[1][2] The intended contrast is with an organic brain syndrome, where a pathology (disease process) which affects the body's physiology can be identified.
[citation needed] The diagnosis is made based on positive signs and symptoms in the history and examination during consultation of a neurologist.
While these symptoms are very real, their origin is complex, since it can be associated with severe psychological trauma (conversion disorder), and idiopathic neurological dysfunction.
[11] The new findings advance current understanding of the mechanisms involved in this disease, and offer the possibility of identifying markers of the condition and patients' prognosis.
Patients with functional neurological disorders are more likely to have a history of another illness such as irritable bowel syndrome, chronic pelvic pain or fibromyalgia but this cannot be used to make a diagnosis.
FND can occur alongside other neurological diseases and tests may show non-specific abnormalities which cause confusion for doctors and patients.
[28] Non-epileptic seizures account for about 1 in 7 referrals to neurologists after an initial episode, while functional weakness has a similar prevalence to multiple sclerosis.
[29][clarification needed] Treatment requires a firm and transparent diagnosis based on positive features which both health professionals and patients can feel confident about.
Nielsen et al. have reviewed the medical literature on physiotherapy for functional motor disorders up to 2012 and concluded that the available studies, although limited, mainly report positive results.
Availability of expertise is limited and they may feel that they are being dismissed or told 'it's all in your head' especially if psychological input is part of the treatment plan.
Jean-Martin Charcot argued that, what would be later called FND, was caused by "a hereditary degeneration of the nervous system, namely a neurological disorder".
It referred instead to symptoms that could not be explained by a recognised organic pathology, and was therefore believed to be the result of stress, anxiety, trauma or depression.
[37] Today, there is a growing understanding that symptoms are real and distressing, and are caused by an incorrect functioning of the brain rather than being imagined or feigned.