A biological measure of stress levels in patients with functional movement disorders

Abstract

Introduction While the presence of co-existing psychological stressors has historically been used as a supportive factor in the diagnosis of functional neurological disorders, many patients with functional neurological disorders deny the presence of these stressors. The stress response circuitry in these patients remains largely unexplored. Methods We performed an observational study examining biological stress levels in patients with functional movement disorders as compared with matched healthy controls. Specifically, we compared levels of circulating cortisol, the end-product of the hypothalamic-pituitary-adrenal axis. Salivary cortisol samples were collected from patients with “clinically definite” functional movement disorders (n=33) and their age- and sex-matched controls (n=33). Collections were performed at five standardized time points, reflecting participants’ diurnal cortisol cycles. To rule out confounders, participants also underwent extensive psychological assessment including Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Hamilton Anxiety Rating Scale, and Hamilton Rating Scale for Depression. Results Patients with functional movement disorders did not differ from matched controls with respect to levels of circulating cortisol. Conclusion We demonstrate that current stress levels are not altered in patients with functional movement disorders. Our results warrant careful review of current management of patients with functional neurological symptoms, and suggest that the insistence on heightened stress levels in these patients is unjustified.

Impaired resting vagal tone in patients with functional movement disorders

“…Our study contrasts with previous work from our group demonstrating normal functioning in FMD patients of another critical stress response system, the hypothalamic-pituitary adrenal (HPA) axis[14]. However, while the HPA axis and ANS generally act in a complementary manner to maintain homeostasis during times of stress, various upstream modulators, for example within the limbic forebrain, are known to preferentially influence the ANS[25].…”

“…Thirty-eight age- and sex-matched HCs were recruited from the NIH Clinical Research Volunteer Program database. Participants partially overlap with those reported in a previous manuscript exploring the hypothalamic-pituitary-adrenal axis in FMD[14]. Exclusion criteria for all participants included: a) history of cardiac disease; b) use of heart-rate altering medication; c) comorbid neurological disease; d) comorbid psychotic disorder, bipolar disorder, current substance abuse or current depressive episode; e) history of traumatic brain injury with loss of consciousness; f) active autoimmune disorder; g) current suicidal ideation; h) disease severity requiring inpatient treatment; and i) use of tricyclic antidepressants or antiepileptic medication.…”

Insights into Chronic Functional Movement Disorders: The Value of Qualitative Psychiatric Interviews

“…Patients partially overlap with those reported in previous manuscripts. 7 Exclusion criteria included: a) comorbid neurological disease; b) psychotic disorder, bipolar disorder, current substance abuse; c) history of traumatic brain injury with loss of consciousness; d) active autoimmune disorder; e) current suicidal ideation; f) disease severity requiring inpatient treatment; g) current use of tricyclic antidepressants or antiepileptic medication; and h) pregnancy. All participants provided written informed consent.…”

Stress and functional neurological disorders: mechanistic insights

“…The same group found that participants with seizure-variant FND showed higher ‘approach-avoidance congruency’ for angry faces on a computerised task in comparison to controls, which correlated with basal salivary cortisol. (51 s) Another study of 33 patients with functional movement disorders found no significant differences from healthy controls in salivary cortisol, but over half were taking variable doses of psychotropic mediations, with potentially sedative or anxiolytic effects capable of influencing the HPA response 43. A recent study found that participants with motor FND had higher background salivary cortisol and (sympathetic) α amylase than controls, associated with the number and impact of stressful life events they had experienced.…”