters and developed an obsession with guns. Schrader was working at the time as delivery man for a chain of chicken restaurants. Spending long days alone in his car, he felt--I might as well be a taxi driver. He also shared with Bickle the sense of isolation from being a mid-Westerner in an urban center. Schrader decided to switch the action to New York City only because taxi drivers are far more common there. Schrader's script clicked with both Martin Scorsese and Robert De Niro when they read it.