There is a complex interplay between psychological states and biochemical factors.  -Adrenergic receptor responsiveness is altered in some patients with depression and anxiety disorders, but the relation between various psychological states and receptor function in a normal population is unknown. We measured lymphocyte  -adrenergic receptor density (B max ), sensitivity (cAMP ratio), the Profile of Mood States (POMS), and Spielberger State-TraitThere is a strong interplay between psychological states and physiology. This interplay has traditionally been studied extensively in terms of hormonal levels. More recently, investigators have begun to explain how such factors relate to receptor physiology.  -Adrenergic receptor responsiveness may be altered in patients with such psychiatric diseases as depression (Pandey et al. 1987;Magliozzi et al. 1989) and panic disorder (Nesse et al. 1984;Brown et al. 1988;Aronson et al. 1989). In panic disorder, reduced  -adrenergic receptor responsiveness has been noted in two ways, with both reduced receptor density and reduced responsivity to isoproterenol (Maddock et al. 1993).Adrenergic receptor regulation is closely related to psychological stressors (Graafsma et al. 1989).  -Adrenergic receptor function is closely affected by numerous psychological stressors; for example, individuals with high life stress have lower  -adrenergic receptor sensitivity (Dimsdale et al. 1994). Recently, hostility has been shown to be associated with  -adrenergic receptor down-regulation in healthy young males (Suarez et al. 1997). All of these studies suggest that adrenergic receptors may be regarded as an important link between humoral signals influenced by psychological stressors and end organ responsiveness. However, normative information still needs to be acquired concerning the relationship between various psychological states and  -adrenergic receptor responsiveness in a nonpsychiatric population.Human leukocytes offer a useful model for studying the role of  -adrenergic receptor responsiveness in patients with medical or psychiatric illness (Pandey et al. . The use of lymphocyte  -adrenergic receptors as a model for central  -receptors is not as well established as the use of lymphocyte  -receptors for such peripheral tissues as the heart and lung. Nonetheless, Mann et al. (1990) reported a normalization of blunted lymphocyte  -receptors in depression following treatment. In addition, Brodde et al. (1986) reported that alterations in lymphocyte  -adrenoceptors mirror changes in  -adrenoceptors in other tissues less accessible in human studies. There are two major techniques for measuring  -adrenergic receptor responsiveness in human leukocytes; measuring receptor density (B max ) and sensitivity.  -Adrenergic receptor density in lymphocytes is defined as the number of receptors/cell for intact cells, and as pico-or femto-moles/mg protein for membranes.  -Adrenergic receptor sensitivity is defined as the efficiency with which agonist binding translates into stimulation...