In this review we discuss the results of studies about the effect of stress, depression, anxiety, social support and various psychosocial treatments on numbers and activity of Natural Killer (NK) cells. In general a suppressive effect is observed among depressive persons and persons who react to stressfull events with feelings of helplessness and anxiety. Lack of social support also seems to engender immunosuppression including NK suppression. Various forms of psychosocial care seem to be able to undo these negative consequences. However, the real clinical relevance of these findings is still a matter of dispute.
