Oppenheimer went into a deep depression after reading about the effects of the atomic bomb on Japan and even publicly spoke out against using the bomb

• J. Robert Oppenheimer "plunged into a deep depression" after he created the atomic bomb. 
• Historian Kai Bird said the physicist then began to publicly denounce use of the bomb. 
• At a meeting with President Harry Truman in 1945, Oppenheimer said: "I have blood on my hands." 

After leading the Manhattan Project and creating the world's first atomic bomb, J. Robert Oppenheimer had some regrets about his weapon. 

In fact, Oppenheimer "plunged into a deep depression" after reading news reports about what the atomic bomb did to the cities of Hiroshima and Nagasaki, historian Kai Bird — who wrote a book about Oppenheimer — told CBS News.