318 Somatic Symptom and Related Disorders
order, concerns are limited to the individual’s physical appearance, which is viewed as
defective or flawed.
Major depressive disorder. Some individuals with a major depressive episode rumi-
nate about their health and worry excessively about illness. A separate diagnosis of illness
anxiety disorder is not made if these concer ns occur only during major depressive epi-
sodes. However, if excessive illness worry persists after remi ssion of an episode of major
depressive disorder, the diagnosis of illness anxiety disorder should be considered. 
Psychotic disorders. Individuals with illness anxiety disorder are not delusional and
can acknowledge the possibility that the feared disease is no t present. Their ideas do not
attain the rigidity and intens ity seen in the somatic delusions occurring in psychotic dis-
orders (e.g., schizophrenia; delusional disord er, somatic type; major depressive disorder,
with psychotic features). True  somatic delusions are generall y more bizarre (e.g., that an
organ is rotting or dead) than  the concerns seen in illness  anxiety disorder. The concerns
seen in illness anxiety disorder, though not founded in reality, are plausible. 
Comorbidity
Because illness anxiety disorder is a new di sorder, exact co morbidities are unknown. Hy-
pochondriasis co-occurs with anxiety disorders (in particular, generalized anxiety disor-
der, panic disorder, and OCD)  and depressive disorders. Approximately two-thirds of
individuals with illness anxiety disorder are lik ely to have at least one other comorbid ma-
jor mental disorder. Individuals with illness anxiety disorder may have an elevated risk
for somatic symptom disorder  and personality disorders.
Conversion Disorder
(Functional Neurological Symptom Disorder)
Diagnostic Criteria