Functional neurological disorder (FND) is a disorder of the way your nervous system functions (works). The disorder exists without there being a problem in the structure of your nervous system or brain. Some people describe it as a software problem rather than a hardware problem.
FND is not well understood by many people, even some doctors. It's a rare condition, but it's being recognised more often than it used to be.
If you have FND, you don't have control over any of your symptoms. Your symptoms are likely to come and go and may change over time. This can make it difficult for others to understand FND. It can also lead to frustration and a feeling that others don't believe you.