Four interrelated studies on drug users in prison are presented within the framework of a proposed model for approaching the enhancement of health for persons that builds on an existential view of prisoners’ needs, as well as the risk management and “good lives” perspectives. Risk management is the major focus in current offender rehabilitation based on research on “what works ,” which has shown that focusing treatment on risk factors termed “criminogenic needs, ” such as impulsivity, poor family relations and drug abuse, reduces recidivism by 10-15 percentage points. The “good lives ” perspective proposes that offender rehabilitation should go beyond risk management and also address non-criminogenic needs such as autonomy, relatedness and competence as foundations for building personally meaningful lives.