Nocturnal Panic Attacks: Waking Up with Fear and a Racing Heart

A nocturnal panic attack seems odd, because in sleep there are no stimuli that could provoke fear. Studies indicate, however, that such episodes occur in non-rapid-eye-movement (NREM) sleep and not in REM sleep, in which vivid dreams occur. That distinguishes them from typical nightmares: the person wakes suddenly in a state of full arousal, often with no memory of the content of a dream, and only then feels fear and bodily symptoms.

What, then, sets off the attack? According to the Craske and Tsao review, people with nocturnal panic do not differ from those without it in sleep architecture, sleep physiology, subjective sleep quality or the severity of panic disorder, so there is no simple ‘signal in sleep’. It is thought that sensitivity to internal bodily cues matters: in deep sleep, small changes in breathing, heart rhythm or muscle tension may be read as a threat by a system that during the day has learned to react with fear to such sensations. This is a theoretical model, and the precise physiological triggers still require research.

Not every waking with fear is a panic attack. The Craske and Tsao review stresses that nocturnal panic is a NREM phenomenon distinct from sleep terrors, sleep apnoea, nightmares and dream-induced arousals, and that assessment focuses precisely on ruling out these other explanations, using history, polysomnography and ambulatory recording.

Particular attention has been paid to the link with sleep apnoea. A survey of 301 sleep apnoea patients showed that obstructive sleep apnoea can cause symptoms resembling a nocturnal panic attack, which is why the authors recommend including it in the differential diagnosis. If someone snores, wakes choking, has morning headaches and daytime sleepiness, and night-time attacks occur without panic attacks by day, a sleep study is worth considering (see our knowledge-base entry on sleep apnoea).

Nocturnal panic is predisposed above all by panic disorder, and it can be worsened by factors that stimulate the nervous system or disturb sleep: chronic stress, sleep deficit, caffeine in the afternoon and evening, alcohol (after initial calming it worsens sleep structure and can cause night-time awakenings with palpitations), nicotine, some drugs and the sudden stopping of sedative drugs. These are clinical observations and general knowledge of sleep physiology, not the result of a single study on nocturnal panic.

There are no separate large clinical trials for nocturnal panic, so we rely on evidence for panic disorder, of which it is a symptom. The Craske and Tsao review indicates that cognitive behavioural therapy (CBT) targets misinterpretations of anxiety sensations, the hyperventilatory response and conditioned associations with signals from the body, and that more recent data support its efficacy in nocturnal panic too. The review’s authors found no controlled studies of drugs in people with nocturnal panic.

How does this translate into practice? Effective treatment of panic disorder by day should also reduce night-time attacks, but we have no separate evidence for each method. In CBT one learns to recognize catastrophic interpretations (for example ‘I wake with a pounding heart, so it is a heart attack’), to gradually get used to bodily sensations and to avoid behaviours that maintain fear, such as constantly checking the pulse or avoiding sleep. The choice of further treatment, including any medication, rests with the doctor; do not stop or change drugs on your own.

Relaxation techniques and mindfulness can be helpful as a supplement, but they do not replace therapy for panic disorder. We do not recommend supplements ‘for nocturnal panic’ — such studies are lacking, and some can interact with drugs (we write about interactions separately).

The Craske and Tsao review notes that assessing nocturnal panic consists mainly of ruling out other explanations. The doctor usually asks about daytime symptoms, snoring, drugs and substances and, depending on the picture, may order basic tests.

What we do not cover: sleep terrors and behaviour disorders in sleep, which require a separate assessment, or details of drug treatment of panic disorder. We also do not describe nocturnal epileptic seizures, which can wake a person from sleep and need neurological assessment.

For someone who wakes with a feeling of impending death, the hardest thing is that the attack seems to be proof of a serious illness. Reliable knowledge changes that perception: it is a known phenomenon that can be understood, diagnosed and treated, and the diagnosis should always include an honest exclusion of organic causes, including apnoea and heart rhythm disturbances.