Functional neurological disorder is common in patients attending chronic pain clinics

Abstract

Background and purpose Chronic pain is a common comorbidity in those with functional neurological disorder (FND); however, the prevalence and characteristics of FND in those with chronic pain is unknown. Methods A retrospective electronic records review was made of consecutive new patients attending a chronic pain clinic of a regional service. Clinical features, medication for and outcome of chronic pain, any lifetime diagnoses of functional disorders, FND, and psychiatric disorders, and undiagnosed neurological symptoms were recorded. Results Of 190 patients attending the chronic pain clinic, 32 (17%) had a lifetime diagnosis of FND and an additional 11 (6%) had undiagnosed neurological symptoms. Pain patients with comorbid FND were more likely to have chronic primary pain (88% with FND, 44% without FND, p < 0.0001), widespread chronic primary pain (53%, 15%, p < 0.00001), and depression (84%, 52%, p < 0.005) and less likely to have a pain‐precipitating event (19% vs. 56%, p < 0.001). However, there was no significant difference between these patients in opiate prescription, benzodiazepine prescription, or pain outcome. Conclusions This first study of FND in a chronic pain patient population found a remarkably high prevalence of FND (17%) and is possibly an underestimation. The size of the overlap indicates that FND and chronic pain research fields are likely to have a lot to learn from each other.

Functional neurological signs in hypermobile Ehlers–Danlos syndrome and hypermobile spectrum disorders with suspected neuropathic pain

“…FND is frequent in chronic pain with a prevalence of 17%, according to a recent report (Mason et al., 2023 ). Despite not having formally established an FND diagnosis in our study, the co‐occurrence of FNS seems even more frequent in hEDS/HSD .…”

Pain and functional neurological disorder: a systematic review and meta-analysis

“…[46][47][48][49][50] A recent study from our own group, which was published after our search was conducted, described FND diagnoses in 17% of 190 patients attending a regional chronic pain service and undiagnosed neurological symptoms in a further 6%. 64 In addition, patients with comorbid FND were more likely to have a chronic primary pain disorder, such as fibromyalgia. These data suggest there is a significant overlap between the FND and chronic pain populations and indicate a potential role for the integration of pain management techniques and services in the treatment of certain patients with FND.…”

Correspondence: Inaccurate reference leads to tripling of reported FND prevalence

“…Earlier this year, a paper in the European Journal of Neurology ( Mason et al, 2023 ) cited a different SNSS paper ( Stone et al, 2009 ) to support the assertion that FND prevalence at outpatient neurology clinics was 5.4 %—far lower than the percentage needed to be the “2nd most common” diagnosis. Moreover, the authors of another paper ( Foley et al, 2022 ) have recently issued a correction for the same misstatement of FND prevalence from the SNSS findings as the one identified in Perez et al…”