Robin Williams' Son Zak Says Their Drug Abuse Was 'Similar': 'I Would Take Cocaine to Calm Down'

Zak said his late father would "use uppers as a way of focusing and relaxing."

Robin Williams' son Zak compared his struggle with mental health and addiction to his late father's, admitting they were "similar."

During his appearance on Prince Harry and Oprah's mental health series "The Me You Can't See," the 38-year-old actor said part of his battle since childhood was "inherited."

Prince Harry Talks Meghan, Diana's Death and Feeling 'Trapped' by Royal Family In Mental Health Doc

"There's a generational issue going on," he began. "I've experienced mental health issues my entire life. I had obsessive compulsive disorder -- having to count out certain actions before I went to bed at night, obsessing over things. I didn't sleep very much as a kid."

"I had really bad insomnia, a lot of energy and a racing mind and I inherited that to some degree," he added.

To help "calm" his inner thoughts, Zak said he began to rely on alcohol and drugs during his teens, which would eventually become a "very normal experience."

"It just became part of my identity," he explained. "I'm just like, 'I can do this so I can get through the day.' And the weird thing for me, I would take uppers. I would take cocaine and the like to calm down. I talked to my dad about it -- he was similar. He would use uppers as a way of focusing and relaxing."

"I started to realize elements of myself that were like him," Zak continued. "My anxiety, my bouts of depression, OCD, drugs, drinking like him."

After Robin decided to stop drinking, the pair grew a "deeper, more profound understanding of one another," according to Zak.

"Which is around the time that I first realized I had a problem," he claimed. "So we engaged around that. I wanted to be able to get to know him better, I didn't understand what he had been through."

Robin -- who was open about his battle with drugs and alcohol -- died at the age of 63 in 2014 by suicide.

"There were just things I wanted to tell him, and things I wanted to talk through with him," Zak said. "I did get the opportunity to do some of that but not to the level that I wanted to."

He said his life became "unmanageable" after his father's passing, with his excessive drinking getting out of control. But he soon realized he needed help, sought treatment, and became sober.

Now Zak is living his best life as father to two-year-old son, McLaurin (Robin's middle name), and husband to wife Olivia.

If you or someone you know is struggling with mental health or addiction, please contact the SAMHSA helpline at 1-800-662-HELP.