Individuals frequently use alcohol and other drugs to regulate negative emotions and other responses to stressors. Rodent addiction models posit that following repeated alcohol or other drug intoxication, compensatory allostatic changes occur in the central nervous system circuits involved in behavioral and emotional response to stressors. A parallel line of basic affective neuroscience research suggests these adaptations are particularly relevant for reactivity to uncertain stressors. In a programmatic series of complementary drug administration and deprivation studies, I use translational paradigms and contemporary psychophysiological measures to test for evidence of these stress neuroadaptations to uncertain stressors in humans. First, I show alcohol reliably dampens non-addicted individuals’ subcortically-mediated defensive reactivity (startle potentiation), subjective anxiety (self-report) and emotionally-motivated attention (probe P3 event related potential) more during uncertain versus certain stressors. In a drug deprivation study, I then show preliminary evidence that recently abstinent addicted individuals display significantly greater defensive reactivity during uncertain than certain stressors relative to controls as predicted by animal models. I discuss how this research can provide new insights for treating the negative impacts of acute and chronic drug use and how it may guide similar efforts with other psychopathology involving maladaptive reactivity to stressors (e.g., pathological anxiety and depression).