The neural correlates of apathy in schizophrenia: An exploratory investigation

Motivational deficits represent a core negative symptom in patients with schizophrenia. Previous morphology studies have demonstrated that apathy in patients with schizophrenia is associated with reduced frontal grey matter (GM). We attempted to replicate this previous finding, and explored whether it was distinct from potential associations with a distinct subdomain of negative symptoms, namely Affective Flattening, and GM.

Twenty medicated patients with schizophrenia provided structural T1-weighted images acquired on a 3-Tesla MRI scanner and negative symptoms were evaluated using the Scale for the Assessment of Negative Symptoms. Voxel-based morphometry (VBM) was used to explore the correlations between whole-brain GM and i) Apathy, and ii) Affective Flattening, respectively.

Apathy scores were negatively correlated with several GM clusters in frontal regions, including the frontal inferior operculum and the left dorsal anterior cingulate cortex. Only positive correlations with GM clusters were observed for Affective Flattening, particularly in the inferior temporal lobe. Notably, the regions associated with apathy scores were distinct from those associated with Affective Flattening, and these findings remained after controlling for antipsychotic medication dosage.

We replicated previous associations between reduced frontal GM and apathy in patients with schizophrenia. Moreover, we demonstrated that these GM associations are distinct from those with Affective Flattening. The present findings set the stage for future larger-scale studies confirming the structural and neurochemical substrates of apathy in schizophrenia.