Illness Anxiety Disorder (formerly Hypochondriasis) Differential Diagnoses

Updated: Mar 06, 2018
  • Author: Debra Kahn, MD; Chief Editor: David Bienenfeld, MD  more...
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Diagnostic Considerations

Physical disease must be excluded, which involves evaluation for an extensive number of neurological (eg, myasthenia gravis, multiple sclerosis), endocrinological, and other systemic diseases. Illness anxiety disorder may be diagnosed in someone with a medical illness if the anxiety is out of proportion to the gravity of the illness. The psychiatric differential diagnosis for illness anxiety disorder includes the following disorders: somatic symptom, adjustment, conversion, body dysmorphic, mood, anxiety, and psychotic, and personality. Some of these are discussed in more detail below.

Somatic symptom disorder

This disorder is less restricted than the DSM-IV somatization disorder, and as such, the prevalence is expected to be higher than somatization disorder. The diagnostic criteria are as follows:

A.  Patients present with one or more somatic symptoms that are distressing or result in significant disruption of daily life.

B. Excessive thoughts, feelings, or behaviors related to the somatic symptoms or associated health concerns as manifested by at least one of the following:

  1. Disproportionate and persistent thoughts about the seriousness of one's symptoms
  2. Persistently high levels of anxiety about health or symptoms
  3. Excessive time and energy devoted to these symptoms or health concerns

C.  Although any one of somatic symptoms may not be continuously present, the state of being symptomatic is persistent (typically more than 6 months).

What differentiates somatic symptom disorder from illness anxiety disorder is the patient's focus on symptoms rather than a preoccupation with illness and the accompanying worry. Somatic symptom disorder may be comorbid with medical illness.

Conversion disorder (functional neurolgoical symptom disorder)

Diagnostic criteria is as follows:

A.  One or more symptoms of altered voluntary motor or sensory function.

B.  Clinical findings provide evidence of incompatiblity between the symptoms and recognized neurological or medical conditions.

C.  The symptom or deficit is not better explained by another medical or mental disorder.

D.  The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation.

In contrast with illness anxiety disorder, patients with conversion disorder do not generally present with a concern that they have a serious disease and may (though not necessarily) have a noticeable lack of worry even about their presenting symptom. Common symptom presentations include impaired coordination, paralysis or weakness, tremor, difficulty swallowing, loss of pain or touch sensation, double vision, seizure, or blindness. Conversion disorder is also more common in females, with female-to-male ratios varying from 2:1 to 10:1. [19, 20]

Body dysmorphic disorder

Diagnostic criteria is as follows:

A.  Preoccupation with one ore more perceived defects or flaws in physical appearance that are not observable or appear slight to others.

B. At some point during the course of the disorder, the individual has performed repetitive behaviors (checking, grooming, reassurance seeking) in response to their concerns.

C.  The preoccupation causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

D.  The appearance preoccupation is not better explained by concerns with body fat or weight in an individual whose symptoms meet diagnostic criteria for an eating disorder.

Complaints include preoccupations with the face, head, hair, skin, genitals, breasts, buttocks, extremities, shoulders, and overall body size or weight. The nose, ears, face, or sexual organs are involved most often. [21] Concerns of patients with BDD, unlike those of patients with illness anxiety disorder, are limited only to bodily appearance, not underlying illness.

Mood disorders

Depression may be considered in these patients because they often present with somatic symptoms, somatic ruminations, and illness anxiety preoccupation. However, for a diagnosis of depression, patients must have depressed mood or anhedonia (loss of interest or pleasure in activities) and must have 4 associated symptoms, including any of the following: poor appetite or overeating, insomnia or hypersomnia, low energy or fatigue, psychomotor agitation or retardation, poor concentration or indecision, feelings of worthlessness or excessive guilt, or thoughts of death and/or suicide. The patient's appearance is usually consistent with these problems. When depression is treated, the somatic complaints also resolve.

Anxiety disorders

These disorders are part of the differential diagnosis for hypochondriasis because patients often present with, or have a number of, somatic symptoms. Typically though, the somatic symptoms are alleviated when these disorders are treated. Patients with generalized anxiety disorder have excessive, pervasive, and uncontrollable worries concerning relationships, work, and leisure. However, such worries are generalized and are not limited to worries of being ill. Patients with OCD have obsessions that mimic illness anxiety in that they are recurrent and persistent and experienced as intrusive, but these worries extend beyond concerns about illness (eg, to fear about a door being unlocked) and are often accompanied by thematically related compulsive compensatory behavior (eg, lock checking).

On the other hand, OCD may be comorbid with illness anxiety disorder. Based on family data in studies of OCD, Bienvenu et al found a relationship between OCD and hypochondriasis and body dysmorphic disorder, suggesting comorbidity between OCD and these disorders. [22] Van den Heuvel et al found similar frontal-striatal alterations during a planning task among OCD, panic disorder, and hypochondriasis, suggesting a common limbic activation pathway among these disorders. [23]

Psychotic disorders

A patient with a psychotic disorder (eg, schizophrenia, delusional disorder) may present primarily with a somatic symptom, but the belief has a fixed quality (ie, a delusion) in contrast to the patient with illness anxiety disorder, who is convinced of his or her concerns but is able to consider the possibility that the specific feared disease is not present. Monosymptomatic hypochondriacal psychosis is a term that was commonly used to indicate concerns about delusional parasitosis, or the delusions of infestation by parasitic organisms. Now these patients are generally thought to have delusions (ie, diagnosed formally as DSM-5 delusional disorder, somatic type).

Personality disorders

Some personality disorders/styles overlap with illness anxiety disorder. [14] Characteristics of patients with illness anxiety include anxiousness, conscientiousness, dependence, narcissism, and avoidance. [24] In a study that compared personality disorder of patients with hypochondriasis with obsessive-compulsive disorder (OCD) and social anxiety disorder (SAD), the amount of personality disorder comorbidity was not significantly different. The most common personality disorders comorbid with hypochondriasis were paranoid (19.4%), avoidant (17.7%), and obsessive-compulsive (14.5%). [25]

Primary care

As detailed above, the patient's report of his or her physical symptoms may not be specific, and the physical examination may not support a clear medical diagnosis. A history of “doctor shopping” is common. Because multiple evaluations and workups have been unfruitful, frustration may ensue, as the patient feels the physicians do not care. The task of the primary care physician here involves the development of a caring and professional relationship with the patient and setting realistic expectations. The physician must be firm but supportive to avoid the patient fleeing to another physician. [26]

Some of the "tests" patients present are predictable. Often, the patient requests a specific blood test, radiological study, or invasive procedure, or a combination thereof. The patient may question the expertise of the primary physician and request referrals to different specialists and an ongoing workup. Any possible yield of an investigation must be balanced by the potential medical risks as well as the psychological risk of reinforcing the cyclical illness anxiety/reassurance seeking pattern. The physician should engage the patient in the decision-making process whenever possible. Premature reflexive reassurance may be interpreted as a physician deflecting responsibility or may serve to feed into the patient’s reassurance-seeking behavior. [27] Meanwhile, the physician must not lose sight of more important health care maintenance examinations, annual screening studies, and lifestyle modifications. [26]


Illness anxiety, per se, is infrequent in the pediatric population because of children’s lack of knowledge of specific disorders that may engender concerns or fears. Children generally respond to reassurance from parents and health care professionals. [26] On the other hand, somatic disorders as a result of psychological distress do occur (eg, headaches, stomachaches). In childhood, recurrent abdominal pain (RAP) is a common reason for medical consultation, in at least 1 out of 10 school-aged children. The outcomes of RAP among 28 young adults showed higher ratings on the Hypochondriacal Beliefs subscale of the Illness Attitude Scales (IAS). [28] As adults, these patients also perceived themselves as more susceptible to illness and expressed more fear of death. A history of childhood somatic symptoms and psychosocial distress appear to increase the risk of hypochondriasis in adulthood. [29]

Several factors may increase the risk for illness anxiety presentations. Somatic disorders seem to occur more in children who are conscientious, sensitive, insecure, and anxious. Childhood adversity, especially overt neglect and sexual abuse, are associated with frequent medical consultations. [30] Interestingly, childhood memory about health may contribute to the development of illness anxiety, though these children may not distinguish between memories about their own health and the health of a friend or stranger. [31] As children develop a better ability to communicate and more awareness of their emotions, the expression of emotion through somatic symptoms lessens.


The diagnosis of illness anxiety can be particularly challenging in this patient population, since elderly patients may experience both medical and psychiatric disorders as part of aging. Most elderly patients are reluctant to admit to sadness or depressed mood. Instead, the depressive symptoms are expressed somatically. Additionally, an elderly patient is uniquely faced with loss of loved ones, social isolation, reduced financial resources, restricted freedom, and existential crisis. The illness anxiety reaction is often an adaptive response to such unfamiliar psychosocial distress. [33]  Illness anxiety may also be difficult to distinguish from reality-based organic diseases, psychiatric disorders, or adjustment to psychosocial changes. [32] Providers should empathize with the functional value of illness anxiety in the elderly patient in helping the patient face mounting medical problems and inevitable aging.

Chronic pain

Illness anxiety is associated with chronic pain. This has been studied in an evidence-based structured review of 57 studies that examined the relationship between hypochondriasis or somatization and chronic pain. In some patients, illness anxiety may develop after development of the disorder causing the pain. The more severe the pain, the higher the likelihood that illness anxiety may develop. In some studies, treatment of pain may improve the severity of hypochondriasis. [34]

Other specialties

Illness anxiety is now being directly or indirectly evaluated in numerous specialties, including cardiology, dermatology, otorhinolaryngology, gastroenterology, infectious disease, obstetrics and gynecology, ophthalmology, and oncology. [26]

Differential Diagnoses