Linking temperamental fearfulness and anxiety symptoms: A behavior-geneticperspective

Research on mood and anxiety disorders has historically proceeded without s ufficient reference to the growing body of work on the nature of typical em otional development and temperament. Reviewing data from several studies, w e consider experiential, biological, and generic factors as providing causa l input to typical developmental variation in fearfulness and anxiety durin g infancy and early childhood. Longitudinal behavioral methods, psychophysi ologic measures, and a behavior-genetic framework are used to approach thes e issues. Results from twin studies implicate moderately strong genetic inf luences on different facets of temperamental fearfulness, as well as childh ood anxiety symptoms. Then, we consider the dis tinction between normal ran ge temperament and overt anxiety symptoms from a quantitative generic persp ective. Biological correlates (cortisol, asymmetric frontal EEG activation cardiac reactivity) of inhibited behavior are considered as I-elated endoph enotypes for anxiety. In a nongenetic analysis, we report the prediction of internalizing problems during kindergarten from earlier temperament and ea rlier basal cortisol measures. Our review highlights connections between be havioral indicators and various putative endophenotypes and the fuzzy bound ary between normal-range temperament and anxiety disorders.. (C) 2000 Socie ty of Biological Psychiatry.