Patients with conversion disorder present with neurological symptoms affecting their voluntary motor system or sensory functions that cannot be fully explained physiologically. Patients may suddenly experience neurological symptoms, such as blindness, deafness, paralysis, inability to speak, seizures, or an inability to walk or stand.
Although these symptoms suggest an illness related to neurological damage, medical tests indicate that the bodily organs and nervous system are fine. In other words, the symptoms, or deficits, suggest a physical condition, but their root is psychological, with unconscious underlying emotional conflicts or stressors present.
Clinical Symptoms of Conversion Disorder
Patients with conversion disorder may experience partial or complete paralysis of arms or legs; seizures; coordination disturbances; a sensation of prickling, tingling, or creeping on the skin; insensitivity to pain; or anesthesia—the loss of sensation.
Vision may be seriously impaired; the person may become partially or completely blind or have tunnel vision, in which the visual field is constricted as it would be if the person were peering through a tube.
AphoniaOpens in new window, loss of the voice other than whispered speech, can also occur. Many people with conversion disorder do not connect their symptoms with their stressful situations.
The earliest writings on psychological disorders describe these symptoms. HysteriaOpens in new window was the term originally used to describe the disorder, which the Greek physician Hippocrates considered to an affliction limited to women and brought on by the wandering of the uterus through the body. (The Greek word hystera means “womb”; the wandering uterus symbolized the longing of the woman’s body to produce a child.)
The term conversion originated with Sigmund Freud, who thought that anxiety and psychological conflict were converted into physical symptoms.
Diagnosis of Conversion Disorder
When a patient reports a neurological symptom, the clinician must be careful to assess whether that symptom has a true neurological basis. It is estimated that genuinely physical problems are misdiagnosed as conversion disorder about 4 percent of the time (Stone, Smyth, et al., 2005).
Sometimes behavioral tests can help make this distinction. Non-epileptic seizure disorderOpens in new window, a common form of conversion disorder, is defined by seizure-like events that occur at the same time that a normal EEG pattern is recorded (Stone et al., 2010).
In another example, arm tremors might disappear when the person is asked to move the arm rhythmically. Leg weakness might not be consistent when tested with resistance (Stone et al., 2010). Tunnel vision, another conversion disorder symptom, is incompatible with the biology of the visual system.
Some symptoms that might seem medically implausible have been shown to have a biological basis. Consider, for instance, the classic example of “glove anesthesiaOpens in new window,” in which the person experiences little or no sensation in the part of the hand and lower arm that would be covered by a glove. For years, this was considered a textbook illustration of anatomical nonsense because the nerves run continuously from the hand up the arm.
Yet now it appears that carpal tunnels syndromeOpens in new window, a recognized medical condition, can produce symptoms like those of glove anesthesia. Nerves in the wrist run through a tunnel formed by the wrist bones and membranes. Swelling in this tunnel can pinch the nerves, leading to tingling, numbness, and pain in the hand.
People who use computer keyboards for many hours a day are at risk for this condition. Beyond glove anesthesia, other symptoms that would intuitively seem difficult to explain medically, such as the perception of a burning sensation when touching a cold object, have clear medical explanations (in this case, ciguateraOpens in new window, a disease caused by eating certain reef fish).
It is estimatd that genuinely physical problems are misdiagnosed as conversion disorder about 4% of the time (Stone, Smyth, et al., 2005). Some tests can help clinicians make an accurate diagnosis. Nonepileptic seizure disorderOpens in new window, a common form of conversion disorder, is defined by seizure-like events that occur at the same time that a normal EEG pattern is recorded (Stone, LaFrance, et al., 2010).
Arm tremors might disappear when the person is asked to move the arm rhythmically. Leg weakness might not be consistent when tested with resistance (Stone et al., 2010). Tunnel visionOpens in new window, another conversion disorder symptom, is incompatible with the biology of the visual system.
To enhance the reliability of diagnoses, the DSM-5 provides guidance to clinicians about how to assess whether symptoms might be medically unexplained.
Some, but not all, people with conversion disorder seem motivated to appear ill. When relevant neurological abilities are tested (e.g., visual tests for a person with a conversion disorder involving blindness), some with conversion disorders perform more poorly than what would be achieved by chance and show evidence of little effort on the tests related to their deficit (Drane, Williamson, et al., 2006).
Some with these disorders endorse multiple implausible and rare neurological symptoms (Benge, Wisdom, et al., 2012). Some report a symptom, such as a tremor, much more continuously than is observed with objective measures, such as wristbands that monitor motion (Parees, Saifee, et al., 2012). Many people with conversion disorder, though, show no signs that they are amplifying their symptoms, when present, any amplification of symptoms may be outside conscious awareness.
Symptoms of conversion disorder usually develop in adolescence or early adulthood. Onset is usally rapid, with symptoms developing in less than one day (Carson & Lehn, 2016). Many patients with conversion disorder experience work-related disability (Carson & Lehn, 2016). An episode may end abruptly, but about 40% show symptoms when reassessed 5 years later (Gelauff, Stone, et al., 2013).
Although there are no community-based studies using diagnostic interviews, the prevalence of conversion disorder is estimated to be less than 1% in the community more common among patients visiting neurology clinics, where as many as 10% of patients have symptoms that have no medical explanation (Carson & Lehn, 2016). More women than men are given the diagnosis. Patients with conversion disorder are highly likely to meet criteria for another somatic symptom disorder (Brown et al., 2007).
Treatment for Conversion Disorder
Three small randomized controlled trials indicate beneficial effects of cognitive behavioral therapy (CBT)Opens in new window for specific forms of conversion disorder. In one trial, researchers randomly assigned 61 individuals who had medically unexplained gait disorders, such as limping or foot dragging, to immediate treatment or a wait-list control (Jordbru, Smedstad, et al., 2014).
As a first step in treatment, therapists explained to patients and their family members that medical tests had not revealed an explanation for gait disturbance but disconnections in the interface of the nervous system and the body are common. Patients were then hospitalized for 3 weeks so that they could take part in daily physical training.
The CBT had two major components.
- First, patients were reinforced for taking part in the training.
- Second, to avoid reinforcing conversion symptoms, the treatment team ignored ongoing signs of gait disturbance.
Patients showed large increases in heir mobility, independence, and quality of life during the CBT intervention, and those gains were present 1 year later. In the other two trials, researchers found that outpatient CBT was more helpful than standard medical care in reducing the rate of nonepileptic seizures (Goldstein, Chalder, et al., 2010).
- Nicholson, T., Stone, J., & Kanaan, R.A.A. (2011). Conversion disorder: A problematic diagnosis. Journal of Neurology, Neurosurgery, and Psychiatry, 82, 1267 – 1273.
- Stone, J., Vuilleumier, P., & Friedman, J.H. (2010). Conversion disorder: Separatign “how” from “why.” Neurology, 74, 190 – 191.