-Epigenetic regulation is the process affecting the expression of a gene without affecting the makeup of the gene itself.

-Studies found that maternal deprivation in rats had long lasting effects in the expression of adrenal steroid receptors, making rats exhibit greater stress responses.

-Epigenetic regulation seen in humans: Brains of suicide victims showed epigenetic changes in adrenal steroid receptors only in the cases where the victims suffered from childhood abuse or neglect.