Claustrophobia

Etiology

Social anxiety disorder is a DSM-V psychiatric condition characterized by an intense fear of social situations and scrutiny—patients who have claustrophobia display a great fear and anxiety of closed spaces. The belief with a social anxiety disorder is that the frontal regions of the brain cannot downregulate amygdalar hyper-activation. The same disruptions in the amygdala-frontal network in social anxiety disorder are attributable to claustrophobia.[7] A meta-analysis of functional brain imaging in specific phobias showed the activated regions of the brain to phobic stimuli were globus pallidus, amygdala, and left insula.[8]

There are two phenomena associated with innate pathological fear, fear sensitization and failure of fear habituation. The amygdala has a decreased threshold activity and decreased potentiation of activity in fear sensitization. Research suggests a dysfunction in the learning-independent fear circuit, which drives defensive behavior without prior learning, in nonexperiential phobias. Habituation is the reduced emotional reaction of a person to repeated stimuli. In fear habituation, the amygdala has decreased habituation.[3]

A single gene defect in the human GPM6A gene is a suspected genetic risk for claustrophobia. The GPM6A gene, expressed in the amygdala and throughout the central nervous system, encodes a stress-regulated neuronal protein found on chromosome 4q32-q34, associated with panic disorder.[9]

Epidemiology

Claustrophobia has a lifetime and 12-month prevalence of 7.7% to 12.5%.[10] There is a higher prevalence of specific phobias in women.[11] Studies conclude that there is a 1 in 10 prevalence of anxiety disorder among people before age 16.[2] A 2007 European study reviewed various studies from different institutions and observed reported rates of claustrophobia among people undergoing MRI ranging between 1% and 15%, with an average of 2.3% of patients needing sedation or being unable to be imaged because of claustrophobia.[12]

History and Physical

Patients with specific phobias report various physical and emotional symptoms. Based on these symptoms, practitioners utilize screening tools to diagnose patients with claustrophobia. Physical symptoms include, but are not limited to, difficulty breathing, trembling, sweating, tachycardia, dry mouth, and chest pain. Emotional symptoms include, but are not limited to, overwhelming anxiety or fear, fear of losing control, an intense need to leave the situation, and understanding the fear as irrational but an inability to overcome it.[13] 

People with claustrophobia tend to feel the fear of what might happen in a confined space which leads to the sense of oxygen not being adequate. Thinking about it or being confined may trigger a fear of being unable to breathe adequately, running out of oxygen, and being restricted. When anxiety levels exceed, the person may begin to experience:

• Sweating and chills
• Increased heart rate and high blood pressure
• Dizziness and lightheadedness
• Dry mouth
• Hyperventilation
• Hot flashes
• Nausea
• Headache
• Numbness
• A choking sensation
• Chest tightness/pain and difficulty breathing
• An urge to urinate
• Confusion

Not all people with claustrophobia will present with all these features, as the presentation can be variable.

Evaluation

Claustrophobia evaluation starts with a patient that presents with the symptom of fear. It needs to be determined if the fear represents a phobia, normal fear, a general medical condition, or an anxiety disorder. Questions in the initial history taking part in the assessment that assesses how the fear impacts the person's development, daily life, and family dynamics are vital to distinguishing anxiety and phobias. For children, sample questions are: How do the child's parents respond to their fear? Can the child or parent recall the exact trigger of the anxiety? Is there any interruption in the child's daily schedule more than three times a day?[14]

Questionnaires are options to evaluate claustrophobia. The Spielberger psychology questionnaire consists of 20 items; each scored from 20 to 80, which measures apparent anxiety.[15] There are three commonly used scales to assess symptoms of anxiety and fear in the younger population: The revised Children's Manifest Scale, the Fear Survey Schedule for Children-Revised, and the State-Trait Anxiety Inventory for Children.[2]

Treatment / Management

The mainstay of management for claustrophobia is cognitive behavioral therapy, in which the patient can discuss negative and distorted beliefs.[16] 

Interoceptive exposure is a form of treatment where the patient gets exposed to the physical sensation of anxiety in a controlled environment.[17] A study reported that interoceptive exposure delivered alone was more helpful to people whose feared outcomes about physical arousal were completely intrinsic and less useful for those whose feared outcomes involved extrinsic components.[18](A1)

Utilizing virtual reality (VR) technology in a stimulating computer-generated atmosphere is one option for treating claustrophobia. Studies have indicated the efficacy of VR tools (apps) in educating patients about MRI and simulating the experience of actually being scanned.[19] The claustrophobia game is an example of both an elevator and magnetic resonance imaging device scenario for closed spaces.[15] The many treatment options for pathological fear have only resulted in about 40% of patients having long-term benefits; most will fail to have complete remission.[3]

Medications may also be used in the management of this phobia. Options include benzodiazepines, selective serotonin reuptake inhibitors, and other investigational drugs (cycloserine, hydrocortisone, quetiapine).[20] Benzodiazepines are the most commonly used pharmacological option for patients with specific phobias that infrequently encounter the unavoidable phobic stimulus.[21] There have been studies on the effectiveness of both escitalopram and paroxetine.[22] Hydrocortisone is a glucocorticoid; endogenous glucocorticoids' mechanism of action is unknown, but what is known is that they are released when a patient is in a fearful situation. A study showed that patients undergoing cognitive-behavioral therapy have an augmented effect with 10 mg of oral hydrocortisone.[23](B2)

Differential Diagnosis

A community survey of 9282 adults residing in the United States showed that the presence of one specific phobia is associated with the prevalence of post-traumatic stress disorder, social phobia, bipolar disorder, generalized anxiety disorder, alcohol dependence, separation anxiety disorder, and major depressive disorder.[24]

Post-traumatic stress disorder (PTSD) is a common disorder that merits consideration in the differential. The main distinguishing reason is the presence of a traumatic event causing PTSD. A specific phobia is not always preceded by a traumatic event (experiential-specific phobia vs. nonexperiential-specific phobia).[3]

Prognosis

Patients with claustrophobia commonly have a chronic course of their anxiety disorder, increasing the risk of other psychopathology.[2] Studies have shown that adolescents with increased phobias had an earlier onset of the disorder. From the same studies, patients with situational and blood-injection-injury-specific phobias were the most strongly associated with indices of impairment and severity.[11] Natural environment phobias correlated with more social problems and increased symptoms of depression and anxiety than animal phobias.[25]

Complications

There is an 83% likelihood of uncovering multiple specific phobias once diagnosed with a particular phobia during a patient's life.[11] Claustrophobia alone generally does not lead to thoughts of self-harm, culminating in suicide. In rare cases, claustrophobia, in combination with depression, anxiety, or any other form of mental health problem, can cause suicidal ideation. In patients needing MRI scans for diagnosis or management, claustrophobia can portend a significant risk as some patients might not be able to go through the procedure despite extra help. In some cases, claustrophobia can restrict the patient's social life, as using elevators, changing rooms, subways, etc., might bring on an episode of panic, leading to a sudden decline.