Blight,
being physically addicted to a drug is scientifically proven. It's all about chemical balances in the body. You have chemicals and hormones in your body naturally, when your on something, your body produces less, or uses less. Glands in the body become dependent on certain drugs, produce less, or shut down. Just cause you tried a drug once doesn't mean your body is going to get addicted. That's why people get addicted so easily. Figure they can control their use at first and stop anytime, but once the body is hooked on a drug you're going to have to go through withdrawl to stop using.
And about it being a mind thing that everyone is capable of...bullshit.
People are born different, different body types, different intelligence, different attitudes and nature, different ways people think. No matter how much I believe or try, I will never be able to hit like Barry Bonds. Just like no matter how hard some junkies try, they will never be able to kick their habit by using their mind like you do (did).