Differential Associations of Negative Symptom Dimensions with Cognition and Decision-making

Abstract

Introduction

Negative symptoms show a modest association with dysfunctions in cognition and decision-making. Recently, a consensus has emerged that negative symptoms can be divided into the dimensions apathy and diminished expression, but there is still limited evidence for a differential association of these dimensions with cognition and decision-making.

Objectives

We conducted two studies to investigate whether apathy and diminished expression are differentially associated with cognitive and motivational processes in patients with schizophrenia.

Methods

Apathy and diminished expression were assessed with the Brief Negative Symptom Scale. In study 1 50 patients completed a cognitive test battery. In study 2 31 patients performed an effort-based decision making task assessing the willingness to work for a reward. They also performed an option generation task assessing the ability to generate options for actions in ill-structured situations.

Results

In study 1 no significant association of either negative symptom association with a composite cognitive score was observed. A strong negative association was found between diminished expression and verbal learning. In study 2 apathy was strongly and specifically associated with increased effort discounting, i.e. apathetic patients were less willing to work for a reward. Patients also showed a reduction in the quantity of options for action generated in ill-structured decision situations.

Conclusions

We provide evidence for a differential association of cognitive and motivational processes with dimensions of negative symptoms. Diminished expression is associated with cognitive dysfunction, specifically verbal memory performance. In contrast, apathy is associated with specific motivational and cognitive processes underlying decision-making in patients with schizophrenia.