threatened to quit if his employer did not publish it. While completing the novel, Rand was prescribed the amphetamine Benzedrine to fight fatigue. The drug helped her to work long hours to meet her deadline for delivering the novel, but afterwards she was so exhausted that her doctor ordered two weeks' rest. Her use of the drug for approximately three decades may have contributed to mood swings and outbursts described by some of her later associates. The success of The Fountainhead brought Rand fame and financial security. In 1943, she sold the film rights to Warner Bros. and returned to Hollywood to write the screenplay. Producer Hal B. Wallis hired her afterwards as a screenwriter and script-doctor. Her work for him included the screenplays for Love Letters and You Came Along. Her contract with Wallis also allowed time for other projects, including a never-completed nonfiction treatment of her philosophy to be called The Moral Basis of Individualism. While working in Hollywood, Rand became involved with the anti-Communist Motion Picture Alliance for the Preservation of American Ideals and wrote articles on the group's behalf. She also joined the anti-Communist American Writers Association. In 1947, during the Second Red Scare, Rand testified as a "friendly witness" before the United States House Un-American Activities Committee that the 1944 film Song of Russia grossly misrepresented conditions in the Soviet Union, portraying life there as much better and happier than it was. She also wanted to criticize the lauded 1946 film The Best Years of Our Lives for what she interpreted as its negative presentation of the business world, but was not allowed to do so. When asked after the hearings about her feelings on the investigations' effectiveness, Rand described the process as "futile". After several delays, the film version of The Fountainhead was released in 1949. Although it used Rand's screenplay with minimal alterations, she "disliked the movie from beginning to end" and complained about its editing, the acting and other elements. Atlas Shrugged and Objectivism Following the publication of The Fountainhead, Rand received many letters from readers, some of whom the book had influenced profoundly. In 1951, Rand moved from Los Angeles to New York City, where she gathered a group of these admirers that included future chair of the Federal Reserve Alan Greenspan, a young psychology student named Nathan Blumenthal (later Nathaniel Branden) and his wife Barbara, and Barbara's cousin Leonard Peikoff.