Neighborhood-level predictors of age at onset and duration of untreated psychosis in first-episode psychotic disorders

Abstract

Objective

Recent years have witnessed growing interest in the role of the social environment in the development and outcomes of schizophrenia. We investigated whether neighborhood characteristics are associated with two important prognostic factors in early-course psychosis, age at onset of psychosis (AOP) and duration of untreated psychosis (DUP).

Methods

Data were collected from patients admitted to the hospital for first-episode schizophrenia-spectrum disorder. We collected data on perceived neighborhood disorder during childhood/adolescence and extracted data on 13 neighborhood characteristics from the American Community Survey based upon individual addresses. Four neighborhood-level factors were derived from factor analysis. Multiple logistic regression analyses assessed the association between specific neighborhood characteristics and the two prognostic factors (earlier AOP and longer DUP) in early-course psychosis.

Results

143 participants had valid addresses geo-coded. Neighborhood-level residential instability was associated with an earlier AOP (OR = 1.760; p = 0.022) even after controlling for known risk factors (OR = 2.026; p = 0.020) and also after controlling for individual-level residential instability (OR = 1.917; p = 0.037). The general socioeconomic status neighborhood factor (OR = 1.119; p = 0.019) and perceived neighborhood disorder (OR = 1.075; p = 0.005) were associated with a longer DUP. But only perceived neighborhood disorder (OR = 1.146; p = 0.011) remained significant, and general socioeconomic status was close to significant (OR = 1.215; p = 0.062), after controlling for individual-level predictors and socioeconomic status.

Conclusions

This study found evidence that neighborhood-level characteristics (in this case, residential instability) may be associated with earlier AOP, and perceptions of neighborhood disorder are associated with a longer treatment delay. Socioenvironmental factors should be more consistently considered going forward in research on early psychotic disorders.

Introduction

Neighborhood characteristics are known to be important social determinants of health, influencing a wide range of outcomes related to chronic physical illnesses such as obesity and diabetes (Ludwig et al., 2011). Growing evidence suggests that neighborhood characteristics influence the rates and outcomes of mental illnesses as well, including schizophrenia (Eaton et al., 2019; Heinz et al., 2013; Kirkbride et al., 2014). Though sparsely studied in the United States, this association was first explored >80 years ago when Faris and Dunham (1939) demonstrated an association between high rates of schizophrenia and city zones in Chicago characterized by social disorder or lack of cohesion. They argued that those who resided in disorganized communities found it difficult to foster and maintain positive affiliations with local institutions, neighbors, and family members, thus increasing these residents' sense of social isolation, which was deemed significant to the onset and course of mental illnesses (Faris and Dunham, 1939). Some recent research suggests that neighborhood characteristics may influence rates of schizophrenia. Specifically, more population-dense areas and areas with lower socioeconomic status may have higher incidence rates of psychosis (Heinz et al., 2013; Kirkbride et al., 2014; Richardson et al., 2018). In addition, a few studies have assessed neighborhood variation in relation to prognostic factors and positive symptoms (Kirkbride et al., 2010; Newbury et al., 2016). However, in the United States, there has been a dearth of research to characterize the relationship between specific neighborhood factors and key manifestations of schizophrenia and related psychotic disorders.

An earlier age at onset of psychosis (AOP) and longer duration of untreated psychosis (DUP) are two important factors associated with poorer prognosis for schizophrenia (e.g., greater symptom severity, longer time to and less likelihood of remission). Known risk factors for earlier AOP, one of the most commonly examined predictors of outcomes in schizophrenia (Clemmensen et al., 2012; Hafner et al., 1998; Immonen et al., 2017), include family history of psychosis (Suvisaari et al., 1998), male gender (Gureje, 1991; Hafner et al., 1998), and earlier age at initiation and more rapid escalation of premorbid cannabis use (Arseneault et al., 2002; Compton et al., 2009b; Kelley et al., 2016; McGrath et al., 2010; Stefanis et al., 2013; Zammit et al., 2002). Longer DUP is associated with poorer response to treatment, more frequent relapses, and poorer long-term symptom and functioning outcomes (Marshall et al., 2005; Perkins et al., 2005). Conversely, early detection of and intervention for psychosis considerably improves outcomes (Burns, 2013). Risk factors for longer DUP include chronic or insidious mode of onset of psychosis (Compton et al., 2008; Larsen et al., 1996; Morgan et al., 2006), history of incarceration (Broussard et al., 2013), and possibly cannabis use (Broussard et al., 2013; Burns, 2012).

Given the significance of AOP and DUP to the prognosis of schizophrenia, identifying other modifiable risk factors shaping them could ultimately inform means of improving outcomes. Exploring whether neighborhood characteristics in adolescence affect AOP and DUP could have a public health impact by leading to population-level interventions to influence the rate and course of psychotic disorders (and at the same time, many other illnesses and health outcomes).

To further explore the relationship between neighborhood characteristics and prognostic factors in early-course psychotic disorders, this analysis investigated the following questions: (1) Which neighborhood-level characteristics (both subjectively rated and objectively obtained), if any, are associated with AOP and DUP? (2) Do any potential effects of neighborhood-level characteristics on these prognostic factors remain after controlling for known risk factors for AOP and DUP? (3) Do the potential effects of neighborhood-level characteristics on these prognostic factors remain after controlling for individual-level sociodemographic characteristics? This study builds on the well-established link of urbanicity and neighborhood adversity with psychosis by examining the association of several neighborhood characteristics with AOP and DUP.

There have only been two studies investigating the relationship between neighborhood characteristics and DUP, in Southeast London and South Dublin (Kirkbride et al., 2010; O'Donoghue et al., 2016), which found conflicting results. While one study did not find variability in DUP across neighborhoods in Southeast London (Kirkbride et al., 2010), another reported that the least socially fragmented neighborhoods in South Dublin had very short DUPs (O'Donoghue et al., 2016). This is the first study in the United States, to our knowledge, to study the relationship between neighborhood characteristics and two prognostic factors: AOP and DUP. As such, we made no a priori hypotheses regarding the relationships between specific neighborhood characteristics and AOP or DUP. Based on prior literature examining the relationship between neighborhood characteristics and other health outcomes in the United States (Alegría et al., 2014; Krieger et al., 2002; Silver et al., 2002), we employed both objective (i.e., those obtained from census-tract data) and subjective (based on self-reported perceptions) measures of neighborhood characteristics to explore possible associations with AOP and DUP.