Studies that have examined the molecular basis of symptoms have found genetic evidence for specific symptom dimensions in schizophrenia. Evidence from candidate gene association studies identify the possibility of shared (neurotransmitter systems, neuronal development and maintenance) and unique associations to positive and negative symptom dimensions (Xavier and Vorderstrasse, 2017), though functional mechanisms are still unclear. Polygenic scores for schizophrenia have shown associations with symptom dimensions, though with inconsistencies. PRS correlations are reported in the literature for negative/disorganized dimensions not just in schizophrenia patients (Fanous et al., 2012) but also in adolescents in the general population where it predicted negative and anxiety symptoms (Jones et al., 2016). But a recent study had negative findings and the association of PRS with negative symptoms was not replicated in first episode psychosis; instead a polygenic loading was found for general psychopathology dimension and anxiety symptoms (Sengupta et al., 2017). Though in this study a PRS association with negative symptoms was reported in the Caucasian only sub-group (Sengupta et al., 2017).
