The biological function of the SNPs related to the p-factor and neuroticism was examined using DEPICT.30 Table 1 presents the number of enriched gene sets, prioritized genes, and enriched tissues and cell types across the univariate statistics and common factors (Supplementary Tables 10–18 for detailed output). Common factors produced more informative results than the individual indicators. As expected, all of the tissue enrichment for the common factors was identified in the nervous system (Supplementary Figure 22). Neuroticism prioritized genes indicated a central role of synaptic activity (e.g., STX1B, NR4A2, PCLO), including glutamatergic neurotransmission (GRM3). The p-factor gene sets were largely characterized by communication between neurons (e.g., “dendrite development”, “dendritic spine”, “abnormal excitatory postsynaptic potential”). Biological annotation of QSNP statistics for neuroticism indicated that genes within the 69 loci related to neuroticism, but not through a single factor, include: GRIA1, a glutamate receptor subunit (i.e. involved in signaling is excitatory neurons) which has previously been related to schizophrenia,31 chronotype,32 and autism;33 and PCDH17, a gene involved in cellular connections in the brain that has been related to intelligence.34
