The neurobiological basis of mixed depression-anxiety states.

A recognition of the clinical overlap of symptoms of anxiety disorders and those of affective disorders has brought with it a need to move beyond descriptive definitions of the syndromes to an etiologic and neurobiological understanding of their psychopathology. The authors discuss the neurobiological basis of mixed depression-anxiety states with special attention to the literature on pharmacologic treatment outcome studies, neurotransmitters in anxiety and depression, and the hypothalamic-pituitary-adrenal axis.