Understanding Conversion Disorders: Back to Freud’s Theory

Aybek S, Nicholson TR, Zelaya F, et al. Neural correlates of recall of life events in conversion disorderJAMA Psychiatry 2014;71:52-60.

Functional or conversion disorders (CD) are among the com-monest conditions that neurologists encounter1 and are fre-quently observed in movement disorder clinics. Despite this,little is known about their pathophysiology, diagnostic meth-ods, treatment, or prognosis.2 In his classic works, SigmundFreud postulated that repression of psychological conflictswas converted into physical symptoms. Imaging techniqueshave attempted to study these theories, and a variety ofstudies have suggested dysfunction in the sensory-motornetwork in such patients with CD.3

In a recent study, Aybek et al.4 hypothesized that sup-pressed memories could be detected by functional (f)MRIduring recall of stressful life events considered causal in CD.The sample consisted of 12 patients with sensory-motorsymptoms diagnosed with CD and 13 age- and sex-matched neurologically healthy controls. A semistructuredinterview (Life Events and Difficulty Schedule) covering awide spectrum of life events was applied. Events weredefined as “escape” (a subsequent illness would minimizethe consequence or effect of the event, e.g., announcementfrom spouse that he or she is leaving home), severe (a sub-sequent illness could not minimize the consequences of theevent, e.g., spouse being admitted to the hospital with asevere health problem), or neutral (normal events of dailylife, e.g., a visit from a cousin). During the fMRI, statementscovering subjects’ personal events were shown to subjects,and images obtained during recall of escape and severeevents were compared with neutral events in both patientsand controls. The researchers emphasize four main findings:(1) increased left dorsolateral prefrontal cortex (DLPFC)activity and reduced hippocampal and parahippocampalactivity in the escape condition in patients, compared tocontrols, suggesting direct memory suppression mediatedby top-down regulation of the DLPFC, as opposed tothought substitution; (2) increased activity in the right sup-plementary motor area (SMA) and temporoparietal junctionin patients, possibly related to symptom development; (3)decreased right inferior frontal cortex activity in patients,indicating impaired emotional inhibition; and (4) increased

connectivity between the right SMA and left amygdala inpatients, suggesting that there is an abnormal limbic-motorinteraction resulting in abnormal response to emotionalstress. These findings support the idea that the way emo-tionally stressful events are cognitively processed can beassociated with development of physical symptoms.Although the study contributes to our understanding of thepathophysiology of CD manifesting with negative symptoms(and may provide a biological correlation with Freud’stheory), further studies including patients with positivesymptoms, such as functional movement disorders, are nec-essary before generalizing the results. Finally, it is importantto keep in mind that psychological conflicts are common,but do not always present in CD, and, as such, many fac-tors are involved in the pathophysiology.5

Camila C. Aquino, MD, MSc

Susan H. Fox, MRCP (UK), PhD

Movement Disorder Center, Edmond J. Safra Program in Parkinson

Research, Toronto Western Hospital, Toronto, Ontario, Canada

References1. Carson AJ, Brown R, David AS, et al. Functional (conversion)

neurological symptoms: research since the millennium. J NeurolNeurosurg Psychiatry 2012;83:842-850.

2. Feinstein A. Conversion disorder: advances in our understanding.CMAJ 2011;183:915-920.

3. Voon V, Brezing C, Gallea C, Hallett M. Aberrant supplemen-tary motor complex and limbic activity during motor prepara-tion in motor conversion disorder. Mov Disord 2011;26:2396-2403.

4. Aybek S, Nicholson TR, Zelaya F, et al. Neural correlates ofrecall of life events in conversion disorder. JAMA Psychiatry2014;71:52-60.

5. Lang AE, Voon V. Psychogenic movement disorders: past devel-opments, current status, and future directions. Mov Disord2011;26:1175-1186.

------------------------------------------------------------Published online in Wiley Online Library(wileyonlinelibrary.com). DOI: 10.1002/mds.25907

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720 Movement Disorders, Vol. 29, No. 6, 2014