Dr. Drew: If Janice Dickinson Says Cosby Raped Her ... Then He Did

Dr. Drew has told a judge Janice Dickinson is a truth teller, and if she says Bill Cosby raped her then the court can take that to the bank.

Drew filed a declaration in Dickinson's defamation suit against Cosby, in which she claims he slandered her by claiming she lied about him drugging and raping her in 1982.

Drew says during the filming of 'Celebrity Rehab' in 2010, she told him she'd been raped by a "prominent celebrity" but was too scared to reveal his name. She's made statements to others before 2010, claiming the culprit was Cosby.

Drew says he found her to be an honest person. Indeed he says she's sometimes "overly honest ... blunt and unvarnished." He says, "she speaks the truth."

He goes on to explain her past addictions don't make her a liar for life ... "In my professional opinion, an addict may get clean and sober and become an honest and truthful person. I believe that has been the case for Ms. Dickinson."