The Emmy Award-winning veteran actor and comedian died at his Connecticut home in July, and according to the doc -- obtained by TMZ -- the cause of death is listed "due to (or as a consequence of) Alzheimer's dementia." Translation ... there were complications resulting from Alzheimer's that caused his death.

It says he was diagnosed "years" before he passed. Torn was then buried at a cemetery in Poughkeepsie, NY a few days later ... according to the certificate.

Rip was perhaps best known for his role as Artie on HBO's "The Larry Sanders Show," for which he won an Emmy and was nominated 6 more times. He was also an Oscar nominee in 1984 for "Cross Creek."

Torn's career spanned decades after his film debut in the 1956 film, "Baby Doll," and included memorable roles in the 'Men In Black' films and "Dodgeball: A True Underdog Story" ... along with TV shows like "Will & Grace" and "30 Rock."

He was 88.