In 2007, an estimated 22.3 million people in the United States, aged 12 or older, were classified as meeting the criteria for either substance dependence or abuse. Therapists have long sought to discover the most effective way to address these disorders in therapy; though short-term gains are often seen following inpatient or outpatient treatment, these gains often dissipate over time. Individuals who attend support groups such as Alcoholics or Narcotics Anonymous or SMART Recovery show much better prognoses over time than those who receive formal treatment alone. The current research is a secondary analysis of data collected by the Drug Abuse Treatment Outcome Study. A path analysis is conducted to examine the relationships between symptoms of depression, symptoms of anxiety, and motivation for treatment as they relate to post-treatment support group attendance. These variables form a path model which is analyzed so that each individual regression takes into account the other regressions in the model. Symptoms of depression are found to be significantly positive predictors of motivation for treatment, and motivation for treatment is found to be a significantly positive predictor of support group attendance. Implications of these findings for clinical practice and future directions for research are included in discussion of the results.