Associations between polysubstance use and psychiatric problems in a criminal justice population in Sweden

Abstract

Background

Polysubstance use is common in substance users, and may complicate their clinical course. This study, in a criminal justice setting in Sweden, examines the association between the number of concurrently used substance types and psychiatric symptoms during 30 days before incarceration, while controlling for background variables such as family history (drug and alcohol problems, psychiatric problems, criminality), demographic data and history of emotional, physical or sexual abuse.

Methods

The data material comprised 5659 criminal justice clients reporting a substance use problem, examined with the Addiction Severity Index. Variables were compared in a multinomial regression analysis, comparing clients reporting one (n = 1877), two (n = 1408), three (n = 956), four (n = 443) and five or more (n = 167) substance types.

Results

The 30-day prevalence of most psychiatric symptoms included in the study (depression, anxiety, cognitive problems, hallucinations, difficulty controlling violent behaviour, suicidal ideation, suicide attempts) was higher in individuals with a higher number of concurrent substance types used. In multinomial regression analysis, while controlling for background variables, these associations remained for concurrent suicidal ideation, cognitive problems, hallucinations and violent behaviour, with the latter two being associated with the higher numbers of substance types. Binge alcohol drinking, tranquilizers, opioids and the number of substance types reported were associated with several of the psychiatric symptoms.

Conclusions

In the present criminal justice setting in Sweden, the use of multiple substance types and concurrent psychiatric symptoms appear to be associated, and a sub-group reporting particularly high numbers of concurrent substance types are particularly likely to report potentially severe psychiatric problems.

Introduction

Polysubstance use is commonly reported in clinical populations of alcohol and drug users (Darke and Hall, 1995, Gossop et al., 1998, Kedia et al., 2007, Martinotti et al., 2009). The misuse of different substances, simultaneously or within a short period of time, has been described as representing a pattern of drug use with particularly problematic features. Polydrug use also has been shown to be associated with non-fatal and fatal drug overdose (Coffin et al., 2003, Darke et al., 2005, Warner-Smith et al., 2001), and with attempted suicide among substance users (Darke et al., 2007, Martinotti et al., 2009), and polydrug use appears to be a risk factor for prospective death in substance users seeking treatment (Gossop et al., 2002). Polydrug use may complicate treatment, such as in heroin users who also use cocaine (Williamson et al., 2006), and a link between psychiatric comorbidity and polydrug use has also been demonstrated among clinical substance use patients (Carrà et al., 2006, Marsden et al., 2000) and in a twin study (Lynskey et al., 2006). Pirard et al. (2005) reported from a population examined with the Addiction Severity Index (ASI) that substance users with a history of sexual or physical abuse may have more polydrug use and more severe psychiatric problems. It has also been reported that self-reported childhood trauma may be more common among polysubstance users than among monosubstance users (Martinotti et al., 2009), and that childhood sexual abuse may be associated with subsequent polysubstance use in adolescence (Shin et al., 2010).

In addition to the literature describing higher problem severity in polydrug users, there is also, more specifically, data indicating that a higher number of abused substances may be associated with a more severe clinical picture. An association has been seen between the number of drug dependence diagnoses and the number of comorbid psychiatric diagnoses in heroin injectors (Darke and Ross, 1997). It has also been reported that suicidal behaviour (Borges et al., 2000) and the risk of unnatural death in substance users (suicide or drug overdose) were associated with the number of addictive substances used (Bradvik et al., 2009).

The present study intended to test the hypothesis that the use of a larger number of substance types may be associated with a higher prevalence of psychiatric problems, in a large database of interviews with substance users in the Swedish criminal justice system. In this setting, we aimed to examine a potential association between the number of concurrent substance types used and the prevalence of psychiatric symptoms within the same narrow time frame (30 days). Also, the study aims to examine this association when controlling for family background factors, history of emotional, physical or sexual abuse, and demographic data.