Figure 4. Individual addiction vulnerability.
High and low risk for developing substance use disorders is determined by a complex interaction of (A) genetic/molecular factors (e.g. genetic variants affecting microRNA binding and epigenetic regulation of gene expression), (B) neural pathways (e.g. changes in direct and indirect striatal pathway activity), (C) behavioral endophenotypes (e.g. heightened impulsivity and novelty seeking), and environmental factors. SNP: single nucleotide polymorphism, 3′UTR: 3′ untranslated region, miRNA: microRNA.