Ironically, in spite of the label "affective disorders", research on affective disorders has little to say about just what is disordered about emotion in these illnesses. One major purpose of this Special Issue is to begin to raise this question as a legitimate domain of inquiry in studies of emotion and psychopathology. Historically, the literature on emotion in normal subjects has proceeded almost entirely independently of studies of emotion-related psychopathology. And, studies on psychopathology make virtually no reference to basic research on emotion in normals. Major advances have occurred in our understanding of the neural substrates of these affective processes. Their application to the study of disordered emotion in affective and anxiety disorders is comparatively recent.
A goal of this Special Issue is to foster increased integration between research on the neural mechanisms underlying normal emotion and disordered emotion in depression and anxiety-related illnesses. It features exemplars of the best research at many levels, from animal studies of the detailed circuitry subserving fear and anxiety, to human studies of cognitive abnormalities in subjects with affective and anxiety disorders. It also highlights a myriad array of methods for making inferences about affective processes, ranging from the biological to the behavioral, and from the molecular to the molar. A central concept that figures prominently in this collection of articles is the importance of individual differences in different components of affective processes. The study of the brain circuitry that underlies such differences in affective style offers great promise in providing a biologically plausible way of parsing the affect domain and developing a theoretically compelling taxonomy of mechanisms that give rise to vulnerability to affective and anxiety disorders.