Methods for prophylactically treating a stress-induced affective disorder or stress-induced psychopathology in a subject are provided. Also provided are methods for inducing and/or enhancing stress resilience in a subject. In certain embodiments, an effective amount, of an antagonist of the glutamate N-methyl-D-aspartate (NMDA) receptor, such as ketamine, or a pharmaceutically acceptable salt or derivative thereof, is administered to a subject prior to a stressor.