Understanding thought disorder in schizophrenia-spectrum disorders : exploring the relation and implications of affect.

Abstract

The significance of affect in schizophrenia-spectrum disorders has received considerable support, including its role in cognitive processing and executive function. Findings examining affect and cognition in schizophrenia appear to parallel findings with healthy controls: positive affect contributes to broad, top-down processing and negative affect leads to narrow, bottom-up processing. This dissertation extends this exploration to the study of affect and its role in thought disorder, a core, and yet enigmatic feature of schizophrenia-spectrum disorders. This dissertation examines the role of affective intensity and valence in thought disorder severity. Self-reported affective intensity and valence were assessed with the PANAS, and thought disorder severity was evaluated by scoring Rorschach protocols using the Thought Disorder Inventory. The dissertation has two hypotheses: (1) affective intensity is a more significant factor than affective valence in predicting the severity of thought disorder in schizophrenia and schizoaffective disorder, and (2) positive affect is related to categories that reflect broader, more associative processing, while negative affect is related to categories that reflect narrowed processing. Both hypotheses were supported. Affective intensity significantly predicted thought disorder severity and was a better predictor, overall, then affective valence. Furthermore, positive and negative affect were related to indicators of broad versus narrow processing, respectively. Self-reported negative affect emerged as a particularly salient variable in thought disorder severity and presentation. The current findings have implications for our understanding of the mechanisms underlying thought disorder severity in schizophrenia-spectrum disorders, and the significance of affective experience in this spectrum of illness.