Seeing the unexpected: how sex differences in stress responses may provide a new perspective on the manifestation of psychiatric disorders.

In this report, the authors propose that underlying sex differences in the biobehavioral response to stress may contribute to the variance in prevalence of some psychiatric disorders based on sex. The authors begin with a discussion of stress physiology and review a new theory on sex differences in stress responses (ie, the "tend-and-befriend" response), which may provide a recent framework for considering sex differences in the manifestation of some psychiatric illnesses. The authors then move to a discussion of major depression and attention deficit hyperactivity disorder as examples of how sex differences in stress responses may influence the behavioral symptoms of psychiatric disorders that are more often diagnosed in one sex compared with another. The authors conclude with a brief discussion of the implications of this new perspective on treatment approaches and encourage further inquiry into the importance of sex-based differences in the behavioral manifestation of some psychiatric illnesses.