Third, risk assessment (which can apply to those factors that can be manipulated as well as those that cannot) can be used to direct motivational enhancement intervention. The main purpose of the DISC study was to evaluate the effectiveness of PTC (a specific motivational enhancement intervention). The findings supported the efficacy of PTC compared to TAU. As additional motivational enhancement interventions are developed and shown to be effective, mprovingreadiness to change directly will be more achievable.