How Early Stress Permanently Changes Reactions to Later Stress

Two research groups recently examined mechanisms of the well-known association between adversity early in life and psychiatric disorders affected by patient stress.

Wei and colleagues created transgenic mice that could be induced to overexpress forebrain glucocorticoid receptor (GR) only in early life (before weaning), throughout the animal's lifetime, or in adulthood (after weaning). Early-life and lifetime but not adult groups had anxiety-like behavior and cocaine sensitization (i.e., increased locomotor activity). Early-life and lifetime GR overexpression altered the expression of 4500 genes in the dentate gyrus of the hippocampus; the two groups shared 62% of these changes. Conversely, 71% and 85% of genes with altered expression in the …