Substance misuse in first-episode psychosis

Introduction Substance misuse is one of the most challenging issues for clinicians in the management and treatment of first-episode psychosis (FEP). The aims of this chapter are to (1) review current knowledge about substance misuse and regular tobacco use in FEP, (2) describe hypotheses that have been proposed to explain the high rate of substance misuse among individuals with psychosis, (3) review the evidence for the efficacy of psychological interventions for substance misuse and regular tobacco use in psychosis, and (4) provide guidance to clinicians in implementing psychological interventions for substance misuse in FEP. In the current chapter, substance misuse refers to substance abuse or dependence, although low levels of substance use may be associated with problems in people with severe mental disorders (Kavanagh, Mueser & Baker, 2003a). Substance misuse and regular tobacco use in first-episode psychosis Rate and patterns Individuals with psychotic disorders are at increased risk for substance misuse compared with individuals with other common psychiatric disorders (Regier et al., 1990) and the general population (Degenhardt & Hall, 2001; Regier et al., 1990). Consistent with these findings, individuals with FEP have a significantly higher rate of substance misuse than their non-psychotic peers (DeLisi et al., 1991; Hambrecht & Häfner, 1996). Estimates of the rate of lifetime substance misuse in individuals treated for FEP have varied widely, ranging from 10% (Verma et al., 2002) to 74% (Lambert et al., 2005), with most studies in Australia and the USA reporting a rate of at least 40% (DeLisi et al. 1991; Lambert et al., 2005; Rabinowitz et al., 1998; Strakowski et al., 1998; Wade et al., 2005).