Michael Douglas's son feels ''thoroughly blessed'' to have the support of his family during his time in jail.

Cameron Douglas, 34, whose five-year sentence for heroin possession and conspiracy to distribute narcotics in 2009 was extended by four and a half years in 2011 for committing drug infractions behind bars, admits he is ''trapped in a vicious cycle of relapse and repeat'' in jail, but claims that one of his positive drug tests was actually false.

In a lengthy blog post on the Huffington Post on Tuesday (11.06.13), Cameron wrote: ''I have spent close to two of my four years of incarceration in solitary confinement. If this seems like a long time, it is magnified in light of the fact that my time spent in the box is largely due to two dirty urines -- one of which was false, which is a story for another time.

''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.

''Nevertheless, I feel thoroughly blessed. I have a beautiful and loving family who has faithfully supported me every step of the way, believing in me and refusing to give up in the face of one bleak adversity after the next.''

Cameron - whose stepmother is Catherine Zeta-Jones and who has a half-brother, Dylan, 12, and a 10-year-old sister Carys - has developed a ''strong faith'' in prison in Loretto, Pennsylvania, despite his ''painful journey,'' which he hopes will help him to help others in a similar situation.

He added: ''Maybe one day, my family, my future children, and whomever I have the privilege of coming to know, will be able to regard me as a man who endeavoured to leave this planet just a little better than the way I found it.''