Illness Anxiety Disorder 317
hood abuse or of a serious childhood illness may predispose to deve lopment of the disor-
der in adulthood. 
Course modifiers. Approximately one-third to one-half of individuals with illness anx-
iety disorder have a transient form, which is associated with less psychiatric comorbidity,
more medical comorbidity, and less severe illness anxiety disorder. 
Culture-Related Diagnostic Issues 
The diagnosis should be made with caution in  individuals whose ideas about disease are
congruent with widely held, culturally sanctioned beliefs. Little is known about the phe-
nomenology of the disorder acro ss cultures, although the prevalence appears to be similar
across different countries with diverse cultures.
Functional Consequences of  Illness Anxiety Disorder
Illness anxiety disorder causes substantial role impairment and decrements in physical
function and health-related quality of life. He alth concerns often interfere with interper-
sonal relationships, disrupt family life,  and damage occupational performance. 
Differential Diagnosis
Other medical conditions. The first differential diagnostic  consideration is an underly-
ing medical condition, includin g neurological or endocrine conditions, occult malignan-
cies, and other diseases that affect multiple  body systems. The presence of a medical
condition does not rule out the possibility of coexisting illness anxiety disorder. If a med-
ical condition is present, the health-related  anxiety and disease concerns are clearly dis-
proportionate to its seriousnes s. Transient preoccupations related to a medical condition
do not constitute illn ess anxiety disorder. 
Adjustment disorders. Health-related anxiety is a norm al response to serious illness
and is not a mental disorder. Such nonpathologic al health anxiety is clearly related to the
medical condition and is typica lly time-limited. If the health anxiety is severe enough, an