American headache through the decades: 1950 to 2008.

As the American Headache Society approaches its 50th anniversary, it seems worthwhile to step back and survey the many changes in the headache field since the 1950s. Many, perhaps most, of the trends, ideas, and changes we review in this article cannot easily be assigned to a particular decade but we have nonetheless chosen a by-the-decade format because it is a familiar and useful way of understanding history. Our focus is on events in the United States and the American Headache Society; space and the need to limit the scope of the article preclude a full description of the many parallel and influential trends, personalities, and ideas in other parts of the world or in other professional organizations. The authors hope you will find this summary of American Headache Medicine in the last half of the 20th and the beginning of the 21st centuries entertaining and educational.

A review of mechanisms of response to pain therapy: why voodoo works.

A person's response to pain treatment may be due to factors other than the direct effect of analgesics. Amelioration of pain is often associated with modalities that appear to make no scientific sense. This review outlines the mechanisms of pain amelioration other than that by medication. These mechanisms help to explain why pain relief may follow the administration of allopathic modalities. Pain is modulated, enhanced, or diminished by both cerebral and peripheral mechanisms. Cerebral factors include the placebo response, psychological phenomena, and conscious cognitive activation. In addition to evoking endogenous opioids, these central mechanisms activate antinociceptive pathways beginning in the limbic forebrain and relayed in the periaqueductal gray matter to primary afferent nociceptive sites in the spinal cord dorsal horn (and medullary nucleus caudalis). Obvious peripheral factors that may diminish pain perception are those that decrease afferent stimuli. Paradoxically, stimulation of afferent neurons may also ameliorate pain by activating spinal or supraspinal inhibitory mechanisms. Finally, improvement in pain or other symptoms is often falsely attributed to a therapy when remission occurs because the underlying illness has run its normal course.