Understanding and Managing Anxiety Sensitivity During Critical Illness and Long-Term Recovery

Anxiety sensitivity is the fear of experiencing symptoms and sensations associated with anxiety.^1,2  Conceptually, anxiety sensitivity is the intolerance or catastrophic appraisal of anxiety-related sensations, which then serves to exacerbate such sensations, leading, in turn, to maladaptive escape and avoidance behaviors.²  Thus, anxiety sensitivity is an essential factor in the experience of psychological distress and related maladaptive behaviors, including those that may be detrimental to health.^3,4 

Anxiety sensitivity is a significant predictor of psychopathology and related maladaptive behaviors.²  Meta-analyses have provided strong support for the relationship between anxiety sensitivity and anxiety-related disorders, particularly posttraumatic stress disorder (PTSD), panic disorder, and suicidal ideation.^5,6  Anxiety sensitivity has also been linked to chronic illness (eg, asthma, cardiovascular disease, chronic pain) and problematic health behaviors (eg, nonmedical benzodiazepine use, tobacco use, lower exercise engagement, medication nonadherence).^2,4,7–10  Not only do these consequences cause distress and impairment in those with anxiety sensitivity, but they also increase the burden on the health care system, as anxiety sensitivity is associated with increased emergency room visits and other health care use.¹¹  Because anxiety sensitivity is associated with multiple negative individual and organizational outcomes, it is considered an important psychological and behavioral condition shared across different types of health disorders (ie, a transdiagnostic factor).

Anxiety sensitivity is applicable to acute and critical illness when the patient experiences unpleasant sensations such as pain, shortness of breath, nausea, and thirst. Although the role of anxiety sensitivity has been examined less in individuals with critical illness than in other populations, higher anxiety sensitivity may lead the critically ill patient to avoid activities that are feared to potentially increase anxiety-related sensations, thereby affecting the delivery of critical care interventions (eg, physical or occupational therapy, repositioning, and weaning from sedatives or mechanical ventilation). After critical illness, the patient may disengage from follow-up services owing to fear of revisiting distressing feelings associated with the intensive care unit (ICU) admission, decline to participate in physical therapy because of a fear of pain, or not report symptoms of post–intensive care syndrome such as anxiety, depression, and PTSD for fear of being negatively perceived by others.

It is important for ICU clinicians to adopt strategies to differentiate a “true alarm,” or sensations that require medical intervention, from a “false alarm,” or anxiety symptoms that require a psychological intervention. For instance, patients having difficulty with weaning from mechanical ventilation should undergo a detailed workup to search for underlying medical causes (eg, upper airway resistance, cardiac dysfunction, diaphragmatic insufficiency) before anxiety sensitivity is identified as the primary cause. Moreover, fear and anxiety commonly result from ICU delirium, which should be ruled out or managed before the patient is diagnosed with and treated for anxiety sensitivity, as delirium precludes the patient’s proper understanding of circumstances and learning new information. In this review, we explore the concept of anxiety sensitivity across the trajectory of critical care, propose a role for ICU clinicians in the identification and management of anxiety sensitivity through the use of strategies to engage patients and care partners, and discuss future directions for critical care research.

Anxiety sensitivity has been described as a fear of anxiety symptoms that incorporates false beliefs about the harmfulness of such symptoms.¹²  Just as individual susceptibility to anxiety varies (one person may become anxious with minimal provocation, whereas another may do so only under the most stressful circumstances), so does susceptibility to anxiety sensitivity. An individual’s sensitivity to anxiety plays a key role in the maintenance of anxiety-related disorders (eg, panic disorder, social anxiety disorder) and avoidance behaviors (eg, substance abuse, social withdrawal, declining medical interventions). Meta-analytic reviews have demonstrated strong associations between anxiety sensitivity and anxiety-related disorders, particularly panic disorder and PTSD.^5,13  The domains of anxiety sensitivity (physical, social, and cognitive concerns) are also differentially associated with anxiety-related disorders. For example, the physical concern dimension of anxiety sensitivity is associated with panic disorder and health anxiety, whereas the cognitive concern dimension has been found to be greater among those with comorbid PTSD and generalized anxiety disorder.^14,15 

In the Zvolensky framework,²  anxiety sensitivity serves as an intensifying factor in interpreting physiologic responses (eg, increased heart rate, tachypnea) in combination with cognitive catastrophizing (eg, “This must mean I am having a heart attack”), leading to exacerbation of anxiety and panic. Research on the assessment and treatment of anxiety sensitivity is expanding to address the implications of treating the disorder in the context of anxiety and highly distressing situations.

Anxiety sensitivity is most often measured using the validated Anxiety Sensitivity Index (ASI) and, most recently, the ASI-3.^1,16  The ASI-3 is an 18-item scale that addresses physical, cognitive, and social concerns individuals may have regarding their anxiety. Each item is scored from “very little” to “very much.” Higher scores indicate greater anxiety sensitivity, with a score of 18 or lower indicating very little fear of anxiety-related sensations. Below are ASI-3 statements with examples of related thought and behavior patterns.

It scares me when my heart beats rapidly. Example: “I’m having a heart attack.”

It scares me when I am unable to keep my mind on a task. Example: “I’m afraid I will forget what I am doing and fall, so I tell the physical therapist I don’t want to stand.”

I worry that other people will notice my anxiety. Example: “When I get scared and short of breath, I’m afraid people are going to notice and not take my medical problem seriously.”

During hospitalization for critical illness, observable signs of anxiety sensitivity may include asynchrony with the ventilator, tachypnea, tachycardia, or expressions of anxiety or agitation in the absence of physiologic explanations. Patients may also require significant staff time. Similarly, during long-term recovery from critical illness, patients with anxiety sensitivity may need increased assessment time, extra explanation and demonstration before participating in physical therapy, and reassurance of safety when experiencing physical discomfort. When asked about fears during the phase after critical illness, a patient may express being afraid of having a heart attack or being unable to breathe, people noticing or evaluating them negatively (particularly in relation to previously independent activities such as toileting), losing control of one’s mind (especially in those who experienced delirium), becoming a burden on family members, being unable to work, or dying alone.

Four concepts underpin the etiology of anxiety sensitivity. First, genetics may contribute to the condition, with a heritability estimate of 45%.^17,18  Second, parental responses to childhood illness or injury may reinforce attending to and misinterpreting anxiety symptoms.¹⁹  Third, a history of unexpected panic attacks increases the likelihood of anxiety sensitivity.^20,21  Finally, stressful life events are associated with anxiety sensitivity.^18,22 

Patients with critical illness frequently experience anxiety and fear due to a heightened volume and intensity of physiologic cues and other stressors, with nearly 50% of ICU patients having clinically significant anxiety symptoms during their ICU stay.²³  Common stressors during critical illness and hospitalization include loss of control and independence, pain, delirium, sensory deprivation, social isolation, and imminent death. Physiologic symptoms such as breathlessness, fatigue, procedural and positional pain, and dizziness associated with hypotension may be viewed by patients as potentially deadly, rather than strange but expected features of recovery. Invasive medical procedures such as mechanical ventilation and placement of indwelling urinary catheters, chest tubes, intravenous catheters, and other tethers can trigger significant anxiety and thus pose special challenges for patients with anxiety sensitivity. Finally, several medications that play important roles in critical care, including steroids and vasopressors, may be associated with increased anxiety and agitation.²⁴  These symptoms may be greatly exacerbated in patients with premorbid anxiety sensitivity.^25,26 

Experiencing a critical illness itself commonly induces fear. Critically ill patients have one or more complex acute and chronic health conditions (eg, organ failure, diabetes, heart disease) requiring close monitoring of physiologic changes, medications, and diet. In addition, patients may associate physiologic changes with past experiences requiring hospitalization. For example, if a patient experienced an increased heart rate just before receiving a shock with an internal defibrillator, they may associate heart rate changes with intense fear of another shock, causing them to avoid behaviors resulting in heart rate changes. In a study of patients with chronic obstructive pulmonary disease, after accounting for depression and anxiety, physical symptoms associated with anxiety sensitivity were significant predictors of disease symptom exacerbations and an increased incidence of emergency room visits and hospitalizations.²⁷ 

After hospitalization, ICU survivors often struggle with anxiety and PTSD.²⁸  Some patients report not wanting to leave the hospital for fear of getting sick again, and others describe not seeking important medical care to avoid reminders of hospitalization. The physical distress, loss of control, and disorientation associated with critical illness can manifest as long-term physical and psychological trauma and vulnerability. Stressors in the context of new or worsening chronic conditions during long-term ICU recovery may include physical deconditioning, cognitive impairment, depression, medication access challenges, increased health care use, and use of durable medical equipment.²⁹  Potential anxiety sensitivity triggers may include sounds (eg, microwave timers that sound like ventilator alarms), nightmares, changes in voice or swallowing due to laryngeal injuries from endotracheal intubation, or the need for mobility aids (eg, cane, walker) to resume walking. Surviving an ICU stay often involves psychological, cognitive, and physical difficulties as patients and care partners navigate the implications of recovery and face the need for adaptations for the patient to resume pre–critical illness activities and routines.^30,31 

Anxiety sensitivity has been found to be not only an integral aspect of many anxiety and mood disorders but, specifically, a strong mediator and mechanism of change in treatment outcomes, indicating that it should be considered a treatment target.^32,33  Anxiety sensitivity has been shown to improve with treatment for a diagnosed mental health disorder, such as cognitive behavior therapy (CBT) for panic disorder.^34,35  Because of the prevalence of anxiety sensitivity across mental health disorders, treatments targeting anxiety sensitivity are widely applicable to treatments for multiple mental health concerns, such as depression, PTSD, and panic disorder.

Brief structured treatments for individuals with high anxiety sensitivity at risk for the development of psychopathology have shown promising results.^31,34,36  Anxiety sensitivity–specific treatment drawn from traditional CBTs includes psychoeducation, cognitive restructuring, interoceptive exposure, and situation exposure.^35,37  The Unified Protocol for Transdiagnostic Treatment of Emotional Disorders has also been used to treat anxiety sensitivity, with interoceptive exposure highlighted as the most effective component.³⁸  Psychoeducation focuses on normalizing anxiety and its related sensations, whereas interoceptive exposure involves intentionally inducing anxiety-related sensations to demonstrate to the patient that experiencing these sensations will not lead to catastrophic outcomes.³⁹  Cognitive bias modification is an intervention that prompts individuals to focus on positive information and experiences rather than negative experiences that give rise to anxiety sensitivity. Treatment for anxiety sensitivity in an ICU setting (ie, psychological first aid) is different from that in traditional outpatient settings involving formal psychiatric diagnosis (eg, CBT for panic disorder). Whereas traditional CBT often occurs in 8 to 12 sessions, brief treatment for anxiety sensitivity may be implemented in as little as 1 session.³⁶  Treatments for anxiety sensitivity have shown efficacy in reducing not only anxiety sensitivity but also smoking, alcohol and opioid use, anxiety and depression symptoms, and suicidal ideation.^37,40–43  Assessment tools such as the ASI-3 can be used to identify the primary domain of anxiety sensitivity distress (physical, social, or cognitive) to help tailor treatment.

Although methods for the assessment and management of anxiety during the critical illness trajectory are well established,²⁶  research specific to anxiety sensitivity is limited. Further investigation is needed of clinical implications and interventions during and after critical illness. Patients with anxiety sensitivity may experience increased distress when undergoing medical interventions, such as mechanical ventilation or invasive procedures, which can trigger fears of experiencing the physical symptoms of anxiety. Therefore, ICU clinicians should be aware of patients’ possible anxiety sensitivity so that they can use clear communication and implement pain management or relaxation techniques to mitigate distress and improve patient outcomes.

A thorough medical evaluation is typically necessary to differentiate between anxiety sensitivity and other medical conditions. Anxiety sensitivity can coexist with other medical conditions, and in some cases the physical symptoms may be caused or exacerbated by anxiety. Therefore, a comprehensive evaluation in which both physical and psychological factors are considered is often necessary for effective symptom management. However, communication barriers due to mechanical ventilation and delirium can inhibit assessment of anxiety sensitivity with validated tools during critical illness. Therefore, management relies largely on reducing stressors through environmental modification to minimize anxiety sensitivity triggers.

Providing basic psychoeducation to ICU patients on common physiologic and psychological symptoms may temper anxiety sensitivity. For example, the clinician can tell the patient, “It’s normal to feel scared when you are short of breath. You are getting better, so this shortness of breath is typical and uncomfortable, but not deadly.”⁴⁴  It can also help to provide education about ICU delirium and the process of resolution as well as reassurance that this is not a new, permanent psychiatric condition. Helping patients identify aspects of recovery within their control may reduce anxiety and increase engagement during critical illness (eg, timing of physical therapy, type of music played, communication tools used).

Evidence-based strategies for reducing stressors and minimizing anxiety sensitivity triggers include family visitation and involvement to reduce social isolation, adjusting sensory stimuli to promote a comfortable and calming environment (eg, reducing noise levels), promoting sleep-wake balance, fostering clear and timely communication, and music therapy.^45,46  When a patient is experiencing an anxiety sensitivity crisis and is in need of more urgent intervention, psychological first aid can be provided (Table 1). Psychological first aid helps the patient to feel safe, connected, and supported through practical and emotional assistance.⁴⁷  Psychological first aid may include assuring the patient of their safety, listening actively to concerns, using calming techniques such as hand-holding or breathing exercises, or providing distraction. For example, if a patient is hyperventilating, the nurse can suggest that they close their mouth, as it is very difficult to hyperventilate with a closed mouth. If time permits, the patient can be coached in paced breathing (eg, inhale for 3 seconds and exhale for 5 seconds) for 3 minutes. These activities can provide the patient with an added sense of control.

Family engagement for managing anxiety sensitivity requires awareness of anxiety sensitivity, its triggers, and how to recognize and manage patient symptoms. Family members can be encouraged to help identify root issues (eg, tubes, catheters, loss of control, previously feared triggers) and provide information on ICU treatments and equipment to help the patient gain a sense of control. They can also provide important information about what helps the patient feel safe and relaxed in their day-to-day life (eg, music preferences, relaxing touch, pleasurable activities). In some cases, family members may be encouraged to bring in comforting or familiar objects from home. Moreover, those who are interested can take an active role in patient care by helping with basic activities of daily living (eg, grooming) and physical therapy (eg, range-of-motion exercises), which may provide the patient with a sense of comfort and familiarity.^48,49  Family members can also work with ICU clinicians and patients to set goals for ICU treatment and recovery to ensure collaborative decision-making and patient empowerment.

Psychological first aid offered during inpatient hospitalization is not a long-term solution for anxiety sensitivity. Patients may be fearful that the breathing exercises practiced during hospitalization will not work after hospital discharge. After robust physical assessments are performed to rule out any ongoing physiologic issues, ICU recovery clinics and peer support programs can incorporate anxiety sensitivity assessment and management to promote patients’ overall well-being. Within the multidisciplinary ICU recovery clinic or peer support setting, psychoeducation can be provided about the nature and causes of anxiety and panic. Psychologists or social workers embedded in ICU recovery programs can describe how the sympathetic nervous system is triggered, causing changes to occur in the body that are designed to alert the person to danger and protect them from harm. This sympathetic response is meant to feel uncomfortable for the purpose of motivating the individual to act, and is akin to a fire alarm that alerts one to leave the building. Content areas for psychoeducation materials are described in Table 2. Given that anxiety was one of the few objective constructs that did not improve in recent research on the effectiveness of a complex intervention for ICU survivors,⁵⁰  the integration of anxiety sensitivity assessment and management may be crucial for future practice in this area.

Interoceptive exposure is a CBT technique in which the patient is deliberately exposed to bodily sensations associated with anxiety sensitivity triggers in a controlled and gradual manner to reduce fear and anxiety.³⁹  Through this exposure, the patient can better differentiate between true and false alarms and therefore know when a hospital visit is warranted versus when the symptoms are due to anxiety. For each anxiety sensitivity sensation, different exposures can be simulated (eg, hyperventilation, tachycardia), when not contraindicated, to trigger anxiety sensitivity and perform in-the-moment cognitive modification (Table 3). The brain knows that the sensation is due to anxiety, but the limbic system does not. The interoceptive exposure process can help the patient acknowledge that the amygdala set off an alarm, but also that the patient (1) is afraid of having a heart attack, (2) is not having a heart attack, and (3) is not dead.

Critical care research needs related to anxiety sensitivity across inpatient and outpatient settings include measurement and intervention development. Population-level incidence and prevalence reports are needed to interpret the significance of anxiety sensitivity in the critical illness trajectory. Risk factors for anxiety sensitivity may include the types of invasive tubes and catheters used, sleep disruption, characteristics of acute illness, and ongoing biological mechanisms such as hyperinflammation. Assessment measures could be pilot tested for validity and acceptability with ICU patients and survivors and used in tandem with qualitative description of the patient experience of anxiety sensitivity and what helps to reduce symptoms. Protocolized intervention methods are needed to establish cause-and-effect relationships for patient-centered anxiety sensitivity management, with corresponding feasibility studies to assess implementability, safety, and efficacy. Longitudinal studies examining interventions are warranted to evaluate short- and long-term efficacy. Addressing anxiety sensitivity research priorities could improve outcomes for individuals with anxiety sensitivity during and after critical illness. Last, education and dissemination of knowledge are fundamental to increasing clinician awareness and assessment of anxiety sensitivity during and after critical illness.

Understanding the prevalence and characteristics of anxiety sensitivity in ICU survivors is crucial to improving their experience of critical care. A “fear of fear” can amplify anxiety during all stages of the critical illness trajectory, from ICU admission through long-term recovery. Accurate detection and effective interventions in the inpatient and outpatient settings are integral to comprehensive critical care. Future research should incorporate anxiety sensitivity assessment and management techniques across the critical care recovery continuum.

The contents of this article are solely the responsibility of the authors and do not necessarily represent the views of the Department of Veterans Affairs (VA), the US government, or the National Institutes of Health (NIH).