Recently, local morphologic alterations of the brain in areas ascribable to the transmission of pain were detected in patients suffering from phantom pain, chronic back pain, irritable bowl syndrome, fibromyalgia and two types of frequent headaches. These alterations were different for each pain syndrome, but overlapped in the cingulate cortex, the orbitofrontal cortex, the insula and dorsal pons. These regions function as multi-integrative structures during the experience and the anticipation of pain. As it seems that chronic pain patients have a common "brain signature" in areas known to be involved in pain regulation, the question arises whether these changes are the cause or the consequence of chronic pain. The author suggests that the gray matter change observed in chronic pain patients are the consequence of frequent nociceptive input and should thus be reversible when pain is adequately treated.