You probably know that the brain learns by doing. What you may not know is that the brain also learns by cause and effect. This is especially evident when the subject has ever used any drug at any time for any reason.
In hypnosis, after you learn what highs and experiences a person has had, you can suggest a person feels any number of highs or euphorias. The human brain, once programmed by an experience, can re-create the intoxicating effects without ever taking the drugs again.
Now, if we are working with someone in severe detoxification, the possibilities of having freely recreated euphorias can be very helpful. For one, the person gets to have the experience without taking the drug. Secondly, the euphoria lasts longer, and finally, the experience has no side effects for it is mentally induced. However, I personally make some very severe exceptions:
If any patient is driving any motor vehicle, I say, "These suggestions of euphoria will never work if any sign of danger or trouble exists. The effect will immediately go away, and be replaced by concentration, motivation and adrenaline to take care of the problem. You will never ignore a problem, but act upon it and make it go away the effective way, by resolving it."
I find that a lot of drug users have tried over five types of drugs. I ask them for their five favorites, and then, using their right hand, ask them to label which is the first, second, third, fourth, and fifth favorite of these, and count them off using their fingers. I then tell them that each finger is now labeled, and if they choose to do self hypnosis, and once they relax to about this level, they can stick up what fingers they wish to feel in their euphoria, and it will just happen.
One funny note: I did a session with a guy one night. I pinched the air (I had nothing in my hand) and pretended to inhale from an imaginary hand rolled marijuana cigarette. I pretended to be holding my breath with the imaginary smoke, and then passed my imaginary "joint" to this guy. As he inhaled from his fingers, I suggested that he got "Stoned-er and stoned-er." Although his relaxation was admirable, the fact that his eyes turned blood-shot red, just as they would if it were real, was a shock to me. The brain recreated every effect of the pot, even if there wasn't any.
I have found that suggestions relating to certain drugs need to be defined. Make certain to suggest that these are "good highs" as long as they are using the hypnosis to replace the drug use. I have seen use of negative reinforcement with getting people to stop using drugs, but this approach allows them to stop using them by giving them the high without having to ever pay for it again.