Cameron Douglas Says Drugs Were a 'Path Out of Loneliness' Until He Got Sober in Prison

Cameron Douglas can’t pinpoint just one thing that led him down the dark and self-destructive path of drug addiction.

While a potential genetic predisposition for addiction likely played a role — among other Douglas relatives who’d struggled with alcohol, his uncle Eric died at age 46 from a drug overdose — Cameron, 40, says drugs helped him find his way.

“The ups and downs of drug addiction are entirely predictable…There’s a comfort in that,” Cameron writes in his upcoming memoir, Long Way Home, excerpted exclusively in this week’s issue of PEOPLE.

“[Drugs] were, for me, a path out of loneliness.”

What started as teenage bouts of drinking, pot-smoking and hijinks escalated into a tsunami of hard-core addiction for Cameron — and caused never-ending worry for his father, Hollywood star Michael Douglas, and mother, Diandra, 63, a former model and producer.

• For more about Michael and Cameron Douglas, pick up the latest issue of PEOPLE, on newsstands Friday.

As an only child to an increasingly famous father who was often away and a very young mother, “I was maybe trying to make sense of things… and trying to figure out where I fit in,” he tells PEOPLE.

“Then there were the awkward [teen] years and for whatever reason, I started drifting towards kids who were smoking, drinking and [other] things and I tied that in with friendship…and then it just kept going from there,” he says.

Before long, Cameron was abusing cocaine and heroin. By his 20s, he was carrying a gun and dealing methamphetamines to support his spiraling habit.

“I hated the wreckage I saw in my life because of drugs, but I just couldn’t stop,” says Cameron, who at one point shot up cocaine daily and withstood drug-induced seizures.

RELATED: Michael Douglas on Son Cameron’s Harrowing Drug Addiction: ‘I Thought I Was Going to Lose Him’

“It’s the sneaky power, the stranglehold that addiction has when you’re in the throes of it,” he says. “When you get that far down the rabbit hole, there are a couple options: there’s prison and then there’s death.”

Cameron narrowly escaped the latter, but in 2009 a DEA sting operation landed him behind bars. He faced a five-year term for conspiracy to distribute meth and cocaine. After the sentence was extended by another five years for possession while he was incarcerated, “something inside me broke,” he says.

That low point also marked the start of a gradual turnaround. He got sober in prison and focused on his future for the first time in decades.

“For a long time I quite honestly thought I just wasn’t put together properly, that I didn’t have the characteristics necessary for real success in life,” says Cameron, who spent nearly eight years in prison before being released in 2016.

“I know now that was the addiction talking.”

Today, Cameron is raising his beloved 22-month-old daughter Lua with longtime girlfriend Viviane Thiebes, 41, a yoga instructor, working on restarting his acting career and feeling deep gratitude that his family never gave up on him.

Determined to help other addicts “seek help – and maybe save a life,” Cameron shares his harrowing and ultimately inspiring journey in Long Way Home, which hits shelves Oct. 22.

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