In contrast to our study, in 71,225 Massachusetts Medicaid beneficiaries, Medicaid beneficiaries with dual diagnoses had more (odds ratio 6–8) deaths than those with only a psychiatric disorder. This study, however, lacked comprehensive data on diagnoses and did not control for treatment environment. The authors explained this by the disproportionate number of deaths that were injury deaths, homicide, suicide, and accidents (Dickey et al., 2004). Our study did not have details on injury deaths, homicide, suicide, and accidents. After adjusting for age, 2416 individuals discharged from Washington State mental hospitals with mental illness and SUD had a 44% higher risk of death than individuals with mental illness and SUD only (Maynard et al., 2004). These two studies did not assess medical sequelae of substance use. The risk-adjusted probability of mortality over a 7-year period among 169,051 male veterans with or without co-occurring SUD was 55% higher among veterans with dual diagnosis than among those without SUDs (Rosen et al., 2008). This study controlled for preexisting medical conditions in contrast to the two studies mentioned above (Dickey et al., 2004; Maynard
