What is a Nocturnal Panic Attack?

Panic attacks are a sudden onset of intense anxiety, with physical symptoms such as a rapid heart rate, rapid breathing (hyperventilation), sweating, lightheadedness and shaking (convulsions). Someone experiencing a nocturnal panic attack will wake up suddenly, feeling intense panic, followed by physical symptoms mentioned previously. They usually occur in the first half of the night, during the transition from light to deep sleep. Sometimes they can be the result of a bad dream, but most of the time they occur for no clear reason. Nocturnal panic attacks are experienced by 44-71% of people with panic disorder.¹

Diagnosis

Patients may undergo a mental health assessment to differentiate the nocturnal panic attacks from other disorders e.g. seizures, sleep apnea and anxiety. The diagnosis process generally includes an interview to assess sleep history and current functioning.¹ Sometimes sleep studies will be conducted, for example, an EEG (electroencephalogram) may be carried out while the patient is sleeping. In an EEG, sensors are placed on the patient’s head which detect electrical signals in different regions of the brain, to show which areas are active during certain activities.²

Pharmacological Treatments for Nocturnal Panic Attacks

Common treatments for panic attacks and anxiety include benzodiazepines (BZs), antidepressants or beta-blockers. Although research into treatment for nocturnal panic attacks specifically is limited, studies that have been carried out have shown that these drugs are also effective in nocturnal panic patients. Nocturnal panic attacks are often treated by treatment of an underlying anxiety or panic disorder.

Benzodiazepines

Benzodiazepines (BZs) are the most commonly prescribed treatment for panic disorders. They increase the concentration of a chemical messenger, or neurotransmitter called GABA (gamma-aminobutyric acid), which is responsible for inducing a calming effect by controlling nerve cell hyperactivity. BZs bind to GABA receptors which increases the efficiency of GABA i.e. less is needed to have an effect.

One issue with benzodiazepines is that they are highly addictive; patients are likely to experience withdrawal symptoms even after short-term use. Withdrawal symptoms can be similar to the symptoms the BZs were initially prescribed to treat, such as panic attacks.³

Antidepressants

As the name suggests, antidepressants are mostly used in the treatment of depression. However, they are also used in the treatment of other disorders such as obsessive-compulsive disorder (OCD), panic disorder and generalised anxiety disorder (GAD). The types of antidepressants used to treat panic disorder and nocturnal panic attacks include selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants.⁴

Selective Serotonin Reuptake Inhibitors (SSRIs)

SSRIs such as fluoxetine and sertraline are the most commonly prescribed treatment for depression but are also approved as treatment for generalised anxiety disorder and panic disorder.⁵

The process by which messages are passed through the brain is called synaptic transmission. It involves two neurons; the first is the presynaptic neuron, which releases chemical messengers called neurotransmitters. These neurotransmitters diffuse between a gap called a synapse until they reach the second neuron; the postsynaptic neuron. This neuron has receptors on its surface which neurotransmitters bind to, stimulating the neuron and bringing about an effect. Following transmission, the neurotransmitters are usually reabsorbed by the presynaptic neuron.⁶

Serotonin is a neurotransmitter which is associated with many functions, most notably mood, but it also plays roles in learning, memory, sleep and hunger. A lack of serotonin can lead to problems such as depression, anxiety and sleep problems.

SSRIs inhibit the transporter molecule, serotonin transporter (SERT), which is responsible for serotonin reuptake by the presynaptic neuron. By inhibiting SERT, serotonin remains in the synapse and can continue stimulating receptors on the postsynaptic neuron, allowing its effects to last for longer.⁵

Some of the most common side effects of long-term SSRI use are: gastrointestinal (GI) complications, sexual dysfunction, weight gain and sleep disturbance.⁷

Tricyclic Antidepressants (TCAs)

Tricyclic antidepressants are usually used as a treatment for major depressive disorder (MDD). However, they are also sometimes used in the treatment of anxiety and panic disorders. Similar to SSRIs, they inhibit the reuptake of serotonin, as well as noradrenaline (sometimes referred to as norepinephrine). Noradrenaline is a neurotransmitter whose main function is to contract blood vessels (vasoconstriction), to increase blood pressure.

Due to their vasoconstrictive effects, the use of TCAs may lead to heart complications such as arrhythmias, ventricular fibrillation and cardiac arrest, therefore the patient’s cardiac health must be assessed before prescribing TCAs.⁸

Beta-Blockers

Beta-blockers are often used to treat cardiovascular diseases such as hypertension (high blood pressure), arrhythmias and coronary artery disease. Propranolol is the most common beta-blocker used to treat anxiety. They bind to beta receptors to prevent neurotransmitters from binding to them. When adrenaline and noradrenaline bind to beta-1 and 2 receptors, heart rate and blood pressure increase, therefore, beta-blockers bind to beta-1 and 2 receptors so that they can’t be stimulated by adrenaline and noradrenaline, decreasing heart rate and blood pressure. Propranolol is a non-selective beta receptor inhibitor, meaning that it binds to both beta-1 and 2 receptors with no preference.

Side effects associated with beta-blockers include bradycardia (low heart rate), hypotension (low blood pressure), fatigue, dizziness, nausea and constipation.⁹

Summary

A nocturnal panic attack occurs when the patient wakes up suddenly and experiences an intense wave of anxiety, accompanied by physical symptoms such as elevated heart rate and hyperventilation. Those who experience nocturnal panic attacks usually have an underlying panic or anxiety disorder. Nocturnal panic attacks can be treated with benzodiazepines, antidepressants such as selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs) and beta-blockers.