Does the Minnesota 12 steps model really produce an effective change in the treatment of drugs addictions? The Minnesota 12 steps model claims to cure drug addiction, but doesn't deeply deal with the personality structure underlying addiction. We know today how addiction is a problem with an enormous range of factors causing it, being personality or/and psychopathology and coping strategies some of the most important. 

The method uses 12 steps to free individuals from drugs, but it doesn't use any deep approach to their personalities and its duration is also too short to do it ("The primary care program was intended to last up to 60 days in a residential setting", " "insurance companies then set 28 days as a reimbursement guideline in order to ensure sufficient coverage"(1).
There is even little evidence that this model is effective, and it received criticisms.  

Hence my questions:


Is it really producing changes, or only temporary changes which can collapse every time that personality is challenged?
Can it be realistically expected that the individuals treated by this method have their personalities really transformed and would never feel the necessity of consuming drugs, or have other type of addictive behaviours?


(1) http://www.ncbi.nlm.nih.gov/books/NBK64351/
Grønbæk and Nielsen (2007) conducted a randomized, controlled study of the Minnesota model for treating alcohol dependence in Denmark. 148 alcohol dependent individuals participated. The study reported a significant difference in alcohol abstinence between control and treatment groups when data was aggregated over the one-year period. However, by the end of the one-year followup period, this difference had disappeared. They concluded:


  Twelve months after onset of treatment, the Minnesota day clinic treatment does not differ in effect from the much cheaper ‘standard’ public treatment. However, patients in Minnesota treatment were total abstainers throughout a longer period.


References


Grønbæk, M., &amp; Nielsen, B. (2007). A randomized controlled trial of Minnesota day clinic treatment of alcoholics. Addiction, 102(3), 381-388.