There is a flip side to this question.
Most addicts will do just about anything to feed their addiction. Many a “frum” girl will sell her body and “frum” men will steal to get their needed fixes. So while your money will indeed be used to temporarily satisfy the addiction, you are also preventing additional aveiros.
Other issues: What about the tobacco addict; $25 of your tzedaka gets burned up every day, or about $8000 a year, to the poor guy who smokes.
And what about the fat collector? If the poor schnorrer is obese and can’t control his food cravings, your tzedaka money is going to the pizza store or restaurant across the street.
And what if the poor guy loves fine wine and spirits?
The only criteria that the torah mentions is that you are to give to your poor brother; the rest is up to him.