The current study aimed to examine if a schizophrenia PRS was associated with psychopathology symptom and cognitive dimensions in addition to potential candidate associations in a sample of patients with chronic schizophrenia. The biological basis of symptom dimensions and performance in cognitive domains (Glahn et al., 2014) are deemed to be less complex than the schizophrenia phenotype itself and as such we evaluated for overlap with schizophrenia genetic liability. In our chronic sample, we found a significant PRS association with negative symptoms for both models (with and without neurocognition). Model that controlled for the effects of neurocognition explained a significant amount of variance (1.2%) in negative symptoms, though this did not survive permutation testing and could likely be explained by our smaller sample size. PRS associations with negative symptoms have been somewhat inconsistent in the literature with both positive (Jones et al., 2016; Fanous et al., 2012) and negative findings (Sengupta et al., 2017). Such inconsistencies could be a reflection of the heterogeneity of the sample or the sample size itself. PRS prediction accuracies are found to be strongly linked to sample size (Dudbridge, 2013).
