T73. COGNITIVE CLUSTERING IN SCHIZOPHRENIA SPECTRUM DISORDER AND THE ASSOCIATION WITH BRAIN VOLUME

BACKGROUND: Cognitive impairment is a core feature of schizophrenia spectrum disorder (SSD), and appears in both mild and severe forms. As cognition is crucial for functioning in daily life, it is important to understand these impairments. Large heterogeneity exists within these cognitive impairments, and different cognitive profiles may be associated with dissimilar structural brain volumes. Such cognitive brain profiles may be relevant biomarkers for more homogeneous subclasses to be used for both prognosis and choice of optimal care. METHODS: The population consisted of 85 individuals with schizophrenia spectrum disorder (mean age 27 years, 64 males) and 40 healthy controls (mean age 24 years, 31 males). To identify cognitive clusters, hierarchical clustering analyses were conducted using performance on the Brief Assessment of Cognition in Schizophrenia (BACS) battery. The emerging cognitive clusters were compared in performance on the BACS, diagnosis and whole brain volume. RESULTS: Hierarchical clustering analyses revealed three cognitive profiles: cluster 1 “relatively intact” cluster 2 “mild-moderate impairment” and cluster 3 “severe impairment”. Cluster 1 comprised of 68% healthy controls vs 32% SSD patients, whereas clusters 3 comprised of 89% SSD patients vs 11% healthy controls. Cluster 2 was a rather mixed cluster with 25% healthy controls and 75% SSD patients. Whole brain volume shows a continuum towards smaller brain volume in the more impaired clusters with a significant difference shown in whole brain volume between cluster 1 and 3. DISCUSSION: These findings support the concept that cognitive heterogeneity among individuals with schizophrenia spectrum disorder can be reduced by using cognitive clustering methods. Furthermore, cognitive clusters are associated with brain volume sizes, indicating different underlying brain structure. Future research should focus on the predictive power of such clusters.