Throughout the 1970s, gay activism had significant successes. One of the first and most important was the "zap" in May 1970 by the Los Angeles GLF at a convention of the American Psychiatric Association (APA). At a conference on behavior modification, during a film demonstrating the use of electroshock therapy to decrease same-sex attraction, Morris Kight and GLF members in the audience interrupted the film with shouts of "Torture!" and "Barbarism!" They took over the microphone to announce that medical professionals who prescribed such therapy for their homosexual patients were complicit in torturing them. Although 20 psychiatrists in attendance left, the GLF spent the hour following the zap with those remaining, trying to convince them that homosexual people were not mentally ill. When the APA invited gay activists to speak to the group in 1972, activists brought John E. Fryer, a gay psychiatrist who wore a mask, because he felt his practice was in danger. In December 1973—in large part due to the efforts of gay activists—the APA voted unanimously to remove homosexuality from the "Diagnostic and Statistical Manual".