Signed.
This doesn't seem to be thought out at all.
There are some benefit claimants- a very small minority- who spend all their money on drink and drugs. I wonder if anybody at the DWP has any idea what happens if a severe alcoholic suddenly goes cold turkey, without medical support? They are at risk of severe and possibly fatal fits.
In the real world, of course, this would never happen, as said alcoholic would simply flog his prepaid card down the pub for half its worth, and go without food completely so he could keep to his regular alcohol intake 
Perhaps if this government genuinely gave a shit about addicts, they would be investing in more desperately needed rehab facilities?
Except that they don't. The whole "addict" line is just a red herring to sell the idea to the Daily Mail readers, and they'll be trying to roll this out to cover normal families before you can blink.