to them, thus the SNP score’s effect is moderated not by developmental neurological or biological maturation, but by a developmentally-confounded environment (i.e., development serves as a proxy for environmental change). Add to this the extra complication that individuals with riskier genotypes are more likely to have biological parents with riskier genotypes, who will smoke more than those who do not (i.e., gene-environment correlation (Jaffee & Price, 2007)), and one can appreciate the challenges we face in understanding how genes and environment affect the development of addiction.
