Elsevier

Journal of Psychiatric Research

Volume 94, November 2017, Pages 180-185
Journal of Psychiatric Research

Health status and mobility limitations are associated with residential and employment status in schizophrenia and bipolar disorder

https://doi.org/10.1016/j.jpsychires.2017.07.011Get rights and content

Abstract

Introduction

Schizophrenia (SCZ) and bipolar disorder (BP) are linked to multiple impairments in everyday functioning which share cognitive and symptom risk factors. Other risk factors for critical aspects of every day functioning (e.g., gainful employment; residential independence) such as physical health have not been evaluated, despite poor health in SCZ and BP.

Methods

We analyzed 20-year follow-up data from the Suffolk County Mental Health Project cohort of consecutive first admissions with a psychotic disorder to 12 psychiatric facilities in Suffolk County, NY, between September 1989 and December 1995. Both 20-year symptom, health, and cognition data, and the 20-year course of weight gain were included as predictors of employment and residence status.

Results

The analysis sample consisted of 122 participants with SCZ ad BP, with SCZ participants less likely to work or live independently. Correlational analyses showed symptoms and cognition predicted vocational outcomes in both samples. The effect of diagnosis was significant for both gainful employment and independence in residence. After consideration of diagnosis, mobility and negative symptoms predicted gainful employment in both samples, but there were no additional predictors of residential independence. Prospective analysis of BMI found that baseline BMI, but not changes during the 20-year follow up, predicted labor force participation.

Discussion

Health status limitations were associated with residential and, particularly, employment status independent from other, previously established predictors of everyday outcomes, including cognition and symptoms. The importance of health status limitations for predicting outcome was confirmed in both SCZ and BP, with schizophrenia representing the more impaired group.

Introduction

Severe and persistent mental illnesses (SPMI), including schizophrenia (SCZ) and bipolar disorder (BP), are associated with high rates of disability in the US and worldwide (Kim et al., 2010, Murray et al., 2013, Whiteford et al., 2010). Despite the striking nature of psychotic and manic symptoms, the costliest impairments include wide-ranging limitations in critical areas of daily functioning, particularly in the ability to live and work independently (Huxley and Baldessarini, 2007, McEvoy, 2007, Jin and McCrone, 2015), which is lower than population norms (Harvey, 2009, Harvey et al., 2010).

Disability is a complex construct attributable to a cascade of multiple interdependent influences. In SPMI, known determinants of disability include cognitive deficits, which are indexed by performance on neuropsychological tests, and other specific symptoms (e.g., enduring negative symptoms, treatment refractory psychosis, or recurrent episodes of mania or depression). However, even in combination with impairments in performance-based measures of functional capacity (“skills deficits”), these predictors account for less than 50% of the total variance, suggesting that other, unexplored factors contribute to the high rates of disability in SPMI (Bowie et al., 2006, Bowie et al., 2008, Bowie et al., 2010).

Previous studies of BP and SCZ have found that predictors of daily functional outcomes are similar in the two patient populations (Bowie et al., 2010, Mausbach et al., 2010). However, when compared to BP patients, individuals with SCZ have poorer residential outcomes and performance on measures of daily living skills, lower educational achievement, and greater impairment in clinician ratings of everyday outcomes (Mausbach et al., 2010, Meyer et al., 2014, Velthorst et al., 2016). These cross-diagnostic relative levels of impairments hold across different countries and cultures (McIntosh et al., 2011), although the correlations between skills deficits and outcomes seems quite consistent on a cross-national basis.

Given the high prevalence of obesity (De Hert et al., 2009, Allison et al., 2009, Fagiolini et al., 2008) and poor physical functioning in individuals with SPMI (Vancampfort et al., 2017, Strassnig et al., 2014), we hypothesized that physical health limitations may have an even greater influence on disability in SPMI groups than in mentally healthy individuals (Scott et al., 2009) (Fig. 1). Individuals with SPMI often have a poor diet, are sedentary, engage in little or no physical exercise, and are persistent smokers (Newcomer and Hennekens, 2007), and these risk factors are exacerbated by cognitive deficits and clinical symptoms (Harvey and Strassnig, 2012), as well as chronic treatment with sedating and obesogenic psychotropic medications.

We know of no studies of the SPMI population that have examined the relationships of obesity and physical functioning, together with cognitive impairments and clinical symptom severity, to the ability to live independently or sustain employment. In this paper, we examine these relationships using data from a well-characterized sample that was followed for 20 years after first hospitalization for a psychotic episode. We also used these data to assess whether people with BP and SCZ show similar associations between clinical, cognitive, and physical variables and daily functioning.

Section snippets

Methods

All participants provided written informed consent at the initial and subsequent assessments. Inclusion criteria were age 15–60 years, residence in Suffolk County NY, and psychosis not due to a medical condition. Exclusion criteria were a psychiatric hospitalization more than 6 months before the index admission, more than borderline intellectual disability (IQ < 70), inability to provide informed consent, and being a non-English speaker. The data were collected at 6 months, and 2, 4, 10, and 20

Results

The final sample included 128 patients with complete data (80 SCZ; 48 BP). Mean age at the 20-year assessment was 47.8 ± 8.6, and 54.2% were male. 62.7% had a diagnosis of schizophrenia or schizoaffective disorder and 37.3% of BP. Participants included 2.6% Asian, 9.4% African American, and 78.5% white, with 9.4% other/unknown, reflecting local population characteristics. In the entire sample, 32.9% were employed, and 53.9% maintained independent residence at the 20-year assessment. There were

Discussion

We show that health status limitations, recognized recently as pervasive in severe mental illness, predicted employment in a manner independent from other correlates established previously, including cognition and symptoms, and the importance of symptoms and physical limitations in predicting employment outcomes was confirmed in both BP and SCZ. In the multivariable models, a different set of factors predicted the two objective outcome parameters (employment, independent residence).

Limitations

The initial BMI measures were obtained at month 6 as opposed to the first contact baseline assessment which had a predominantly diagnostic focus. As a result, we were unable to measure the early impact of weight gain on later functioning and disability during a time period where significant treatment induced weight gain tends to occur. However, we have recently described the weight gain trajectories in this sample (Strassnig et al., 2017) and have found that weight gain in both SCZ and BP

Conflict of interest

Dr. Harvey has received consulting fees or travel reimbursements from Allergan, Boehringer Ingelheim, Lundbeck Pharma, Minerva Pharma, Otsuka Digital Health, Sanofi Pharma, Sunovion Pharma, and Takeda Pharma during the past year. He has a research grant from Takeda 2014 100914 and from the Stanley Medical Research Foundation Grant 151.

Drs. Strassnig, Bromet, Kotov and Fochtmann, and Ms. Cornaccio have no conflict of interest to report.

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