Panic Disorder

Etiology

Multiple theories and models exist which speak to the possible etiology of the panic disorder itself. Most indicate the potential role of chemical imbalance as a major factor, including abnormalities in gamma-aminobutyric acid, cortisol, and serotonin. It is believed that genetic and environmental factor plays a role in the pathogenesis of panic disorder. Several studies show that adverse childhood conditions may lead to panic disorder in adulthood. Newer research indicates that neural circuitry may have a greater role in panic disorder whereby certain areas of the brain are hyperexcitable in individuals, and that would make them prone to developing the disorder. [5][6]

Some studies show that genetic factors may play a role in the etiology of panic disorder. First-degree relatives have a 40% risk of developing the syndrome if someone in the family already has been diagnosed with the disorder. In addition, patients with panic disorder also have a high risk of developing other mental health disorders.

Epidemiology

Panic disorder has a relatively high lifetime prevalence, ranking behind only social anxiety disorder, posttraumatic stress disorder, and generalized anxiety disorder. Notably, patients suffering from panic disorder have much higher lifetime rates of cardiovascular, respiratory, gastrointestinal, and other medical problems compared to the general population. European Americans are more likely to suffer from panic disorder than African Americans, Asian Americans, or Latinos. Females are more affected than men. Panic disorder peaks in adolescence and early adulthood, with low prevalence in children below the age of 14.[5][7][8]

Patients with panic disorders also share many other comorbidities, including OCD, social phobia, asthma, COPD, irritable bowel syndrome, hypertension, and mitral valve prolapse. Pregnant females with panic disorder are also more likely to have small birth weight infants.

Pathophysiology

Many neurotransmitters and peptides within the central nervous system appear to play a major role in the physical manifestations. Results of brain imaging studies have shown characteristic changes, including increased flow and receptor activity, in specific geographic regions, including the limbic and frontal regions. The amygdala is proposed as the main area of dysfunction. From a pathophysiological and psychological standpoint, medical illness and panic disorder are highly correlated. There are two main theories that attempt to explain why patients are more likely to experience panic attacks. The first hypothesizes that susceptible patients lack the appropriate neurochemical mechanisms, which would normally inhibit serotonin, and this increased serotonin causes alterations in the fear network model of the autonomic nervous system. The second theorizes that a deficiency in endogenous opioids results in separation anxiety and increased awareness of suffocation.[9][10]

History and Physical

The vast majority of patients with panic disorder complain of chest pain, palpitations, or dyspnea on multiple occasions. Other common symptoms may include diaphoresis, tremor, a choking sensation, nausea, chills, paresthesias, or feelings of depersonalization.  Because most patients complain of physical symptoms, they often inquire about alternative explanations of their symptoms not related to mental health. They frequently shy away from care by mental health professionals and, instead, seek reassurance from specialty medical consultants. It is important to remember that conditions such as irritable bowel syndrome, asthma, and vocal cord dysfunction also have many symptoms similar to panic disorder.

Evaluation

There are no specific laboratory, radiographic, or other tests required to diagnose panic disorder. The DSM 5 criteria can be used to diagnose panic disorder which has been mentioned earlier. Certain rating scales designed by clinicians are used in practice to assess the severity of panic attacks.  It is, however, important that healthcare providers perform a thorough examination of the patient to rule out an alternative diagnosis. Panic disorder occurs in the absence of other medical or psychiatric conditions that can better explain the symptoms.[11]

Treatment / Management

The main approaches to the treatment of panic disorder include both psychological and pharmacological interventions. Psychological interventions consist of cognitive-behavioral therapy. As an added benefit in patients with a panic disorder that also has concomitant comorbid medical conditions, there are components of their therapeutic regimens that may also secondarily improve their respective medical illnesses. Breathing training is a method of reducing panic symptomatology by utilizing capnometry biofeedback to decrease the number of episodes of hyperventilation. Several of these slow breathing techniques have been shown to benefit patients with asthma and hypertension. Hyperventilation reduction can help patients with cardiovascular disease. Anxiety and stress-reduction techniques can lower adverse outcomes in cardiovascular illness by decreasing sympathetic activity.   

Antidepressants and benzodiazepines are the mainstays of pharmacologic treatment. Among the different classes of antidepressants, selective serotonin reuptake inhibitors (SSRIs) are recommended over monoamine oxidase inhibitors and tricyclic antidepressants. SSRIs are considered the first-line treatment option for patients with panic disorder. In patients with co-existing conditions or where the patients are having severe symptoms, it is preferred that a benzodiazepine such as alprazolam is used until the anti-depressants take effect. In patients with substance use disorder and panic disorder, it is recommended that gabapentin and mirtazapine be used.[12][13][14]

Because of the risk of suicide, some patients may need inpatient monitoring until the symptoms have subsided.

Differential Diagnosis

• Angina
• Asthma
• Congestive heart failure
• Mitral valve prolapse
• Pulmonary embolism
• Substance use diosrder
• Other mental health disorders associated with panic attacks

Prognosis

Prognosis can be guarded. The presence of panic disorder without other psychopathology is rare. Most people will have a recurrence of symptoms even after a symptom-free period. Compliance with treatment is a major issue, and thus relapse of symptoms is common. Only about 60% of patients achieve remission within 6 months. Triggers for poor outcomes include a chronic illness, high interpersonal sensitivity, unmarried, low social class, and living alone. Besides premature adverse cardiac events, these patients are also at risk for suicide.

Complications

Panic disorder is associated with a higher risk of suicidal ideation. It is also associated with a decrease in the quality of life as the patient is not able to function normally in his social and family life. The disorder is associated with an increased risk of comorbid medical conditions and smoking.