Conversion Disorder (Functional Neurological Symptom Disorder) 321
Functional Consequences of Conversion Disorder
Individuals with conversion symptoms may have substantial disability. The severity of dis-
ability can be similar to that experienced by individuals with comparable medical diseases. 
Differential Diagnosis
If another mental disorder be tter explains the symptoms, th at diagnosis should be made.
However the diagnosis of conversion disorder may be made in the presence of another
mental disorder. 
Neurological disease. The main differential diagnosis is neurological disease that might
better explain the symptoms. After a thorough  neurological assessment, an unexpected
neurological disease cause for the symptoms is rarely found at follow up. However, reas-
sessment may be required if the symptoms appe ar to be progressive. Conversion disorder
may coexist with neurological disease.
Somatic symptom disorder. Conversion disorder may be diagnosed in addition to so-
matic symptom disorder. Most of the somati c symptoms encountered in somatic symptom
disorder cannot be demonstrated to be clea rly incompatible with pathophysiology (e.g.,
pain, fatigue), whereas in conversion disorder , such incompatibility is required for the di-
agnosis. The excessive thoughts, feelings, and behaviors characterizing somatic symptom
disorder are often absent  in conversion disorder.
Factitious disorder and malingering. The diagnosis of conversion  disorder does not re-
quire the judgment that the symptoms are not intentionally produced  (i.e., not feigned),
because assessment of conscious intention is  unreliable. However definite evidence of
feigning (e.g., clear evidence that loss of fu nction is present during the examination but not
at home) would suggest a diagno sis of factitious disorder if the individual’s apparent aim
is to assume the sick role or malingering if the aim is to obtain an incentive such as money.