Pain perception in major depressive disorder: A neurophysiological case-control study

BACKGROUND: Depression and pain may sometimes be related conditions. Occasionally, depression may be associated with physical symptoms, such as back pain and headache. Moreover, depression may impair the subjective response to pain and is likely to influence the pain feeling. Conversely, chronic pain may represent an emotional condition as well as physical sensation, and can influence both the mood and behaviour. AIM: To better understand the relationship between pain and depression, we therefore assessed the pain threshold and the tolerance pain threshold in patients with depressive disorders. MATERIALS AND METHODS: We conducted a case-control study and selected patients who had recently received a diagnosis of major depression (DSM-IV), before treatment, and without any significant pain complaints. Age- and sex-matched healthy controls were also included. Tactile and pain thresholds were assessed in all subjects through an electrical stimulation test. All results were compared between the groups. RESULTS: 27 patients and 27 age-matched healthy controls were included in the study. Tactile, pain and tolerance thresholds were evaluated in all subjects. The pain threshold and pain tolerance were lower in patients with major depression than controls. All differences were statistically significant (p<0.05). CONCLUSION: These results suggest the abnormal processing of pain stimuli in depressive disorders.