Michael Douglas' short-term memory "is not fine" anymore.

Michael Douglas

Michael Douglas

The 76-year-old actor can still remember things that happened a long time ago but has found his recall of recent events isn't what it was, which he had been attributing to previous marijuana use, but now he's not so sure.

He told AARP the magazine: "During this COVID-19 period, doing much more couch potato–ing, I have been shocked by the reduction of my stamina.

"And my long-term memory is fine, but my short-term memory is not. I used to blame it on pot. But I've got some friends who've been smoking as long as I have and have fabulous memories, so I don't think that's the issue. I'm researching it."

The 'Kominsky Method' actor - who has 42-year-old Cameron with ex-wife Diandra Luker and Dylan, 20, and Carys, 17, with spouse Catherine Zeta-Jones - admitted one of the hardest things he's had to do as a parent was "set boundaries" and put distance in place at the height of his eldest son's drug addiction struggles.

Asked the hardest thing he's done as a parent, he said: "Set boundaries, big and small. My older son, Cameron, was a drug addict and ended up serving seven and a half years in federal prison.

"That was hard, having to protect myself and my family and tell my older son that if you feel like I'm pulling away from you, I am, because I'm afraid you're either going to kill yourself or kill somebody else. That experience with Cameron I don't wish on anybody.

"There is a toughness that's required. But when you reach that point, you're doing it for your child."

Michael admitted he never realised how much "effort" it takes to be a parent until he had children himself.

He said: "[I was surprised at] how much of an effort it is [to be a parent]. You have to learn patience. We actors tend to be a little narcissistic."