Functional neurologic disorders — a newer and broader term that includes what some people call conversion disorder — feature nervous system (neurological) symptoms that can't be explained by a neurological disease or other medical condition. However, the symptoms are real and cause significant distress or problems functioning.
Signs and symptoms vary, depending on the type of functional neurologic disorder, and may include specific patterns. Typically these disorders affect your movement or your senses, such as the ability to walk, swallow, see or hear. Symptoms can vary in severity and may come and go or be persistent. However, you can't intentionally produce or control your symptoms.
The cause of functional neurologic disorders is unknown. The condition may be triggered by a neurological disorder or by a reaction to stress or psychological or physical trauma, but that's not always the case. Functional neurologic disorders are related to how the brain functions, rather than damage to the brain's structure (such as from a stroke, multiple sclerosis, infection or injury).
Early diagnosis and treatment, especially education about the condition, can help with recovery.