Michael Douglas' incarcerated son has written an emotional online blog urging U.S. officials to help drug addicts rather than lock them up.

Cameron Douglas was sentenced to five years behind bars in 2010 after pleading guilty to distributing drugs. His sentence was doubled in late 2011 after he committed several infractions behind bars, including smuggling medication into his cell.

Now, the 34 year old has opened up about his struggle with addiction in an article for The Huffington Post, criticising the legal system in America for punishing addicts with jail time instead of providing treatment.

He writes, "There are half a million other people in the U.S. who, like me, will go to sleep behind bars tonight because of nothing more than a drug law violation... This outdated system pays little, if any, concern to the disease of addiction, and instead punishes it more harshly than many violent crimes...

"I'm not saying that I didn't deserve to be punished, or that I'm worthy of special treatment. I made mistakes and I'll gladly and openly admit my faults. However, I seem to be trapped in a vicious cycle of relapse and repeat, as most addicts are. Unfortunately, whereas the effective remedy for relapse should be treatment, the penal system's 'answer' is to lock the door and throw away the key.

"Somehow... no one seems to comprehend that tossing individuals desperate for skills to cope with addiction behind bars... does absolutely nothing but temporarily deter them from succumbing to their weakness. Instead of focusing on how many individuals this county can keep imprisoned, why can we not focus on how many individuals we can keep from coming back?"

Douglas is due to walk free in 2018.