Commited suicide at 34. The official cause of death was "a possible overdose of sleeping pills".
In a full-length article on Sidney in Classic Images, February 2009, by Greg Mank, Hollywood gossip had it that Sidney was having an affair with Carl Laemmle Jr., the Universal general manager who discovered her. Some implied that she also was having an affair with his father, mogul Carl Laemmle, at the same time. This sullied her reputation in Hollywood and her career was heavily damaged by it.
In the spring of 1932, she survived serious injuries after her car plummeted 40 feet down an embankment just outside her Hollywood home. She escaped with only cuts and bruises.
Stood at just four feet eleven inches tall.