Understanding Evidence-Based Practices – Just as treatments for other chronic illnesses change based on new advances in research and science, so, too, do treatments for substance abuse and mental disorders, whether occurring separately or co-occurring in a single individual. The challenge to mental and substance abuse professionals – and to the field as a whole – is to ensure that the services being provided, in fact, are the most appropriate for the individual and are the best possible from the perspectives of effectiveness and appropriateness. Those principles undergird the concept of evidence-based services and evidence-based practice