Panic disorder in the context of "Dual diagnosis"

Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of its distinct sensations, the degree of distress and discomfort involved, and its burden or impact on the patient's activities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen). The tripod position is often assumed to be a sign.

Dyspnea is a normal symptom of heavy physical exertion but becomes pathological if it occurs in unexpected situations, when resting or during light exertion. In 85% of cases it is due to asthma, pneumonia, reflux/LPR, cardiac ischemia, COVID-19, interstitial lung disease, congestive heart failure, chronic obstructive pulmonary disease, or psychogenic causes, such as panic disorder and anxiety (see Psychogenic disease and Psychogenic pain). The best treatment to relieve or even remove shortness of breath typically depends on the underlying cause.

Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, insomnia, and seizures. The first benzodiazepine, chlordiazepoxide (Librium), was discovered accidentally by Leo Sternbach in 1955, and was made available in 1960 by Hoffmann–La Roche, which followed with the development of diazepam (Valium) three years later, in 1963. By 1977, benzodiazepines were the most prescribed medications globally; the introduction of selective serotonin reuptake inhibitors (SSRIs), among other factors, decreased rates of prescription, but they remain frequently used worldwide.

Benzodiazepines are depressants that enhance the effect of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA_A receptor, resulting in sedative, hypnotic (sleep-inducing), anxiolytic (anti-anxiety), anticonvulsant, and muscle relaxant properties. High doses of many shorter-acting benzodiazepines may also cause anterograde amnesia and dissociation. These properties make benzodiazepines useful in treating anxiety, panic disorder, insomnia, agitation, seizures, muscle spasms, alcohol withdrawal and as a premedication for medical or dental procedures. Benzodiazepines are categorized as short-, intermediate-, and long-acting. Short- and intermediate-acting benzodiazepines are preferred for the treatment of insomnia; longer-acting benzodiazepines are recommended for the treatment of anxiety.

Interoception is the collection of senses providing information to the organism about the internal state of the body. This can be both conscious and subconscious. It encompasses the brain's process of integrating signals relayed from the body into specific subregions—like the brainstem, thalamus, insula, somatosensory, and anterior cingulate cortex—allowing for a complex and highly accurate representation of the physiological state of the body. This is important for maintaining homeostatic conditions in the body and, potentially, facilitating self-awareness.

Interoceptive signals are projected to the brain via a diversity of neural pathways, in particular from the lamina I of the spinal cord along the spinothalamic pathway and through the projections of the solitary nucleus, that allow for the sensory processing and prediction of internal bodily states. Misrepresentations of internal states, or a disconnect between the body's signals and the brain's interpretation and prediction of those signals, have been suggested to underlie conditions such as anxiety, depression, panic disorder, anorexia nervosa, bulimia nervosa, posttraumatic stress disorder (PTSD), obsessive compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), alexithymia, somatic symptom disorder, and illness anxiety disorder.

Hyperventilation is irregular breathing that occurs when the rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce. This leads to hypocapnia, a reduced concentration of carbon dioxide dissolved in the blood. The body normally attempts to compensate for this homeostatically, but if this fails or is overridden, the blood pH will rise, leading to respiratory alkalosis. This increases the affinity of oxygen to hemoglobin and makes it harder for oxygen to be released into body tissues from the blood. The symptoms of respiratory alkalosis include dizziness, tingling in the lips, hands, or feet, headache, weakness, fainting, and seizures. In extreme cases, it may cause carpopedal spasms, a flapping and contraction of the hands and feet.

Factors that may induce or sustain hyperventilation include: physiological stress, anxiety or panic disorder, high altitude, head injury, stroke, respiratory disorders such as asthma, pneumonia, or hyperventilation syndrome, cardiovascular problems such as pulmonary embolisms, anemia, an incorrectly calibrated medical respirator, and adverse reactions to certain drugs. Hyperventilation can also be induced intentionally to achieve an altered state of consciousness such as in the choking game, during breathwork, or in an attempt to extend a breath-hold dive.

A sense of impending doom is a medical symptom that consists of an intense feeling that something life-threatening or tragic is about to occur, despite no apparent danger. Causes can be either psychological or physiological. Psychological causes can include an anxiety disorder (e.g., panic disorder), depression, or bipolar disorder. A sense of impending doom often precedes or accompanies a panic attack. Physiological causes could include a pheochromocytoma, heart attack, blood transfusion, anaphylaxis, or use of some psychoactive substances. The feeling can also be a transient side effect of adenosine administration, likely due to its activation of adenosine receptors. Due to adenosine's extremely short half-life, this effect is typically short-lived. A sense of impending doom can also present itself as a postoperative complication encountered after surgery.

Monoamine oxidase inhibitors (MAOIs) are a class of drug that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). MAOIs are effective antidepressants due to their specialized function of the inhibition of the enzyme that is responsible for neurotransmitter degradation in the synaptic cleft. This is especially true for treatment-resistant depression, which is a type of depression that is resistant to common treatments of typical depression, such as selective-serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs).

MAOIs are also utilized to treat panic disorder, social anxiety disorder, Parkinson's disease, and several other disorders.