Fewer than 50% of persons admitted to U.S. drug treatment programs complete them. Previous studies have associated decreased length of stay (LOS) with more negative treatment outcomes (e.g., resumption of drugs and alcohol, criminal recidivism, and unemployment), as well as societal outcomes that place a significant drain on the social welfare and healthcare system. A retrospective, correlational, causal modeling design was used to determine if weekday or weekend admissions to substance abuse detoxification and short-term residential (STR) programs contribute to LOS. A secondary purpose was to determine the influence of demographic and clinical factors on LOS. The study sample was comprised of admissions to public substance abuse treatment programs in Texas between 2002 and 2007 (N=39,866). For data analysis, the sample was randomly divided into three samples; consistent results of at least two were required for determining significance.

Results demonstrated that weekday admission to detoxification or STR was associated with increased LOS in treatment. While none of the demographic or clinical variables significantly influenced the day of admission, they did show some significant associations with LOS. Overall, about 50% of those entering detoxification had a psychiatric diagnosis on admission, and this percentage increased to 70% for weekend admissions. Demographic and clinical factors related to increased LOS in detoxification included (a) alcohol as the primary substance of abuse, (b) ethnicity other than Hispanic, and (c) age over 30. Females had a significant association with longer LOS in STR, while males did not. Less than 10 days of use of the abused substance prior to admission was significantly related to increased LOS in STR.

Testing the models with weekday or weekend admission as the mediating and the moderating variables demonstrated that the day of admission had no mediating or moderating effects in either detoxification or STR. While more research is needed to better understand the outcome of treatment success in substance abuse, the study results do provide implications and directions for future research and practice.