Date of Award
2018
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Psychology
Abstract
Some of the earliest studies of schizophrenia have included observations that cognitive deficits feature prominently in the disorder. Over time, models of schizophrenia development have expanded this idea to note that cognitive deficits actually emerge prior to illness onset and could confer incremental risk in addition to genetic and environmental insults. As such, these deficits may be thought of as an indicator of schizophrenia liability. This concept relates to the theoretical models informing the current study. The first is that of the endophenotype, which was first fully described by Gottesman and Gould (2003). The endophenotype is an indicator of genetic liability for a given disorder that must be state-independent, occur in genetic relatives as well as individuals with the disorder, be associated with the disorder, and occur more affected individuals than in the general population. The second concept employed in this study is that of the schizotype, as informed by Meehl (1962), which allows that individuals in the general population might be identified using laboratory measures as being in possession of genetic liability to schizophrenia. The current study sought to explore the utility of the antisaccade eye-tracking deficit, a variable conceptually related to executive function, as an endophenotype of schizophrenia by examining performance on this measure in psychometrically identified schizotypes. Forty-four undergraduates were assigned to either a high-schizotypy ( n = 22) or low-schizotypy ( n = 22) group using a matched-control technique and the Chapman Psychosis Proneness Scales (CPPS) to determine group membership. Participants completed an antisaccade eye-tracking task as well as computerized tests of working memory and executive function. A multivariate general linear model comparing mean latency, error latency, and errors between the groups was not significant, nor were univariate analyses of these variables using significance cutoffs of p < .05. However, the error variable produced several robust correlations with executive function measures, across the complete sample and within high- and low-schizotypy groups. A second set of analyses was conducted with high-schizotypy ( n = 33) and low-schizotypy ( n = 28) individuals that included participants for whom a matched pair could not be obtained. This set of analyses yielded the same pattern of results as did the first set. These results did not support the utility of the antisaccade deficit as an endophenotype of schizophrenia, but provided evidence that antisaccade tasks may be used as a measure of the inhibitory component of executive function.
Recommended Citation
Smith, Elizabeth A., "The Antisaccade Eye-Tracking Deficit As An Endophenotype Of Schizophrenia: Results From A Hypothetically Psychosis-Prone Sample" (2018). All-Inclusive List of Electronic Theses and Dissertations. 1735.
https://scholars.indianastate.edu/etds/1735