But with the cause of death still to be determined, a close pal of Sylvester Stallone's eldest son is hoping to clear up any misconception regarding Sage's condition in the final days of his life.
First of all, friend Stephen Wozniak says, he does not for a minute believe that Sage took his own life.
Sage's death was "absolutely not suicide," Wozniak says in an exclusive interview with E! News.
"I spoke to him a few weeks ago," he recalls. "We talked about resurrecting a film we worked on, other projects, talked about his girlfriend and time they'd spent together. We talked about my wedding and he seemed to be thinking about it."
"I'm certain that this really horrible thing that happened was an accident," Wozniak says. "It could have been anything—but nothing like suicide. I knew him pretty well."
He says that Sage, whose mother was Stallone's first wife, Sasha Czack, suffered from anxiety; Wozniak says he saw prescription medications like Vicodin, Klonopin and Paxil at his friend's house.
Sage smoked two or three packs of cigarettes a day, Wozniak says, but did not use recreational drugs. Wozniak also says that he never saw his friend "drink or party."
"He would withdraw and get depressed," Wozniak says of Sage. "He would try to overcompensate. He would try to clown around and I know that those are things people do, medicate or wake up. He was no different. Very few people were telling him 'don't do that.' I did. He was very resistant when [you would tell him that]. It was a sore point with him."
An autopsy on Sage was deemed inconclusive pending the result of toxicology tests and the LAPD placed a security hold on the coroner's findings.
"He was private," Wozniak continues, calling Sage "rightfully guarded." He spent "a lot of time in his place. He could spend weeks alone, go on mountain vacations on his own."
Wozniak also says that Sage would get picked on at school by "a lot of rich kids" who would ask him why he wasn't a "tough guy" like his dad.
"He didn't like it, who would?" Wozniak said of his friend, who made his acting debut playing his father's son in Rocky V. "[Sage] first decided, 'I'm not going to engage in that game. I'm going to go the other direction.' That's why he released these amazing films."
At one time, Sage did have a difficult relationship with his father, according to Wozniak. "I think there was a period from the time his parents divorced, where there was more of a disconnect. And I think as a kid that acts out, he had a lot of difficulty with his dad. He said he spent less time with him.
"One way or another,"he added, "whether it was with age, or spending more time with his dad during the holidays, [their relationship] became increasingly better. I think they developed a great bond."
Sage was a "pretty amazing guy," Wozniak said. "Creative, thoughtful." He was "interested in people and how they got to
where they were."
Wozniak said Sage was also "very funny," a "big joker in his own way...He loved absurdist humor. He saw irony in life."
"He was a wonderful guy who loved life and was so sensitive that it got to him."