NPS and nicotine dependence: Gene functional enrichment analysis showed that the genes involved in CO events were mainly enriched in the pathways of Neuroactive ligand-receptor interaction, Nicotine addiction, Morphine addiction, cAMP signaling, Calcium signaling and the biological processes of chemical synaptic transmission, cell adhesion, neuropeptide signaling pathway and so on (Figure 2B and Supplementary Table S2).