A depressed Scarsdale doctor mysteriously vanished Sunday — and her physician hubby has told cops, “I think she’s dead,” police said yesterday.

Dr. Mark Greenberg, 61, received a one-word text message from the cellphone of his wife, endocrinologist and mom of two Mona Shimshi Greenberg, 55, after she left the couple’s tony Tudor home at around 1 p.m. Sunday:

“Goodbye.”

Greenberg called the cops after his wife — who has been under psychiatric care — failed to return home by 6 p.m. Police tracked her cellphone, and at 9:35 a.m. yesterday, found her 2008, gray Honda CRV parked on the side of a desolate road leading to the NYPD shooting range at Rodman’s Neck in The Bronx.

Cops said it’s a missing-persons case. Still, her husband hired a lawyer on the advice of his rabbi.