Drug addiction is where the subject craves/seeks drugs, despite negative consequences associated with drug use.
There is a difference between being addicted and drug dependence, it is possible to be dependent on a drug without being addicted. For example, people take drugs to treat diseases and disorders upon which they become dependent because their general health is improved because they take them.
These people are dependent on the drug, but are not addicted.
People who suffer from drug addiction take the drug regularly and experience extremely unpleasant symptoms if they discontinue taking them. This makes is seem almost impossible to stop.
There are other forms of substance abuse, for example glue-sniffing. Again, this forms an addiction.
After a thorough initial consultation it would decided which would be the best approach; it could be THRIVE and/or Pure Hypnoanalysis (analytical therapy) recommended as treatment for drug addiction, although it would be likely to be in conjunction with medical assistance if the addiction is serious. Again, this involves control, which can be dealt with by seeking the root cause of the reason why the subject felt the need to indulge in the first place.