“…A continuous age variable was included to further control for an individual's specific age. A dummy variable for a substance abuse diagnosis was added as a proxy for dual diagnosis Macias et al, 2006), because substance abuse is known to complicate the treatment of severe mental health conditions (Dickey, Fisher, Siegel, Altaffer, & Azeni, 1997). The total number of months a beneficiary was enrolled in Medicaid during the study period was included to account for the increased opportunity an individual has to accumulate cost as the number of enrollment months per member increases (Clark, Samnaliev, & McGovern, 2009;Thomas et al, 2005).…”