How do physician practice patterns affect the evaluation, treatment, and quality of treatment for alcohol, drug and mental disorders (ADM)? Specifically, the researchers tested the effects on treatment of seven markers of physician practice patterns (1) ease of referral; (2) propensity to refer; (3) physician perceived autonomy; (4) intensity of clinical care; (5) physician self-reported use of clinical guidelines and/or patient satisfaction surveys; (6) time available to spend with patient; and (7) continuity of care. In addition, the researchers analyzed how organizational structure and financial mechanisms affect two key markers of psychiatric practice patterns, the psychiatrist’s ability to provide appropriate continuity of care and the psychiatrist’s propensity to utilize clinical guidelines. The researchers built on other work in which they used individual level HealthCare for Communities data to investigate the patterns and predictors of ADM evaluation and treatment in outpatient primary care settings. The objective of this study was to better understand the relationship between physician practice patterns and the likelihood of evaluation, treatment and guideline-concordant care for alcohol, drug, and mental disorders, with the ultimate goal of implementing policies that meet the treatment needs of individuals with these disorders.