Environmental factors and social adjustment as predictors of a first psychosis in subjects at ultra high risk

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Abstract

Background

The onset of schizophrenia is associated with genetic, symptomatic, social and environmental risk factors. The aim of the present study was to determine which environmental factors may contribute to a prediction of a first psychotic episode in subjects at Ultra High Risk (UHR) for developing psychosis.

Method

We included 72 UHR subjects and followed them over a period of 36 months, of whom nineteen (26.4%) made a transition to psychosis. We applied survival analyses to determine associations between a transition to psychosis and environmental factors and social adjustment. To determine which items are the best predictors of transition to a first psychotic episode, Cox Regression analyses were applied.

Results

Urbanicity, receiving state benefits and poor premorbid adjustment (PMA) significantly influenced the transition to psychosis. Urbanicity (Wald = 10.096, p = .001, HR = 30.97), social–sexual aspects (Wald = 8.795, p = .003, HR = 1.91) and social–personal adjustment (Wald = 10.794, p = .001, HR = 4.26) appeared to be predictors for developing psychosis in our UHR group.

Conclusions

Environmental characteristics and social adjustment are predictive of transition to a psychosis in subjects at UHR. These characteristics should be implemented in a model for prediction of psychosis. Such a model would be more specific than current models and may lead to patient-specific preventive interventions.

Introduction

Schizophrenia and related psychoses are severe, mostly lifelong disorders with an onset in adolescence and young adulthood and with high morbidity and mortality (McGrath et al., 2008). The symptoms and signs before the first psychotic episode—during the so-called prodromal phase—are not well defined, precluding the possibility of predicting the onset of a first psychotic episode. If we can identify risk factors for developing psychosis better, we may be able to shorten, delay or even to prevent a first psychotic episode.

The prodroma\l phase is characterized by various mental state features, including nonspecific symptoms such as depressed mood and anxiety as well as sub threshold or attenuated psychotic symptoms. The prodromal period is found to be highly variable in length: it ranges from a few days to a period with a duration of many years (McGorry et al., 1995, Yung and McGorry, 1996). A mean duration of 4.8 years has been reported (Häfner and Maurer, 2006). Since the prodromal stage can only be determined retrospectively, putatively prodromal subjects are referred to as ultra high risk (UHR).

The distinction of an UHR group turned out to be a partially successful for psychosis prediction. Belonging to one of these groups predicts psychosis after one year in 12–50% of the people with an UHR state (Yung et al., 2007). Limitations of these initial studies were the small numbers of included individuals at risk, the large number of false positive inclusions in these studies and the short duration of the follow-up period. Therefore it can be useful to look at additional factors that help predict onset of psychoses in vulnerable individuals.

Increasing knowledge on risk factors for schizophrenia recognized gene–environment interactions as important ingredients. A meta-analysis of ten studies shows that approximately 30% of all schizophrenia incidences may be related to growing up and living in an urban environment (Krabbendam and van Os, 2005). This implies that urbanicity may be the strongest risk factor of all environmental factors for schizophrenia and related psychotic disorders. In addition to urbanicity, four other environmental risk factors have been described in a review by Os van et al. (2005). These include: cannabis, minority status, early trauma and prenatal and early childhood exposures. Prenatal and early childhood environmental effects could be folate or vitamin D deficiency, viral infections or adverse effects associated with high or low birth weight. A recent study suggests that unemployment, social isolation, reduced employment achievement and expectations are also associated with the risk of psychosis (Reininghaus et al., 2008). Poor premorbid adjustment in schizophrenia is associated with worse prognosis of the disease (Rabinowitz et al., 2005, Rabinowitz et al., 2006, Haim et al., 2006). Also premorbid adjustment, as assessed with the Premorbid Adjustment Scale-PAS (Cannon-Spoor et al., 1982) is suggested to be a valuable phenotype characteristic in schizophrenia development (Schmael et al., 2007). Shapiro et al. (2009) found that both patients and their siblings shared poor adjustment in childhood and adolescence. Possibly this could be due to shared genetic or environmental risk factors.

Based on environmental factors and premorbid social adjustment characteristics found or suggested to be risk factors by previous researchers, we investigated their associations with transition to psychosis in subjects already at UHR for developing psychosis. We wanted to investigate if these environmental factors and premorbid social adjustment characteristics were associated with transition to psychosis independently of baseline clinical symptomatology as described by Velthorst et al. (2009). Specifically, we hypothesized that UHR subjects with the following characteristics; urbanicity, unemployment, receiving state benefits, ethnicity, head trauma, complications during intrauterine development or birth complications and with poorer premorbid social adjustment were more likely to make a transition to psychosis than those without.

Section snippets

Methods

The present study, a naturalistic study with its major focus on the course of UHR symptomatology, took place at the Amsterdam site of the “Dutch Prediction of Psychosis Study (DUPS)”. Between August 2001 and July 2009 data were collected. Our sample is similar to the sample used by Velthorst et al. (2009).

General characteristics

From the 285 adolescents and young adults referred to our hospital at the time of this study, 74 met the inclusion criteria of ultra high risk and gave their consent after having been informed about the study. Two participants were not assessed with all questionnaires. Therefore 72 participants were included for analysis. General characteristics are summarized in Table 1.

Transition rate

19 (26.4%) of the 72 included participants made the transition to psychosis. The mean interval between inclusion and

Discussion

In this prospective long term study we replicated recent findings that social adaptation in early adolescence, social personal adjustment in general and lower highest level of functioning achieved in life are predictive for a first psychosis. Cannon et al. (2008) found that greater social impairment increased the risk of developing psychosis in a UHR sample. Velthorst et al. (2009) reported that social anhedonia and withdrawal at baseline were predictive for a first psychotic episode in

Role of the funding source

This study was supported by a grant for the Dutch Prediction of Psychosis Study from ZON-MW (ZorgOnderzoek Nederland/NWO-Medische Wetenschappen, project # 2630.0001) and a grant from the European Commission in Brussels, Belgium for the European Prediction of Psychosis study (grant QLGU-CT-2001-01081). ZON-MW and the European Commission had no further role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the

Contributors

Author Dorien Nieman was involved in the design of the study, statistical analysis and wrote part of the first draft of the manuscript. Doede Veltman was involved in the statistical analysis and wrote parts of the first draft of the manuscript as an assignment for his internship at our department. Hiske Becker included patients in the study and did clinical assessments concerning transition to psychosis. Reinaud van de Fliert recruited patients into the study and did clinical assessments.

Conflict of interest

All authors declare that they have no conflicts of interest.

Acknowledgements

We thank Ed Hull for the grammatical and textual check of the first draft of our manuscript. We thank Arnold Ziegelaar for his help with the analysis of the data.

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