Classical conditioning is widely used at behavioral therapy to associate uncondition and conditioned stimuli thus you may see a child responding appropriately just like Pavlov’s dog. So here conditioning is made with some future based ideal scenerio inorder to get appropriate response. In my opinion if we are applying this technique to a patient having diagnosis of substance use and induce so we can introduce aversive conditioning here inorder to deplete particular behavior , For example i may say that as long as you take the smoke in and take it out, you will experience certain nauseous sensations but you can get rid of then by throwing the cigrette away