However he tells the Times he is now healthy, no longer using hard drugs and is a "proud member of the beautiful HIV-positive community."
He says in the interview the memoir is a rare chance for him to be open and honest.
"I've had nightmares every night for the past three months because I'm scared to be this vulnerable with people," he says.
"It's hard for me to be as open as I want to be when there are certain things I haven't shared publicly... these are issues that need to be talked about."
He said one of the reasons he hadn't been able to be as open is because people only want to see his happy side.
"If you're having a terrible moment or in the middle of a conversation about something serious, people don't care. They want their bubbly J.V.N. and to get that major selfie."
This news comes after another interview with Out, in which Van Ness came out as gender-nonconforming and nonbinary.
Over The Top is due for release on September 24.