What Is Conversion Disorder?

Learn the Symptoms, Risk Factors, and More

blurry vision
A symptom of conversion disorder is blindness or double vision. Markus Spiering/EyeEm/Getty Images

Understanding the medical definition of conversion disorder (also known as functional neurological symptom disorder), along with its symptoms and risk factors, is the first step toward getting help for yourself or someone you love.

What Is Conversion Disorder?

Conversion disorder is a psychological condition that causes symptoms that appear to be neurological, such as paralysis, speech impairment, or tremors.

It is a relatively rare mental illness with fewer than 25 cases reported in a population of 100,000, according to the National Organization for Rare Diseases. It is categorized as a type of somatoform disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the leading diagnostic guide for the mental health profession.

There's typically a sudden onset of symptoms that affect voluntary motor or sensory function — and these symptoms can disappear just as suddenly, without any physiological reason. The symptoms can be about any neurological deficit imaginable, including paralysis, loss of voice (aphonia), disturbances in coordination, temporary blindness, loss of the sense of smell (anosmia) or touch (anesthesia).

Diagnosing Conversion Disorder

The DSM-5 offers several specific criteria for diagnosing conversion disorder, including: 

  • There must be at least one symptom of sensory or motor impairment.
  • Symptoms are not caused by neurological condition, physical disease or substance abuse.
  • Symptoms are preceded by conflict or psychological stress.
  • Symptoms are not better explained by somatization disorder or another psychological condition.

Risk Factors for Conversion Disorder

Conversion disorder is usually caused by a psychological reaction to a highly stressful event or emotional trauma.

For example, a soldier who subconsciously wishes to avoid firing a gun may develop paralysis in his or her hand. The disorder does not necessarily develop right away, though, so it's important to disclose recent and past stress when speaking to your therapist. Other risk factors of conversion disorder include:

  • Being female; women have a higher risk of developing the disorder
  • Having a mental health condition, including mood or anxiety disorders, dissociative identity disorder (multiple personality disorder) or other personality disorders
  • Having a neurological disease, such as epilepsy
  • Having a family member with conversion disorder
  • Being highly conscientious, hard-working, compulsive and a perfectionist
  • A history of physical or sexual abuse and neglect as a child

Symptoms of Conversion Disorder

The physical symptoms of conversion disorder are often described as your body's way of dealing with the unresolved stress or unexpressed emotions that triggered the disorder. In other words, the physical symptoms distract the person from the emotional duress.

Conversion disorder typically affects movement function as well as the senses. Some common red flags include:

  • Weakness or paralysis
  • Abnormal walking or tremors
  • Loss of balance
  • Trouble swallowing or feelings of "a lump" in your throat
  • Seizures or convulsions
  • Episode of unresponsiveness
  • Numbness or loss of the sensation of touch 
  • Slurred speech or inability to speak
  • Blindness or double vision
  • Deafness or problems hearing

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