INS and nicotine dependence: Surprisingly, no pathway was significantly enriched in E_vs_C (p > 0.05), but in the case of Q_vs_C and QE_vs_C, 5 pathways (ubiquinone and other terpenoid–quinone biosynthesis, regulation of actin cytoskeleton, insulin secretion, pancreatic secretion, and nicotine addiction) and 1 pathway (metabolism of xenobiotics by cytochrome P450) were significantly enriched (p < 0.05).