Stiff-Person Syndrome: Symptoms & Signs

Medically Reviewed on 5/22/2020

Stiff-person syndrome is the name given to a rare condition that affects the nervous system, principally the brain and spinal cord. Affected people often have blood tests showing glutamic acid decarboxylase (GAD) antibodies. The condition has also been called stiff-man syndrome.

Signs and symptoms of stiff-person syndrome include

The muscle spasms may cause uncontrolled falls, dislocated limbs, and broken bones. Other associated symptoms can include an increased sensitivity to noise and emotional distress. The condition tends to worsen over time.

Cause of stiff-person syndrome

Doctors do not understand its cause, but they think it is related to an autoimmune reaction.

Other stiff-person syndrome symptoms and signs

  • Extreme Muscle Stiffness
  • Hunched Posture
  • Impaired Mobility
  • Painful Muscle Spasms
  • Rigidity
  • Stiff Arms and Legs
  • Sudden Movements


The abbreviated term ADHD denotes the condition commonly known as: See Answer

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Jameson, J. Larry, et al. Harrison's Principles of Internal Medicine, 20th Ed. New York: McGraw-Hill Education, 2018.