Watch: Leading Forensic Psychiatrist Evaluates Mel Gibson Rant

ET asked Steven Pitt, one of this country's leading forensic psychiatrists, to evaluate one of Mel Gibson's shocking, expletive-laced phone tirades against ex-girlfriend Oksana Grigorieva.

"When you listen to him, he talks to his ex-girlfriend as if she's an indentured servant. So to say that he has issues is really being kind," Pitt says.

"The one thing we do know for sure is that in the past, Mr. Gibson's alcohol consumption has gotten him into trouble with the law. So the big question becomes: Did alcohol and/or the use of illicit substances play a role in his behavior?"