according to research published in the January issue of Headache. The research may be the first to show that personality traits predict response to onabotulinumtoxin A in this population.
“These findings point out that conducting an evaluation of personality traits in patients with chronic migraine might be helpful in the prediction of the course and election of the treatment, as well as identifying patients who might benefit from a multidisciplinary approach,” wrote Alicia Gonzalez-Martinez, MD, of the Hospital Universitario de La Princesa and Instituto de Investigación Sanitaria de La Princesa in Madrid and colleagues. “Categorical questionnaires such as the Salamanca screening test seem to be useful for this purpose.”
Researchers used ICD-10 personality criteria
Personality patterns in patients with migraine and other primary headaches have been the subject of decades of research. Munoz et al. found that certain personality traits are associated with migraine and chronic migraine, and this association may influence clinical management and treatment. The effect of personality traits on response to treatment, however, had not been studied previously.
Dr. Gonzalez-Martinez and colleagues hypothesized that cluster C traits (e.g., obsessive-compulsive, dependent, and anxious), as defined by ICD-10, are associated with nonresponse to onabotulinumtoxin A. To test this hypothesis, they conducted a case-control observational study in a cohort of patients with chronic migraine. Eligible patients presented to one of two headache units of a tertiary hospital between January and May 2018. The investigators obtained a complete headache history and demographic information from each patient. Patients had at least two treatment cycles of onabotulinumtoxin A. Dr. Gonzalez-Martinez and colleagues defined treatment response as a reduction in the number of monthly migraine days of at least 50% after at least two treatment cycles.
The investigators assessed participants’ personality traits by administering the Salamanca test, a brief categorical inventory that examines 11 personality traits using 22 questions. Patients completed the test at the beginning of the study period and before they were classified as responders or nonresponders.
Medication overuse was a potential confounder
The study population included 112 patients with chronic migraine. One hundred patients (89%) were women. Participants’ mean age at initiation of onabotulinumtoxin A treatment was 43 years. The population’s mean duration of chronic migraine was 29 months. Eighty-three patients (74.1%) had medication overuse, and 96 (85.7%) responded to onabotulinumtoxin A.
Cluster A traits in the population included paranoid (prevalence, 10.7%), schizoid (38.4%), and schizotypal (7.1%). Cluster B traits included histrionic (50%), antisocial (1.8%), narcissistic (9.8%), emotional instability subtype impulsive (27.7%), and emotional instability subtype limit (EISL, 24.1%). Cluster C traits were anxious (58.9%) anancastic (i.e., obsessive-compulsive, 54.5%), and dependent (32.1%).
The investigators found no differences in demographics between responders and nonresponders. In a univariate analysis, dependent traits (e.g., passivity and emotional overdependence on others) and EISL traits (e.g., impulsivity and disturbed self-image) were significantly more common among nonresponders. In a multivariate analysis, dependent traits remained significantly associated with nonresponse to onabotulinumtoxin A.
Medication overuse was a potential confounder in the study, according to Dr. Gonzalez-Martinez and colleagues. One of the study’s limitations was its absence of a healthy control group. Another was the fact that the psychometrics of the Salamanca screening test have not been published in a peer-reviewed journal and may need further examination.
Dependent personality “may also be part of the proposed chronic pain sufferer personality,” wrote the investigators. “Early detection of personality traits could improve management and outcome of chronic migraine patients. Additionally, the possibility to predict the effectiveness of onabotulinumtoxin A therapy may reduce costs and latency time of effect in patients with improbable effectiveness.”
The study had no outside funding, and the authors reported no conflicts of interest.
SOURCE: Gonzalez-Martinez A et al. Headache. 2020;60(1):153-61.