Illness Anxiety Disorder Fast Facts

Illness anxiety disorder (IAD) is a mental disorder in which a person has persistent anxiety about having a serious illness despite the absence of symptoms.

IAD was previously known as hypochondria or hypochondriasis.

IAD affects about a tenth of a percent of people in the United States.

IAD sometimes fluctuates in severity, and stress may make the condition worse.

United Brain Association

IAD was previously known as hypochondria or hypochondriasis.

What is Illness Anxiety Disorder?

Illness anxiety disorder (IAD) is a mental disorder in which a person experiences extreme anxiety related to perceived physical symptoms or illnesses even when no physical disorder is present. People with IAD are afraid that they are seriously ill or have some other kind of significant physical problem. Often, they have no physical symptoms, or they interpret normal body functions or sensations as signs of illness.

Some people with IAD persistently seek medical care for their misperceived symptoms, and they may subject themselves to unnecessary tests and procedures. Other people with IAD have a mistrust of medical professionals and avoid seeking care.

IAD was formerly known as hypochondriasis or hypochondria, but health professionals no longer use those terms.

Symptoms of Illness Anxiety Disorder

Common signs of IAD include:

  • Extreme anxiety related to health issues
  • Fixation on researching illnesses
  • Excessive attention paid to body functions such as heart rate, blood pressure, or temperature
  • Avoidance of situations seen as risky in terms of health, such as crowds or social events
  • Exaggeration of physical symptoms
  • Discomfort with normal body functions
  • Often talking about health issues and seeking reassurance

Related Disorders

The signs of IAD may look like those of other disorders, but those other disorders differ in important ways. Conditions with similar features include:

  • Somatic symptom disorder (SSD). This disorder can also feature an anxiety-producing fixation on physical health symptoms that don’t have a discernible cause. However, the physical symptoms in SSD are real and not imagined.
  • Conversion disorder. This disorder is characterized by neurological symptoms that have no identifiable physical cause. However, as in SSD, the symptoms of conversion disorder are real and not imagined or exaggerated.

What Causes Illness Anxiety Disorder?

The cause of IAD is unknown. It is likely triggered by a combination of factors, including biology and external environmental events. Some factors seem to put a person at increased risk for IAD. Possible risk factors include:

  • Having a severe illness in childhood or having a close family member who is seriously ill
  • Having family members with excessive health-related anxiety
  • Having a health scare, such as the possibility of cancer that is later ruled out
  • History of mental health disorders such as depression or anxiety
  • History of abuse or neglect
  • Periods of extreme stress
  • Traumatic experiences (e.g., rape, violent crime, or domestic abuse)

Is Illness Anxiety Disorder Hereditary?

People with a family history of anxiety disorders have a higher risk of developing anxiety disorder themselves, suggesting an inherited component to anxiety. However, scientists have not identified a single gene definitively associated with separation anxiety or other anxiety disorders. Instead, anxiety is likely the result of a coincidence of multiple genetic and environmental factors.

How Is Illness Anxiety Disorder Detected?

Early detection of IAD is important because prompt treatment of the disorder may help the sufferer avoid significant consequences in the future. Worrying about physical health is normal, but worries that persist after a medical professional assures you there is no need for anxiety are a cause for concern. IAD is often first diagnosed when health-related fears impair the sufferer’s ability to function, and people around the sufferer begin to notice the impairment.

How Is Illness Anxiety Disorder Diagnosed?

Diagnosis of IAD begins by ruling out medical problems that may be causing symptoms. After these exams, if the doctor suspects that IAD or another mental disorder is the cause of the symptoms, they may recommend a psychological or psychiatric assessment.

Diagnostic steps may include:

  • A physical exam. This exam will rule out physical conditions that could be causing the symptoms.
  • Psychological assessments. These assessments may take the form of questionnaires or talk sessions with a mental health professional to assess the patient’s mood, mental state, and mental health history. Family members or caregivers may also be asked to participate in these assessments.

After medical causes are ruled out, medical professionals can consider whether the patient meets the diagnostic criteria for IAD. These criteria include:

  • Persistent thoughts, worry, or anxiety about having or acquiring a serious illness.
  • Few physical symptoms, if any, are present.
  • The person has general anxiety about health-related issues.
  • The person is fixated on monitoring their health status.
  • The anxiety has lasted at least six months.
  • Any other mental condition does not better explain the symptoms.


How Is Illness Anxiety Disorder Treated?

There is no cure for IAD. Psychotherapy, usually cognitive behavioral therapy, is the most common course of treatment. Medications may help symptoms of IAD and those of other co-existing disorders, such as depression or anxiety. Serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed medications.

How Does Illness Anxiety Disorder Progress?

With treatment, some people with IAD see significant improvement. Untreated IAD may last indefinitely, and symptoms may periodically resolve and then reappear later. The symptoms can cause impairments that produce severe complications. Long-term complications can include:

  • Depression or other mental disorders
  • Social isolation
  • Lack of healthy interpersonal relationships
  • Work difficulties or unemployment
  • Financial difficulties

How Is Illness Anxiety Disorder Prevented?

There is no known way to prevent IAD. However, prompt treatment may relieve the effects of the disorder and make it less likely that the sufferer will experience severe complications over time.

Illness Anxiety Disorder Caregiver Tips

Many people with illness anxiety disorder also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with IAD:

  • More than half of people with IAD also suffer from depression.
  • Many people with IAD have a co-existing anxiety disorder, such as generalized anxiety disorder or a phobia.
  • Other commonly comorbid disorders include personality disorders and obsessive-compulsive disorder (OCD).

Illness Anxiety Disorder Brain Science

Scientists believe that anxiety symptoms come from activity in the parts of the brain that control emotions and our reactions to them. These parts of the brain are called the limbic system. The limbic system is associated with anxiety in several ways:

  • The amygdala, the part of the brain responsible for detecting threats, may be hyperactive and may misidentify causes for fear or worry when none exist.
  • An overactive amygdala may persistently cause the hypothalamus to trigger the hormonal response that produces the physical symptoms of anxiety.
  • Communication between the amygdala and the prefrontal cortex (PFC) may be impaired. The PFC is responsible for triggering a rational response to threats, and it may not be able to do so when it is unable to communicate with the amygdala effectively.
  • The hippocampus, the part of the brain responsible for processing long-term memory, may be underdeveloped or dysfunctional in the case of anxiety. As a result, it may prefer to retain stress-related memories rather than more rational ones. 

Illness Anxiety Disorder Research

Title: Study of Dextromethorphan in OCD and Related Disorders

Stage: Not Yet Recruiting

Principal investigator: Peter J. van Roessel, MD PhD

Stanford University

Palo Alto, CA

The purpose of the study is to assess the tolerability and efficacy of dextromethorphan in combination with fluoxetine for symptom relief in OCD and related disorders.

Obsessive-compulsive disorder (OCD) and the related disorders body dysmorphic disorder (BDD), somatic symptom disorder (SSD), and illness anxiety disorder (IAD) are psychiatric conditions characterized by recurrent, intrusive thoughts, feelings or images (obsessions or preoccupations) and repetitive or ritualized behaviors or avoidance performed to relieve obsession or preoccupation-related anxiety. They are a significant cause of mental health-related disability and are inadequately served by available treatments.

This study tests whether an over-the-counter cough suppressant medicine, dextromethorphan, may offer symptom relief when combined with a low dose of fluoxetine, a standard prescription treatment for OCD and related disorders.

Title: Caloric Vestibular Stimulation for Modulation of Insight in Obsessive-Compulsive Spectrum Disorders

Stage: Recruiting

Principal investigator: Peter J. van Roessel, MD, PhD

Stanford University

Palo Alto, CA 

Obsessive-compulsive and related disorders (OCRD), including obsessive-compulsive disorder and body dysmorphic disorder, are chronic and disabling conditions characterized by recurrent intrusive thoughts and associated compulsive behaviors that affect millions of individuals in the US each year. Individuals affected by OCRD differ in insight or the degree to which they understand their intrusive thoughts to reflect illness. Impairments in insight limit individuals’ motivation to engage in care and predict worse outcomes in those who access treatment.

This study seeks to explore whether unilateral stimulation of the vestibular system, which activates cortical areas hypothesized to underlie clinical insight, may beneficially modulate insight in individuals with OCRD.


Title: Evaluation of Primary Care Behavioral Health (PCBH) With the Addition of Self-help CBT – A Randomized Multicenter Trial (KAIROS)

Stage: Recruiting

Principal investigator: Viktor Kaldo

Linnaeus University

Vaxjo, Sweden

The overarching goal of primary care is to offer all patients individualized and context-sensitive healthcare with high access and continuity. One of the reasons primary care struggles with this goal is that a large proportion of patients suffer from mental and behavioral health problems, alone or in combination with one or several chronic illnesses. Despite many patients needing psychosocial interventions, there is a lack of mental health professionals and clear pathways for these patients.

Primary Care Behavioural Health (PCBH) is an innovative way of organizing primary care, where mental health professionals have more yet shorter visits, strive for same-day access, and have an active consulting role in the primary care team. To help patients achieve relevant behavioral changes, so-called brief interventions are used based on isolated components from psychological treatments such as Cognitive-Behavioral Therapy (CBT) and Acceptance and Commitment Therapy (ACT). Brief interventions usually stretch over 1-4 treatment sessions. Assessments within the model are generally contextual and largely avoid psychiatric diagnostics, instead focussing on the patient’s situation and their associated coping strategies – whether positive or negative. However, these interventions have not been systematically evaluated in the same way that structured CBT has. There is a risk that patients who would have benefitted from structured CBT and a diagnostic assessment are undertreated due to lack of diagnostics and the reduced visit duration and amount.

Data will be collected at primary care centers (PCCs) that already have high fidelity to a PCBH framework. Fidelity will be measured by an expert group as well as using four questionnaires, one for each of mental health professionals, medical doctors, registered nurses, and leadership. These fidelity scales will be validated in a separate study. In addition to fidelity, work environment and satisfaction with the PCBH implementation will be measured.

Patients at the centers will be randomized between receiving contextual assessments followed by brief interventions or a diagnostic assessment, which can lead to treatment with either self-help CBT (if a treatable diagnosis is confirmed and the patient is suitable for self-help CBT) or brief interventions (if self-help CBT is not deemed to be a suitable intervention). The primary comparison is the outcome for patients who either received self-help CBT or are deemed suitable for the intervention based on screening data. At the same time, secondary analyses will look at treatment outcomes for all patients, including those with non-psychiatric problems such as crises, loss, or work- or family-related issues. The study will also look at implementation outcomes for self-help CBT and diagnostic assessments to see if self-help CBT is a feasible addition to the PCBH model.

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