Context

• Depression was widespread amongst the veterans of the Vietnam War. In fact, so many Vietnam veterans returned from the war with similarly negative psychological side effects that the healthcare industry was forced to come up with a name for this new phenomenon.
• In the 1970s, the term "post-traumatic stress disorder" (PTSD) came into use in large part due to the diagnoses of US military veterans of the Vietnam War. Veterans who witnessed the widespread bloodshed and trauma of the Vietnam War firsthand often became psychologically overwhelmed, sometimes not fully recovering if and when they were lucky enough to make it home after the war.
• War is never directly referenced in “Paint it Black,” but the depressed song lyrics echo feelings shared by many during the Vietnam War—civilians and soldiers alike. By the time the song “Paint it Black” was released in 1966, public opinion was already turning against the Vietnam War, which for many seemed to drag on endlessly with no end in sight. By 1970, the majority of Americans believed that the U.S. had made a mistake by sending so many troops to fight and die pointlessly in Vietnam. War and all of the death caused by it were definitely on people’s minds. 
• "I see a line of cars and they’re all painted black With flowers and my love, both never to come back."