Dissertations, Theses, and Capstone Projects

Date of Degree

9-2024

Document Type

Dissertation

Degree Name

Ph.D.

Program

Psychology

Advisor

Deborah J. Walder

Committee Members

Jennifer Ford

Angelo DiBello

Yu Gao

Yvette Caro

Subject Categories

Clinical Psychology | Health Psychology

Keywords

schizotypy, health behaviors, physical health

Abstract

Schizophrenia has consistently been associated with increased rates of physical illness and early mortality. One explanation for this association might be poor health behaviors, as people with schizophrenia are more sedentary, less physically active, and more likely to engage in substance use compared to the general population. Schizotypy may be conceptualized as the phenotypic expression of increased risk for schizophrenia spectrum disorders, and dimensional models of schizotypy suggest that it varies on a continuum ranging from non-clinical (i.e. low schizotypy) to clinical (i.e. high schizotypy and dysfunction, as in schizophrenia). Though schizotypy and schizophrenia appear to share similar deficits and risk factors, few studies have assessed the relationships among schizotypy, physical health, and health behaviors, which may help to clarify the etiology of poor physical health in schizophrenia. Aims of the current study were to: 1) test associations of schizotypy with physical health and with health behaviors, 2) assess whether health behavior profiles moderate the relationships between schizotypy and physical health, and 3) assess whether health behaviors mediate the relationship between schizotypy and physical health. Study participants included 2,319 (72.7% female; Mage = 20.59) young adults from a non-clinical undergraduate sample who completed self-report measures of schizotypy, physical health (self-reported general health, past month unhealthy days, number of physical illnesses, and body mass index), and health behaviors (physical activity, sleep quality, substance use, and preventive care engagement). Linear regressions showed significant relationships of schizotypy with worse physical health (including poorer self-reported general health, more past month unhealthy days, and higher total number of physical illnesses) and poorer health behaviors (including worse sleep quality and increased substance use). Latent profile analyses demonstrated three health behavior profiles: a healthy and engaged group (high physical activity and high preventive care), a healthy and disengaged group (low physical activity and low preventive care), and an elevated risk group (poor sleep quality and increased use of alcohol and tobacco). The elevated risk group had significantly higher levels of schizotypy compared to the other two groups, as well as the poorest self-reported physical health. Contrary to hypotheses, no moderation effect of health behavior profile was demonstrated. Although the hypothesized mediation model did not achieve adequate model fit in structural equation modeling, three mediation models were tested based on model fit statistics and theoretical soundness, and all three models showed no mediation effect of health behavior on schizotypy and physical health. Exploratory analyses of individual health behaviors demonstrated that poor sleep quality partially mediated the relationship between elevated schizotypy and worse self-reported general health. This study adds to the nascent literature suggesting that schizotypy, much like schizophrenia, is associated with poor physical health and poor health behaviors, and provides preliminary evidence that sleep quality may be an important target for clinical interventions designed to reduce the physical health burden among people with increased psychosis risk. Further research is needed to replicate these findings and to clarify moderators and mechanisms among schizotypy, physical health, and health behaviors.

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