Review of the literature shows that the common syndrome of chronic pain of uncertain origin appears to be perpetuated by central mechanisms. No plausible neurological theory has been proposed. While the alternative concept of chronic pain as a psychogenic disorder has remained a vague entity, there is strong support to view chronic pain as the prime expression of a muted depressive state. This form of masked depression, however, tends to be associated with a number of characteristic traits. Our studies of patients with chronic pain have led to the identification of a well defined psychobiological disorder with characteristic clinical, psychodynamic, biographic, and genetic features. This syndrome is termed the pain-prone disorder and is viewed as a variant of depressive disease. It proves a distinct entity when compared with a group of patients whose pain can be related to a well defined somatic disease. The chronicity of the disorder appears partially related to the practice of protracted, costly, and futile physical procedures, focusing on a phantom peripheral source of the pain-- a practice commonly pursued by patients and physicians. Recognition of the disorder allows for early, rational, and more effective treatment approaches.