Narcissistic leaders in groups are capable of impeding progress of their patients and, at worst, can produce iatrogenic effects. Significant interferences may occur when the therapists are unable to tolerate the expression of negative transferences and when they need to be idealized by their patients. The rare therapist who is a malignant narcissist is capable of inflicting severe damage by sadistically exploiting the group to satisfy his own pathological needs. Less severe interferences consist of inhibition in making transference interpretations, reluctance to seek out training or supervision, and a difficulty in protecting patients against being scapegoated. All therapists have some degree of proneness to these problems although hopefully to a minimal degree.