Edwards died last month in Chicago after a long illness. He was 74.
The medical examiner’s finding confirms what the family said when announcing his death on Feb. 1.
Previous reports of elder abuse at the hands of his wife were unfounded.
Edwards replaced founding member David Ruffin in 1968 and was a member of The Temptations on and off for about two decades. He was inducted into the Rock & Roll Hall of Fame with the rest of the group in 1989.