Our pathway analyses identified multiple pathways shared by schizophrenia and ND. The most significant pathways were Calcium Signaling, Long-Term Potentiation and Neuroactive Ligand-Receptor Interaction. These pathways are involved in neurotransmitter transduction and communication between neurons, and they are essential for cognitive functions. These pathways have been shown to be involved in schizophrenia284344 and ND4546. The Cell Adhesion Molecules and Regulation of Actin Cytoskeleton pathways have also been reported in schizophrenia31474849 and ND455051. Thus, our results are consistent with these studies. It is worth noting that the cardiomyopathy pathways were identified in our analyses and that, in a previous study, we found that CMYA5 was associated with schizophrenia52. Another gene, NDUFV2, causative to hypertrophic cardiomyopathy5354, the genetic form of cardiomyopathy, was also found to be associated with schizophrenia555657. Pathway crosstalk analyses showed that many of these pathways interact with each other and together they form an interlinked network with the Long-Term Potentiation pathway at the center of these interactions. In animal studies, nicotine alters long-term potentiation585960 and learning and memory61. In humans, smoking may alleviate cognitive impairment62, and both nicotine withdrawal
