Pain, anxiety, and contingent negative variation: a clinical and pharmacological study.

Contingent negative variation (CNV) behavior was studied in 16 volunteers who were suffering from spontaneous recurrent pain syndromes (idiopathic trigeminal neuralgia, classic migraine). The subjects were divided into two groups, "more anxious" and "less anxious," based on psychometric tests (MMPI and STAI X2). The CNV recordings were carried out, respectively, in basal resting state, during an episode of pain, while under anxiolytic treatment, and lastly, during an episode of pain while under anxiolytic therapy. CNV voltage decrease and frequent appearance of postimperative negative variation (PINV) were observed when pain was present during the recording session. These phenomena were more marked when the pain was accompanied by a greater degree of anxiety. Finally, our results suggest that this slow evoked potential is sensitive to various degrees of anxiety and to pain perception in man, making it useful in the investigation of pain as a complex sensation.