[The psychological aspect of cancer pain.].

The perception and expression of pain are primarily psychological phenomena and are not directly correlated with the intensity of the nociceptive stimulus. They are often influenced by earlier experiences of pain, and also by current expectations and fears. The cancer patient interprets pain as a sign of the continued existence and of the progression of the malignant disease: if the pain can be controlled the patient will take this as an indication that the underlying disease can be cured. Inappropriately treated pain, on the other hand, can initiate a vicious circle leading to really excruciating pain and functional destabilization of the patient. Conversely, the personality and the psychological condition of the patient can have a profound effect on how pain is experienced. Fear, for example, is known to exacerbate pain, and fear is often due to a less than ideal doctor-patient relationship, e.g. one in which the patient does not receive adequate information about the disease. Pain can be interpreted as a message that has to be understood before an adequate therapeutic response is possible. For desperate patients who are socially isolated after a long period of illness, pain may be the only way of communicating their unhappiness to other people and of feeling alive at all. Patients with intractable pain are sometimes given placebo therapy, particularly if the pain is interpreted as "only" psychogenic in character or if traditional methods of treatment have failed. Confrontation with terminally ill patients is an especially difficult and frustrating experience for health professionals. The fact that the disease cannot be cured and that a patient is in constant pain reminds the physician of the limitations of curative medicine. This can trigger defense mechanisms in the physician, which may in turn cause insecurity and fear in the patient. In the course of treatment for pain, cancer patients derive most psychological support from the emotional empathy of the therapist, whose availability for the patient is the most important means of preventing the patient's with-drawal into depression. If cancer pain is accompanied by an emotional, psychic and vegetative imbalance, psychotropic drugs are beneficial. In particular, antidepressants and neuroleptics have become an important component of the treatment of chronic pain in cancer patients. Due consideration of the emotional and motivational status of the patient will make it possible to choose between the different effect profiles of these drugs. However, the use of psychotropic drugs should complement, and cannot replace, empathic care from the physician.