A new study may change the way clinicians make treatment decisions for their patients who smoke. The findings suggest that current treatment theories that maintain any smoking after the planned target quit day predicts treatment failure need to be expanded to take into account a more dynamic quitting process. The research points to two types of successful quitters: those who quit immediately and remain abstinent through the end of treatment and those who are "delayed" in attaining abstinence but achieve success by the end of treatment.