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"The beginnings of diseases and other distempers which are about to visit the body… must be more evident in the sleeping state." —Aristotle, cited in Van de Castle, 1994
"There are nerves coming to the brain from every part of the body—and they relay the signals of impending illness that the subconscious translates into dreams." —Kasatkin, 1967, cited in Van de Castle, 1994
That changes in dream content could reliably predict oncoming physical illness is somewhat controversial, though research supporting the role of somatic and sensory influences on dream content is well supported (discussed in a previous post here).
The idea seems less radical if we first acknowledge that detectable changes occur in the body at the onset of disease, prior to the presence of recognizable symptoms. This is a fact taken for granted in many areas of diagnostic medicine—such as using a blood test to detect early physiological signs of infection or disease. These subtle physiological changes are also detected by the brain on a subconscious level, and may be translated into “prodromal” dreams—dreams that reflect the onset of an illness prior to the appearance of symptoms. Recognizing prodromal dream cues can be particularly useful for establishing early interventions against sickness.
To illustrate, we can use the example of an oncoming cold: As soon as the immune system recognizes the virus, physiological changes begin to take place, such as inflammation of the throat, though it may take some time for these changes to become physically noticeable. In the early onset of the virus, and prior to any physical symptoms, you could have a nightmare of choking and awake distressed; this is a prodromal dream. The dream includes directly relevant imagery of the body's reaction to a virus, i.e., choking due to an inflamed throat. Such a dream, if heeded, could afford you extra time to take defensive measures to shorten the duration of a cold, perhaps by drinking herbal infusions or following other tips.
There are several cases cited in the literature of dreams that directly indicated illness through imagery. For example, dreams preceding migraines have been reported to include pertinent images, such as being shot or struck by lightning in the head (Warnes & Finkelstein, 1971; Gutheil, 1958). Another example:
"A man [who] experienced a recurring dream in which a rat was gnawing at the lower part of his abdomen… was soon diagnosed with a duodenal ulcer." —Mitchell, 1923
This is the most obvious way that dreams can reveal warning signs of illness—through repeated imagery of body wounds or pain. More generally, some common dream features associated with physical illness include an increase in dream recall, and increased distressful and fearful, often violent nightmares, which may persist throughout the night, and over multiple consecutive nights (Kasatkin, cited in Van de Castle, 1994). This is distinct from normal nightmares which tend to occur in isolation in the latter half of a sleep episode (DSM-5).
So watch out for lengthy and distressful dreams that seem to drag on and disrupt sleep all through the night.
Besides emotion, increased bizarreness in dreams is thought to reflect the fatigue associated with sickness. As our body fights disease, we rely on more deep sleep for immune strength, and the delay in dreaming sleep could lead to vivid and bizarre dreams (McNamara, quoted in Kaur, 2013).
Another possibility is that prodromal dreams will incorporate a memory from the past from a time when you were also ill:
"One man who had suffered from severe inflammation of the eyes while in Egypt, suddenly began, 10 years later, to dream regularly of scenes from Egypt. He could not explain these Egyptian dreams, but soon after their appearance he again developed inflammation of his eyes." —Manaceine, 1897, cited in Van de Castle, 1994
In this case, the man's memories of Egypt were triggered by their association to eye inflammation. Thus, it is helpful to be aware of the memory sources of dreams, and take notice of any unexpected memories.
Prodromal dreams have also been studied in relation to more serious illnesses, including cancer and neurodegenerative disorders. There is some anecdotal evidence that prodromal dreams can indicate the location of cancer. For example:
"A breast cancer patient dreamed that her head was shaved with the word 'cancer' written on it. Three weeks later, she received the diagnosis that the cancer spread to her brain." —Siegel, 1983, cited in Van de Castle, 1994
In neurological research, violent and aggressive dreams combined with physically acting out dreams (termed REM behavior bisorder) is an early warning sign of neurodegenerative diseases such as Alzheimer's and Parkinson’s, and can sometimes appear up to 10 years before other symptoms, such as memory loss (Postuma, 2014). Therefore, studying and understanding prodromal dreams could improve prediction of, and preventative measures for, a range of illnesses.
In sum, changes in the body at a subconscious level can correspond with sudden shifts in dream content. In particular, dreams of unexpected memories, repeated physical injury, or lengthy dreams with bizarre or violent imagery could indicate impending illness. Paying attention to these unusual dream experiences could enable you to prepare the first defense against an oncoming illness.
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