Recent studies have reported an association between exposure to childhood abuse or neglect and alterations in brain structure or function. One limitation of these studies is that they are correlational and do not provide evidence of a cause-effect relationship. Preclinical studies on the effects of exposure to early life stress can demonstrate causality, and can enrich our understanding of the clinical research if we hypothesize that the consequences of early abuse are predominantly mediated through the induction of stress responses. Exposure to early abuse and early stress has each been associated with the emergence of epileptiform electroencephalogram (EEG) abnormalities, alterations in corpus callosum area, and reduced volume or synaptic density of the hippocampus. Further, there is evidence that different brain regions have unique periods when they are maximally sensitive to the effects of early stress. To date, preclinical studies have guided clinical investigations and will continue to provide important insight into studies on molecular mechanisms and gene-environment interactions.