Gender, Abuse, and Functional Movement Disorders: From His‐story to the Future

The history of functional neurological disorder (FND; conversion disorder) has been irrevocably bound to gender for millennia. After all, the pathophysiological implication of the term “hysteria” is that the disorder can only exist in those with a uterus. But hysteria is not a term that is owned by medicine alone. Its use in general language is important given that it indicates that someone is making a big deal out of a trivial problem and also that the person doing so is likely to be a woman. Hysteria in common language is typically said by men about women, and if it is used to refer to a man, it comes with the implication that he is not a “real” man. Given this history, it is hard to separate FND from gender, politics and ethics, and yet we must consider the scientific dimension to this topic.

In this issue of Movement Disorders Clinical Practice (MDCP), two articles approach this by stratifying two large cohorts of patients with functional movement disorders (FMDs) by gender. In the article by Baizaball‐Carvallo and Jankovic,1 a retrospective chart and video review of 196 patients with FMD revealed 70% of the cohort to be female. This female predominance was enhanced in the young, but in those presenting over the age of 50, males and female proportions were equal. There were some gender‐driven differences in phenotype, with functional dystonia more common in females and a trend for gait disturbance to be commoner in males.

Kletenik and colleagues2 specifically considered the issue of sexual abuse. They used a standardized instrument to assess the presence of trauma (The Trauma Life Events questionnaire3) in a cohort of 199 patients diagnosed with FMD compared to 95 neurological control patients without FMD. Lifetime prevalence of sexual abuse in the cohorts was 48% of women and 9% of men in the FMD cohort and 16% of women and 7% in the neurological control cohort. Furthermore, the relative risk of developing FMD conferred by being sexually abused was higher in women compared to men.

As well conducted as they are, neither study can fully answer the epidemiological question of whether more females suffer from FND than males (attributable to referral and diagnosis bias) or whether abuse has a mechanistic role (because of the bias of using a self‐report questionnaire). The only design that could fully answer this question, though unfeasible, is cohort studies of males and females with and without abuse prospectively assessing the emergence of FND. However, the findings of these two articles are in keeping with many previous studies. Rates of FMD (and FND in general) do appear to be higher in women than men, and sexual abuse, along with other adverse experiences in childhood or adulthood, is commoner in people with FND than healthy or neurological controls. So, what are the implications for research and clinical practice?

First, there remains a question whether some of the gender imbalance observed is related to a reluctance of clinicians to diagnose FMD in men and conversely an overeagerness to make the diagnosis in women. Historically, given the anatomical impossibility of a man having hysteria, functional ailments in men were often categorized as hypochondriasis.4 However, during the 19th century, descriptions of “masculine hysteria” challenged this view. Briquet reported a male/female ratio of 1:20, and Charcot published over 60 cases.4 The study from Baizaball‐Carvallo and Jankovic confirms a current ratio of 1:2.5. The evolution of these ratios illustrates the influence of society and hypotheses on scientific data and the fact that researchers may find only what they look for. In other words, if we hypothesize that being female is a strong risk factor, science may tend to prove it given that our research designs are prone to bias. The implication for our clinical practice is to ensure best practice in our diagnosis, using positive historical features and clinical signs and specific investigations, and not to use gender as a criterion to sway our clinical judgement. We need to be as vigilant with this as we should with other associated, but nondiagnostic, clinical features. Presence of anxiety, depression, recent stressors, or past trauma should not be the foundation of a diagnosis of FMD. If they are, then the possibility of diagnostic error is high, as it will be for those many patients with FMD who do not have these clinical features.

Second, there is a pathophysiological question that is raised, but unanswered, by these studies. If we accept that there is an influence of gender on risk of development of FMD (as there is for other disorders, e.g., multiple sclerosis), what is driving this phenomenon? Proper scientific study of this question must consider biological as well as psychological factors. For example, testosterone affects approach‐avoidance responses to threat.5 As Klerenik and colleagues2 point out, there is evidence that sexual abuse can affect sense of embodiment and self‐agency. There has been increasing interest in the relevance of abnormalities in interoception in FND,6, 7 arguably the network that it is at the heart of embodiment and self‐agency,8 and it is possible that this could be a route by which sexual abuse predisposes people to development of FMD. Interestingly, there are gender differences in interoceptive processing9 that could provide a partial explanation for the general sex bias in people with FMD beyond the impact of sexual abuse. However, there is much to do to really understand the pathophysiological drivers of the effects of gender and sexual abuse, and we should not shy away from exploring them, despite the difficult historical background of this diagnosis with regard to gender‐based prejudice and discrimination.

Third, there is the question of whether and how the data on sexual abuse should alter our clinical practice. There has been a hard‐won battle to try to move away from a simple causal association between the development of FMD and psychological factors (abuse, depression, and personality disorder). This simple association is embodied within specific diagnostic terms such as “conversion disorder” and “psychogenic.” The growing use and acceptance (even within diagnostic classification systems) of the term “functional” is testament to the success of this shift. However, the purpose was never to deny the presence and potential etiological and therapeutic implications of these factors, simply that one should not make a diagnosis based on their presence or absence.

So, what is the clinical meaning of the presence of a history of sexual abuse in a patient with FMD diagnosed according to best practice? The answer is unknown, but seems likely to be complex. We have met many patients who have been significantly harmed by pop‐psychology approaches to their past trauma—“everything will be better if you just work through your trauma”;” you've not got better because you just can't let go of your trauma.” These victim‐blaming approaches are scientifically illiterate and directly harmful. The same is true of blundering into past trauma in the initial neurological consultation by giving the impression that if it is there, then it is the only reason why the person is now ill, and if it is not there, then the only explanation is that the person must have forgotten about it. These simplistic interpretations of Freudian conversion and repression theories continue to pervade our interactions with people with FMD and are not helpful. We should be mindful of the fact that traumatic experiences are risk factors for the development of psychiatric disorders in general, including schizophrenia, yet it seems particular to FMD that we assume that we can fix the problem, as if by magic, just by telling someone to acknowledge the presence of these experiences.

There are likely to be fundamental changes in brain function that occur in some people following sexual abuse, with ramifications for somatic and emotional experiences, personality, psychological well‐being, and social interactions. While many of these factors may be relevant to the development and persistence of FMD in some people, only a subset of them may be changeable through treatment. Treatments that have nothing specifically to do with trauma are effective in people with FMD and past trauma, just as they are in people without trauma. While for some people (perhaps particularly those with posttraumatic stress disorder) trauma therapy may be relevant, we should not consider treatment of trauma to be essential or primary in our management of all people with FMD. As with many things, a careful and compassionate application of scientific method to an individualized program of care is likely to bring us and our patients to the goal we seek: to understand, not to judge, and to move forward to a better future, rather adding to the injustices of the past.

Author Roles

(1) Research Project: A. Conception, B. Organization, C. Execution; (2) Statistical Analysis: A. Design, B. Execution, C. Review and Critique; (3) Manuscript Preparation: A. Writing of the First Draft, B. Review and Critique.

M.J.E.: 3A, 3B

S.A.: 3B

Disclosures

Ethical Compliance Statement

IRB approval and patient consent were not necessary for this work. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines.

Funding Sources and Conflicts of Interest

The authors report no sources of funding and no conflicts of interest.

Financial Disclosures for previous 12 months

M.J.E. has received funding for educational activities from Merz Pharma.