To explore whether relationships exist among the timeliness of access to outpatient (OP) and intensive outpatient (IOP) substance abuse assessment and treatment and the participation, retention and completion of treatment, admission data from the State of Maine substance abuse treatment data system, reflecting episodes both admitted and discharged during state fiscal year 2008 (N=6,157) were examined using linear and logistic regression techniques. Shorter wait times for assessment were found to lead to lower rates of treatment completion for both OP and IOP and to fewer numbers of sessions attended and shorter lengths of stay for IOP. Shorter waits between assessment and treatment were found to lead to lower attendance at OP treatment sessions, shorter lengths of stay for OP and IOP, but higher rates of treatment completion for IOP. Policy implications are discussed.
