Differentiation of organic and psychogenic paralysis

1. Big picture

This topic is an exam classic because paralysis may be caused by structural neurological disease, but it may also be functional/psychogenic. The examiner wants you to show that you can recognize real neurological localization, but also avoid two dangerous mistakes:

1. Calling an organic emergency “psychogenic” too early, for example stroke, spinal cord compression, Guillain-Barré syndrome, myasthenic crisis, or cauda equina syndrome.
2. Calling functional paralysis “fake” or malingering, which is wrong. Functional weakness is usually involuntary and belongs to functional neurological disorder.

Modern terminology prefers functional paresis/paralysis rather than “psychogenic paralysis,” but the older exam title uses psychogenic. In the exam, you can say:

Psychogenic paralysis is now usually called functional neurological weakness. It is diagnosed by positive clinical signs of inconsistency and incongruence with neuroanatomy, not merely by normal imaging.

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