Despite the overall low rates of treatment participation, patients with substance use disorders (SUD) are regularly dissuaded from initiating treatment until they are willing and able to commit to sustained abstinence from all substances. To improve population outcomes, it is important to reach those who are not engaged in treatment and increase retention of those who do engage in care. To do this, treatment providers must proactively engage individuals in care, including those who are uninterested or ambivalent about treatment, and design services with the intention of increasing patient retention.