Social environmental risk factors for transition to psychosis in an Ultra-High Risk population
Introduction
Over the last two decades, significant progress has been made in prospectively identifying the symptoms and characteristics of the prodromal phase of psychotic disorders (Yung and Nelson, 2011). This has resulted in the ability to identify individuals at higher risk of psychosis compared to the general population, with over one third of these ‘clinical high risk’ individuals subsequently developing a psychotic disorder within three years (Fusar-Poli et al., 2012). The ultimate purpose in identifying this group is to prevent the first episode of psychosis and a recent meta-analysis has demonstrated provisional success on this front, with the overall effect of diverse interventions, specifically, CBT, omega-3 fatty acids and antipsychotic medications, having a risk reduction of 54% at 12 months with a number needed to treat of 9 (van der Gaag et al., 2013). Further factors that may influence the risk of progression to a psychotic disorder in UHR populations have been identified, specifically low functioning, longer duration of symptoms (Nelson et al., 2013) and unusual thought content such as suspiciousness (Cannon et al., 2008, Ruhrmann et al., 2010, Thompson et al., 2011). Cognitive deficits, a core feature of schizophrenia, are more prevalent in UHR individuals compared to healthy controls and are associated with a higher risk of transition to psychotic disorders (Bora et al., 2014). Neuroimaging studies have identified that people who are UHR for psychosis show some brain alterations in comparison to healthy controls, but there is a lack of consistent findings as to which of these alterations is associated with transition to psychosis (Wood et al., 2013). Genetics studies may also contribute to predicting those at higher risk of psychotic disorders, with certain genetic variations, such as in neuregulin 1, increasing the risk of transition in the UHR population (Bousman et al., 2013). However, while there appears to be a wide range of factors associated with transition to psychotic disorders in the UHR population, the findings of a number of these factors are yet to be replicated.
Despite the established association between psychotic disorders and social environmental risk factors, such as social deprivation, urbanicity, migrant status and social adversity (Morgan et al., 2008, Kelly et al., 2010, Kirkbride et al., 2012), there is a paucity of research in this area in the UHR population. In the Netherlands, Dragt et al. found that UHR individuals living in an urban environment or receiving state benefits were more likely to transition to psychosis (Dragt et al., 2011). Furthermore, the study found that ethnicity, birth place, obstetrical complications and employment status were not associated with an increased risk of transition. Velhorst et al. identified that UHR individuals from ethnic minorities presented with more negative symptoms and depression (Velthorst et al., 2009). Adversity in early life, specifically the experience of childhood sexual trauma, has been demonstrated to be associated with an increased risk of transition to psychotic disorders in the UHR population (Thompson et al., 2014).
The continuum model, which proposes that psychosis exists on a continuum throughout the general population, has gained substantial support, with a prevalence of psychotic like experiences in non-clinical general population samples of approximately 5% (van Os et al., 2009). Interestingly, the social environmental risk factors for psychotic disorders, such as ethnicity, social disadvantage, urbanity and low socioeconomic status, are also risk factors for psychotic like experiences in the general population (van Os et al., 2000, Johns et al., 2002, Scott et al., 2006, Morgan et al., 2009). It appears that the risk factors for psychosis and schizophrenia mirror some of the risk factors for the prevalence of psychotic-like experiences in the general population. This highlights the importance of establishing at what point in the illness trajectory the social environmental factors influence the disorder. Establishing whether social environmental risk factors are associated with transition to a psychotic disorder in the UHR population could lead to valuable insights into the aetiology of psychotic disorders.
In this study, we firstly aimed to determine whether the level of social deprivation at the time of presentation was associated with an increased risk of transition to a psychotic disorder. Secondly, we aimed to investigate whether migration status was associated with an increased risk of transitioning to a psychotic disorder.
Section snippets
Setting
The Personal Assessment and Crisis Evaluation (PACE) service is a specialised clinic for individuals assessed to be at Ultra-High Risk (UHR) for psychosis. It is one of the clinics of Orygen Youth Health, a specific youth mental health service for people aged between 15 and 25 years. Orygen Youth Health serves a catchment area of approximately 850,000 people in the inner, mid, north and south Western regions of Melbourne.
Participants
The PACE clinic accepts young people between the ages of 15 and 25 who
Participants
In the study period, there were 219 individuals at UHR of psychosis who participated in research studies in the PACE clinic and of these, 42.5% (N = 93) were male and the mean age at the time of presentation was 18.8 years (S.D. 3.0). The demographic and clinical characteristics of participants are displayed in Table 2. A total of 67.6% (N = 148) had follow-up interviews and 10.5% (N = 23) were followed up by phone interviews and 0.9% (N = 2) by written correspondence and 0.5% (N = 1) had died. The median
Summary of findings
The main findings of this study are the level of social deprivation according to the area of residence and migration status did not appear to influence the risk of transition in a UHR cohort.
Social deprivation
As far back as 1939, it was identified by Faris and Dunham in Chicago that there were higher rates of schizophrenia in the more socially disadvantaged areas (Faris and Dunham, 1939). The finding of a higher incidence of psychotic disorders in areas of higher levels of social deprivation has been replicated
Role of funding source
Dr Nelson was supported by a National Health and Medical Research Council (NHMRC) Career Development Fellowship (1027532), Dr Wood was supported by an NHMRC Clinical Career Developmental Award (359223) and Prof Yung was supported by an NHMRC Senior Research Fellowship (566593). The authors also acknowledge the funding support of the NHMRC Programme grant nos. 350241 and 566529 and the Colonial Foundation. These organisations had no further role in the study design, in the collection, analysis
Contributors
Dr. Brian O’Donoghue developed the idea for the manuscript and was responsible for the writing of the article. A/Prof Barnaby Nelson and A/Prof Andrew Thompson supervised this project. Hok Pan Yuen provided statistical support for the research. All authors contributed to and approved the final manuscript.
Conflict of interest
The authors have no conflicts of interest to declare.
Acknowledgements
The authors are grateful to Sophie Butler and Emily Li for collating data relating to the postcodes of the area of residence.
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2019, Schizophrenia ResearchCitation Excerpt :Therefore, it is generally accepted that biological traits such as genes interact with environmental factors during one's life until a certain threshold is achieved, leading to the first episode of psychosis after a years-long prodromal phase (van Os et al., 2009). To further investigate the risk of conversion, several environmental factors related to psychotic disorders have been studied in UHR populations, such as migration (O'Donoghue et al., 2015), urbanicity (Dragt et al., 2011), and socioeconomic class (Loch et al., 2017), for instance. On the other hand, religion, a factor also related to psychosis in a variety of ways, appears underobserved in UHR studies.
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2015, Schizophrenia ResearchCitation Excerpt :The majority of research to date has focussed on the time of presentation of the first episode of psychosis and therefore the stage of development of the psychotic disorder in which these factors influence the risk of psychosis is unknown. It has been found that the level of social deprivation and migrant status do not influence the risk of transition in a cohort of Ultra High Risk (UHR) for psychosis individuals (O'Donoghue et al., 2015). This suggests that these environmental risk factors could exert their influence early in the aetiology of psychotic disorders, even before identification as UHR by clinical services.
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2015, Schizophrenia ResearchCitation Excerpt :Substance dependence, not abuse, was an exclusion criterion, although substance use can be a coping mechanism in response to stress in this population. Transition rates were low, although similar to recent studies (Fusar-Poli et al., 2012; O'Donoghue et al., 2015). Dropout rates were high; however, multiple imputation estimates confirmed the complete case analyses and dropouts did not differ from completers with respect to baseline characteristics, suggesting that dropouts did not bias our results.