Persons with SC have substantially higher lifetime risk of having SUD than do persons from the general population (McCreadie, 2002; Kessler et al., 2005; Regier et al., 1990; Ringen et al., 2008; Soyka et al., 2001; Swartz et al., 2006), ranging from 40% to 60% (Cantor-Graae et al., 2001). In the US, an epidemiologic study found lifetime history of comorbid SUD was 47% for persons with SC or schizophreniform disorder, a rate 4.6 times higher than for the general population (Kavanagh et al., 2004). In a recent nation-wide study of SC in the US, even higher rates of SUD were found: 60.3% of 1460 persons with SC reported a SUD (Rosenmanet et al., 2000). Similar high rates of SUD with SC have been found in studies from Europe (Dervaux et al., 2001; Fowler et al., 1998; Kavanagh et al., 2004; Menezes et al., 1996; Ringen et al., 2008; Rosenman et al., 2000; Verma et al., 2002).
