Does substance use disorder affect clinical expression in first-hospitalization patients with schizophrenia? Analysis of a prospective cohort

Abstract

Although several papers reported a wide range of negative outcomes among patients with both schizophrenia and Substance Use Disorder (SUD), only a few studies evaluated the impact of SUD on psychopathology and thus on the length of first-hospitalization. The aim of the present study was to compare clinical expression of first-episode of schizophrenia between inpatients with and without SUD, giving close attention to the length of stay. One hundred and thirty inpatients at first-episode of schizophrenia were assigned to either SUD or not SUD group depending on SUD diagnosis and were assessed through BPRS at admission, during hospitalization and at discharge. Cross-sectional and longitudinal statistical analysis were performed to investigate differences between groups and also a linear regression was used to evaluate relationship between length of stay and BPRS scores. SUD group showed more disorganization at admission, less marked improvement of symptoms (disorganization, thought disturbance, anergia), and longer hospital stay than not SUD group. Moreover BPRS total score during hospitalization was a significant positive predictor for length of stay. Taken together, these findings suggest that SUD patients have a more severe and drug-resistant expression of schizophrenia, hence, they need longer treatment to achieve the overall symptoms improvement required for discharge.

Introduction

Comorbidity between Substance Use Disorder (SUD) and schizophrenia has been supported by the main epidemiological surveys. Epidemiological Catchment Area (ECA) study (Regier et al., 1990) reports a lifetime prevalence of 47.0% for some SUD in schizophrenia and it shows a 4.6 times higher risk of suffering from some SUD for schizophrenic subjects compared to general population. Similarly National Comorbidity Survey (NCS) (Kessler et al., 1994, Kendler et al., 1996) reveals 45% of comorbidity between substance abuse and schizophrenia while more recent National Comorbidity Survey Replication (NCS-R) (Kessler et al., 2005) reports 26.8% of lifetime comorbidity of non-affective psychosis with SUD. Furthermore, epidemiological investigations conducted outside United States support high prevalence of both substance abuse in psychotic disorders (Kavanagh et al., 2004, Addington and Addington, 2007) and SUD in schizophrenia (Fowler et al., 1998).

Some authors have also closely appraised the prevalence of the use of illicit drugs among psychotic patients. The substance most commonly used is cannabis, followed by cocaine, amphetamine, hallucinogen and other drugs (Allebeck et al., 1993, Hambrecht and Häfner, 2000, Compton et al., 2009, Compton et al., 2011). Moreover high frequency of polysubstance abuse and misuse are reported (Wade et al., 2006, Barnett et al., 2007). A true and accurate comparison between prevalences reported by different studies is also difficult because methods used for the assessment of substances use were more diversified (scrutinizing medical records, in-depth interview, urine drug test) as well as definitions of use/abuse (lifetime vs. actual use, abuse, or dependence).

From a clinical standpoint, comparison between psychotic patients with and without SUD has consistently shown that the former have an earlier age of onset and are more frequently male.(Cantwell et al., 1999; Veen et al., 2004; Henquet et al., 2005; Mauri et al., 2006; Koskinen et al., 2010; Mazzoncini et al., 2010; Barrigón et al., 2010). Several studies on schizophrenia have reported that patients with SUD have worse premorbid social functioning (Sevy et al., 2010, Mazzoncini et al., 2010, Compton et al., 2011, Schimmelmann et al., 2012), more severe symptoms at onset (Gearon and Bellack, 2000, Dawe et al., 2011), lower compliance and worse treatment response, thus more inappropriate use of mental health services, (Lambert et al., 2005, de Haan et al., 2007, Schimmelmann et al., 2012) with higher mental health costs (Bartels et al., 1993). However these findings about course of illness would be somewhat controversial (Cantor-Graae et al., 2001, Larsen et al., 2006, Zammit et al., 2008). As a matter of fact, some authors support a shorter duration of the illness (Dubertret et al., 2006) for substance-induced psychosis compared with primary psychotic disorders, especially when associated with protracted abstinence from substances (Dawe et al., 2011) and early intervention (Archie et al., 2007, Marshall and Rathbone, 2011). Studies on the course of schizophrenia have found that substance abusers not only have an higher frequency of relapse (Linszen et al., 1994, Rosenbaum et al., 2005), higher health care cost (Bartels et al., 1993) and a worse social adaptation (Caton et al., 2007), but also present several clinical conditions such as more severe hostile attitudes (Wade et al., 2006), more frequent thought disorders (Soyka et al., 2001) and fewer severe negative symptoms (Hambrecht and Häfner, 1996, Bühler et al., 2002, Compton et al., 2004, Bersani et al., 2002). Anyway, although SUD in schizophrenia has been associated with a wide range of negative outcomes, only a few papers have expressly investigated the different clinical expression of schizophrenia between patients with and without SUD, and thus whether the impact of substances on outcome is mediated by psychopathology. With certain exceptions (Mazzoncini et al., 2010), most of data obtained on this topic are inconclusive and inconsistent because they arise from studies concerning others clinical or management aspects of psychosis. However, the most frequently encountered symptoms in SUD are antisocial behavior (Hambrecht and Häfner, 1996, Rabinowitz et al., 1998), delusions, unusual contents of thought, hallucinations (Hambrecht and Häfner, 1996, Mauri et al., 2006, Sevy et al., 2010, Katz et al., 2010) and mood disorders (Linszen et al., 1994, Margolese et al., 2006). The aim of this study is to investigate the different clinical expression of early psychosis between patients with or without SUD in a prospective cohort of first-episode of schizophrenia, giving special attention to the relationship between duration of hospitalization and severity of symptoms and signs.