Elsevier

Schizophrenia Research

Volume 206, April 2019, Pages 257-262
Schizophrenia Research

Characteristics and outcomes of young people with substance induced psychotic disorder

https://doi.org/10.1016/j.schres.2018.11.007Get rights and content

Abstract

Background

Substance induced psychotic disorders (SIPD) have been historically considered as associated with better clinical and functional outcomes than other psychotic diagnoses. As a result, treatments for those with SIPD are often considerably less intensive, yet this is not based on evidence. The present study aimed to examine whether differences exist between those with SIPD and other first episode psychosis (FEP) diagnoses in regards to demographic and clinical factors, and to determine the symptomatic, clinical and functional outcomes in those with SIPD.

Methods

This study included all young people aged 15–24 who presented with a FEP to the Early Psychosis Prevention and Intervention Centre between 01/01/2011 and 31/12/2013. Group differences were analysed with independent samples t-tests and chi-square analyses and equivalent non-parametric tests as appropriate. Where applicable, odds ratios were calculated.

Results

544 young people presented with a FEP and 10.3% (N = 56) were diagnosed with SIPD. Individuals with SIPD were more likely to be male, unemployed, and have a comorbid substance use disorder. There were no significant differences between groups regarding duration of untreated psychosis, severity of psychotic symptoms, time to remission, or rates of relapse. Those with SIPD were less likely to be employed or engaged in study at discharge and 35.7% of those with SIPD had a change of diagnosis to a schizophrenia spectrum or bipolar disorder after a median of 84 weeks.

Conclusion

Young people diagnosed with SIPD should be an important focus of early intervention services and receive comparable treatment to those with other psychotic diagnoses.

Introduction

A small but significant proportion of individuals presenting with a first episode of psychosis (FEP) will receive a diagnosis of substance induced psychotic disorder (SIPD). This diagnosis has attracted criticism, as a large proportion of individuals with a psychotic disorder will also have a concurrent substance abuse disorder (Jablensky et al., 2000; Wilson et al., 2017) and thus accurate diagnosis can be difficult (Mathias et al., 2008). Despite this, individuals with a diagnosis of SIPD are often excluded from research studies (Jorgensen et al., 2000), have shorter periods of clinical care (National Institute for Mental Health in England, 2008), and have longer delays to care post first referral to services (Kirkbride et al., 2017). This practice is however counter-intuitive, considering that SIPD is a psychotic disorder which warrants appropriate treatment, and that the diagnosis is associated with a high risk of subsequently developing schizophrenia. Specifically, between 25 and 46% of individuals with SIPD transition to a schizophrenia spectrum disorder, often within three years of first service presentation (Arendt et al., 2005; Caton et al., 2007; Crebbin et al., 2009; Niemi-Pynttari et al., 2013).

In addition to this, individuals with SIPD present with more severe depressive symptoms and suicidal ideation (Caton et al., 2005; Nunez and Gurpegui, 2002), and similar levels of positive symptoms, quality of life, functioning and relapse rates compared to individuals with other psychotic disorders (Thompson et al., 2016), though are more likely to lose contact with mental health services (Crebbin et al., 2009). Further, individuals with a concurrent psychotic disorder and cannabis abuse disorder are more likely to present at a younger age (Large et al., 2011; O'Donoghue et al., 2015) and any substance misuse has been associated with increased risk of inpatient admission and earlier relapse of symptoms for those with FEP (Wade et al., 2006). All of these clinical factors provide a strong justification for a need for care within this FEP sub-group, however contention still exists about where those diagnosed with SIPD should receive treatment, what treatments they should receive, and for how long.

This study aims to add to the current literature with an epidemiological longitudinal examination of those presenting to an early intervention service with a SIPD compared to those with other affective or non-affective first episodes of psychosis. Specifically, the study aims to determine:

  • (i)

    the proportion of young people presenting with a SIPD

  • (ii)

    whether demographic and clinical characteristics are associated with a diagnosis of a substance induced psychosis

  • (iii)

    rates of remission and relapse in the SIPD group compared to other FEP diagnoses

  • (iv)

    functional outcomes, in regards to education and employment, in the SIPD group

  • (v)

    the proportion of those who have a diagnosis of SIPD at presentation and who later fulfil criteria for a different psychotic disorder

Section snippets

Participants

This study included an epidemiological cohort of 544 young people with a diagnosis of a first episode of psychosis (FEP) who received treatment at the Early Psychosis Prevention and Intervention Centre (EPPIC).

Setting

EPPIC is a comprehensive treatment program within Orygen Youth Health (OYH) for young people aged 15 to 25 years with a FEP in the north-western regions of Melbourne, Australia. This catchment area covers more than one million people and EPPIC provides services to approximately 400 people

Demographic characteristics of cohort

The cohort consisted of 544 individuals, 325 of whom were male (59.7%). At service entry, the mean age of the cohort was 19.5 years (sd ± 2.9). The median length of time in service was 84 weeks (I.Q.R. 53, 101). Table 1 details the demographic and clinical characteristics of the cohort.

Diagnosis and duration of untreated psychosis (DUP)

Fifty-six individuals in the cohort had a diagnosis of a SIPD (10.3%) at three months of service engagement. A complete list of diagnoses is detailed in Table 1. The mean DUP in the cohort was 25.4 weeks

Discussion

There are a number of important findings from this study. First, there were minimal differences in the clinical characteristics and outcomes of those with a SIPD compared to other psychotic disorders. As would be expected, those with a SIPD were more likely to have a concurrent substance abuse disorder, but notably, there was no difference in regards to psychotic symptom severity, remission and relapse rates, and DUP. In the only difference between groups, the SIPD group faired worse in regard

Conclusion

Young people with SIPD experience similar severity of psychotic symptoms and rates of relapse and remission to those with other FEP diagnoses, though experience poorer vocational outcomes as explained by cannabis use. This study does not lend evidence to the widely held view that less intensive treatments are required for those with SIPD and suggests such individuals should be an important focus of engagement and treatment within early intervention for psychosis services. Continued review of

Conflict of interest

All authors declare that they have no conflicts of interest.

Contributors

Jessica O'Connell conducted literature searches and wrote the first draft of the manuscript. Monica Sunwoo and Patrick McGorry assisted literature searches and contributed to the writing of the introduction and discussion. Brian O'Donoghue designed the study, wrote the protocol, and conducted data analysis. All authors contributed to and have approved the final manuscript.

Role of the funding bodies

Dr. Brian O'Donoghue is a recipient of a NHMRC Early Career Fellowship.

Acknowledgments

We thank Meghan Bowtell, Scott Eaton, Melissa Bardell-Williams, Linglee Downey, and Kristen Thien who completed data collection for this study.

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