Complex sentence: Schrader recalls that shooting the film was difficult, because of the artistic and personal tension among him and the actors; it was the only occasion he suffered an on-set mental collapse and made him seriously reconsider his career.
Split into simpler sentences: Schrader recalls that shooting the film was difficult, because of the artistic and personal tension among him and the actors. Schrader said that was the only occasion he suffered an on-set mental collapse; it made him seriously reconsider his career.