Are Functional Disorders Driven By Underlying Psychological Distress?

By Anton Scamvougeras and David Castle

An intriguing discussion is going on in one corner of the world of clinical neuropsychiatry that has implications that are important for how a very common group of disorders are understood and, therefore, treated. ‘Functional disorders’ are conditions where physical symptoms and signs, after very thorough assessment, cannot be attributed to a general medical condition. Individuals with these conditions make up about 22% of all people presenting for primary medical care, and over 30% in some neurology clinics. The matter of debate is whether we know enough to attribute causation of these conditions to underlying psychological distress, or whether we should take an agnostic approach to causation.

Up until about 20 years ago, most clinicians were in general agreement that there occur ‘medically unexplained’ physical symptoms and signs that represented the unconscious and involuntary expression of emotional distress. Various labels were applied to these conditions, including ‘hysteria’, ‘psychogenic’, ‘somatoform’, and ‘conversion’. They proved notoriously challenging to treat, and clinicians were hindered by imperfect classification systems which also served to keep the conditions out of the spotlight.

In the lead up to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5; 2013), some neurologists and psychiatrists began to call for a fundamental change - for a move away from the idea that these conditions were caused by psychological distress. Arguments behind this included the idea that from an empirical perspective one could never be absolutely certain of causation, and that the thought of psychiatric underpinnings was unpopular with many patients - it was claimed to ‘stigmatize’ these patients.

Subsequently, the DSM-5 section dealing with these conditions cemented the move away from psychological primacy. Since then, agnosticism regarding causation has become a mantra: the idea that psychological factors are integral to these disorders rather than 'co-morbid' is now deemed 'radical', or 'out of date', and psychiatrists are being encouraged to join an agnostic ‘renaissance'. Leaders in the field take care to attribute the conditions to 'brain network dysfunction’ and a vast amount of research effort has been directed at seeking neurobiological underpinnings.

This fundamental change in the way that these conditions are understood has been made without any persuasive supporting evidence. Indeed, there remains - on balance - good evidence that underlying dysphoria is the causative mechanism, including the facts that these populations show very high rates of anxiety, depression, and history of childhood trauma; and that they respond to treatments where a psychological-engine model of causation is assumed.

Despite the current mainstream position, many clinicians continue to use psychological-engine models to understand and help these patients. A recent survey showed that the majority of Italian psychiatrists still see ‘conversion’ as a psychological phenomenon, yet the authors of that study roundly chastised them for this.

Ironically, clinicians and researchers who have prominently supported the agnostic position continue to emphasize the need for psychiatric assessments in all patients, recommend psychotherapies, and, if they use medications they are invariably psychotropics. This can be argued to be disingenuous.

Our current ‘Perspectives’ paper in the Canadian Journal of Psychiatry (‘Functional Neurological Disorders: Challenging the Mainstream Agnostic Causative Position’) argues that the dismissal of the psychological-engine model to explain these conditions has been a mistake, and that this has not served patients, clinicians, nor researchers well.

How does a young psychiatrist or neurologist attempt to treat a ‘brain network dysfunction’? We argue that the agnostic position makes for oblique formulations and a hesitant clinical approach; that the simultaneous emphasis on ‘rule-in’ signs is unnecessary; and that the intended ‘destigmatization’ is actually failing.

We also argue that the agnostic position has misdirected research efforts aimed at understanding the neurobiology of these conditions: most obviously, almost all study designs have used healthy controls rather than psychiatric controls, and have quite likely been describing the brain changes seen in common forms of dysphoria rather than anything specific to functional disorders themselves.

Our paper is a plea for a reappraisal and rebalancing regarding the understanding of these conditions. It is an appeal for a return to seeing psychological factors as central to functional conditions, a position that evidence supports and no evidence refutes. We believe this position will be shown to be valid over time, and will best serve all participants in the field: clinicians, researchers, and, most importantly, those suffering these conditions.

Article Details
Functional Neurological Disorders: Challenging the Mainstream Agnostic Causative Position
Anton Scamvougeras & David Castle
First Published: April 7, 2024
DOI: 10.1177/07067437241245957
The Canadian Journal of Psychiatry

About the Authors

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David Jonathan Castle MBChB MD FRCPsych FRANZCP is Professor, Department of Psychiatry, The University of Tasmania; and Co-Director, Tasmanian Centre for Mental Health Service Innovation. He has wide clinical and research interests, encompassing schizophrenia and related disorders, bipolar disorder, OCD spectrum disorders and disorders of body image. He has a longstanding interest in the impact of licit and illicit substances on the brain and body, and is actively engaged in programmes addressing the physical health of the mentally ill and the mental health of the physically ill. He has published widely in the scientific literature and is a frequent speaker at scientific meetings.

Anton Scamvougeras MBChB FRCPC is a Consultant Neuropsychiatrist in the University of British Columbia Neuropsychiatry Program, and a Clinical Associate Professor in the UBC Department of Psychiatry, Vancouver, BC. He obtained his medical degree in Cape Town, South Africa, and then worked as a family physician in rural Canada before specializing in Psychiatry at McMaster University, Hamilton, Ontario, with fellowship studies in neurosciences, MRI, and research methodology. He has been at UBC since 1994, and has a special interest in understanding and helping individuals with severe Functional/Somatoform Disorders. He also runs the UBC Adult Tourette’s Syndrome Clinic, assisting individuals with Tourette’s and related conditions.