Table 2.

Proposed diagnostic criteria by Fahn and Williams27 for the diagnosis of functional dystonia

Documenteda Persistent relief by psychotherapy, psychological suggestion, including physiotherapy, or by administration of placebos or the patient was witnessed free of symptoms when believing being unobserved

Clinically establisheda Dystonia is inconsistent over time or is incongruent with classical dystonia and at least one of the following:  1. Presence of other psychogenic signs  2. Multiple somatizations  3. Obvious psychiatric disturbance is present

Probable Symptoms are inconsistent or incongruent with classical dystonia or psychogenic signs or somatizations are present.

Possible Dystonic movements are consistent and congruent for organic dystonia, but there is an obvious emotional disturbance.

^aThe revised version of their criteria merged the definition of both categories as “clinically definite.”30