The antidepressant effects of tricyclic antidepressants, serotonin-specific reuptake inhibitors, lithium, and ECT are possibly mediated by an attenuation of inhibitory somatodendritic 5-HT1A receptor function, with a subsequent facilitation of 5-HT transmission (3). Elevated plasma cortisol levels, induced by acute stress or administration of hydrocortisone, attenuate somatodendritic 5-HT1A receptor function in both mice and humans, thereby facilitating 5-HT1A neurotransmission in an antidepressant-like manner (4–6). This is in marked contrast to the effects of long-term elevation of corticosteroids, which reduce postsynaptic 5-HT1A receptor numbers, an effect that may promote depression (7). We propose that this attenuation of somatodendritic 5-HT1A receptor function is the basis of the mood-elevating effects produced by hydrocortisone in the study by Dr. DeBattista et al. and illustrates a potential neurobiological basis of resilience in the face of psychosocial stress. Failure of this response, due, for example, to deficient glucocorticoid receptor function, may be central to the development of depressive illness (8).