Orbitofrontal dysfunction and medication overuse in patients with migraine.

Objective: Orbitofrontal cortex (OFC) dysfunction and poor decision making have been described in patients with chronic migraine and medication overuse. These neurobiological underpinnings might explain dependency-like behaviors often described in this condition, such as loss of control over painkillers, high rates of relapse after detoxification, and compromised social functioning. We investigate whether the OFC impairment was a persistent trait in migraine, independent of clinical and affective features, a dynamic result of the need to cope with the increased pain and disability, or a temporary consequence of medication overuse.

Methods: For this purpose, we compared 40 chronic migraineurs with medication overuse, 40 episodic migraineurs, and 40 matched healthy controls. The examination consisted of a clinical interview, Anxiety and Depression Hamilton Scales, Severity of Dependence Scale, and Migraine Disability Assessment questionnaire. A neuropsychological assessment of orbitofrontal function was made through the Iowa Gambling Task (IGT). Chronic migraineurs with medication overuse were followed for a year after detoxification.

Results: We found an impaired decision-making performance among chronic and episodic migraineurs that seems independent of the patients' clinical and affective status. Contrary to the psychiatric and clinical improvement shown 1 year after the detox, CM patients exhibited a persistent IGT deficit. No significant differences in OFC functioning were found between the CM patients who relapsed into medication overuse after detox and those who did not.

Conclusions: The present findings suggest the presence of a persistent OFC dysfunction in migraine as a psychobiologic trait that is not influenced by the presence of medication overuse, the clinical severity of the disease, or the patient's affective status. Further studies are needed to elucidate the etiopathological role of OFC in migraine and medication overuse.