Anxiety is a fundamental aspect of the human experience. It can be an adaptive response to a perceived threat, with both psychological and physiological features. In the short term, anxiety can be a motivator and prepare one to confront a crisis. When anxiety persists or occurs abnormally, it can impair functioning and lead to an anxiety disorder. In the medical setting, anxiety can be a normal coping mechanism when dealing with the stress of illness. However, if it exceeds social, psychological, or physiological needs, anxiety can become maladaptive—leading to somatic symptoms that cause distress and impairment.
Prevalence of anxiety in the medically ill
Patients with primary anxiety disorders, such as generalized anxiety disorder (GAD), panic disorder, and phobias, as well as PTSD, report a higher rate of certain medical illnesses than are observed in the general population. The National Comorbidity Survey Replication showed a 12-month prevalence rate of 3.1% for GAD and a lifetime prevalence rate of 5.7%; the lifetime prevalence for panic disorder was found to be 4.7%, with a 12-month prevalence of 5.7%.1 In comparison, the general prevalence of GAD in primary care is thought to be 8%.2 Findings from Fleet and colleagues3 suggest that an estimated 25% of 441 chest pain complaints in an emergency department (ED) setting were due to panic attacks.
Specific medical phobias, such as fear of blood, needles, or MRIs (due to claustrophobia), are quite common. Combined blood-injectioninjury phobias have been found to have a lifetime prevalence of over 3% in a general population sample.4 The presence of these phobias is of concern because they can contribute to patients having difficulty in pursuing medical care.
The lifetime prevalence of PTSD is 6.8%, with a 12-month prevalence estimated to be 3.5% in the general population.1 In a primary care setting, 12% of patients examined were found to have PTSD5; 30% to 40% of motor vehicle accident survivors were found to have PTSD, so were 20% to 45% of burn victims.6 The diagnosis of an acute distress disorder strongly predicted the presence of PTSD 6 months later.7 Although PTSD and acute stress disorder are categorized under trauma and stressor-related disorders in DSM-5, in this article, PTSD is considered as a primary anxiety disorder.
Impact of anxiety disorders on medical illness
Anxiety disorders cause diminished functioning and well-being along with increased suffering; these effects are amplified in the presence of comorbid medical illness. As a group, they contribute to symptom severity in medical populations, functional impairment, and increased risk of disease progression. Anxiety also plays a role in increased health care use and cost, greater number of iatrogenic complications, and decreased adherence to treatment.
Beyond psychosocial implications of anxiety disorders, there are also physiological effects of anxiety. Anxiety can create excessive sympathetic activation, alteration in inflammatory response, and disruption of the hypothalamic-pituitary-adrenal axis—predisposing patients to increased health risks. Comorbid anxiety disorders and medical illnesses often lead to a self-perpetuating cycle in which a chronic medical illness negatively affects level of function, leading to depression and anxiety, which, in turn, can worsen the underlying medical condition. The dynamic interplay between comorbid anxiety disorders and medical illnesses can pose diagnostic and management challenges.
Primary anxiety disorders and comorbid physical illnesses
Patients with primary anxiety disorders are more likely to suffer from GI, respiratory, cardiac, and neurological disorders, even after adjusting for confounding factors such as sex, depression, and substance use disorders. Among patients with panic disorder, GAD, and PTSD, rates of irritable bowel syndrome are much higher than in those with no psychiatric diagnoses. Similarly, panic disorder, GAD, and phobias are strongly associated with asthma and cancer. Anxiety disorders are associated with an increased incidence of cardiovascular disease, such as myocardial infarction, angina, sudden cardiac death, and hypertension, and frequent panic attacks are associated with worse cardiac outcomes. PTSD is associated with increased risk of cardiovascular disease, increased rates of re-hospitalization, and decreased adherence to treatment regimens. Primary anxiety disorders, particularly panic disorder, are also comorbid with seizure disorder. Finally, social anxiety disorder and panic attacks are often seen in patients with Parkinson disease.8
Secondary anxiety and secondary anxiety disorders
Since there is a bidirectional relationship between anxiety and medical illnesses, many severe medical conditions can lead to secondary anxiety that ranges from normal psychological reactions to illness to intense anxiety or preoccupation about somatic sensations, which result in impaired functioning. A diagnosis of a severe, chronic, or debilitating medical illness will invariably elicit a number of negative emotions, such as anxiety, fear, sadness, and anger. When the emotional reactions are out of proportion to the context and lead to significant impairment in functioning, secondary anxiety disorder (ie, adjustment disorder with anxiety) can be the result.
Dr Dong is Assistant Professor of Psychiatry at INOVA Fairfax Hospital in Falls Church, Va. Drs Noorani and Vyas are Psychiatry Residents in the department of psychiatry and behavioral sciences at The George Washington University, in Washington, DC. Drs Balgobin and Torres-Llenza are Psychosomatic Medicine Fellows at INOVA Fairfax Hospital and The George Washington University. Dr Crone is Associate Professor of Psychiatry at INOVA Fairfax Hospital and The George Washington University. The authors report no conflicts of interest concerning the subject matter of this article.
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