Michael Douglas has vowed to fight for a complete overhaul of America's legal system after lawmakers upheld his son's lengthy prison sentence on drug charges. The Wall Street star's son, Cameron, is serving five years behind bars for distributing drugs, but his sentence was doubled in 2011 after he committed several infractions behind bars, including smuggling medication into his prison cell. Douglas helped his son challenge the increased sentence, but in April (13), lawmakers at the U.S. Circuit Court of Appeals in New York refused to overturn the ruling, meaning Cameron will remain in prison until 2018. The Oscar-winner has now revealed he was left distraught after losing the appeal and he is determined to campaign to help change the way addicts are treated behind bars. He tells Britain's Event magazine, "I cried (when we lost the appeal). It is the last time I cried. I don't know how else to say this other than it broke my heart. You have a vision of someone you love and care about and it feels unfair and you are helpless. It's been my trial. My tragedy. We've struggled together since he was 13." Douglas is adamant his son was treated unfairly, and he now wants to campaign for changes to the way drug addicts are handled by the legal system. He adds, "I have an issue with the court and prison system, about how we treat non-violent drug addicts. His punishment is too harsh. I want to get involved in working out reforms. I know a lot about it now. Cameron got the most severe sentence in the history of the U.S. penal system. It's just unrealistic. My son deserved to get arrested, but not to be harshly punished for obtaining drugs in prison.