Dreams and nightmares
Each of us has dreams every night, but we remember only a small proportion of their content. Moreover, researchers can obtain information on the content of dreams only from reports of them, and so it is not particularly reliable. But different reports have so much in common that some of the general characteristics of dreams can be determined. 

Dream and divination down the ages
Historically, the most prevalent view about dreams was that they predict the future. Written records of dream interpretation date back at least 4000 years and are found in the archives of the ancient Egyptians, the Babylonians, the ancient Indians, the Sumerians, the ancient Greeks and Romans, and others. In the Greek and Roman world, many enterprising soothsayers and priests made a profitable business of dream divination, and the Greeks also incorporated a kind of dream therapy into their medical practice.

• When modern science plays its role ...

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Menopause: don’t worry

Dreams and nightmares

Each of us has dreams every night, but we remember only a small proportion of their content. Moreover, researchers can obtain information on the content of dreams only from reports of them, and so it is not particularly reliable. But different reports have so much in common that some of the general characteristics of dreams can be determined. They commonly feature a familiar location or ordinary everyday surroundings, rarely a bizarre or exotic setting. Visual imagery dominates, but most dreams have some auditory features. The majority seem to reflect or relate to, events, emotions and thoughts that have been experienced in the recent past — often within a day or two — and their content can often be recognised as a mixture of past experience, personal interests, wishes, and inclinations. Stimuli currently operating on the body are also important. A full bladder, for instance, will frequently make its tensions known in a dream, and if a man's seminal vesicles are full, he may have an erotic ('wet') dream involving orgasm. For reasons that are not clear, the emotional content of dreams — if there is any emotional content — tends more often to be unpleasant than pleasant, with the commonest emotions experienced being anxiety or fear, followed by anger.

Freud on dreams: To Freud, dreams were the 'royal road' to the unconscious mind, revealing to the psychoanalyst the buried secrets of the inner life. It seemed to him that thinking during sleep was less repressed than conscious thoughts so that the unconscious preoccupation with sex and aggression had freer rein. He suggested that every dream has a manifest content — the remembered details — and a latent content — the repressed infantile, sexual and aggressive wishes of the dreamer. He believed that the dreaming psyche disguises the real nature of the inner life, distorting the details or representing them symbolically. Without this disguise the true nature of the inner life would be so shocking as to wake the dreamer.

Sometimes a number of latent elements were, he claimed, represented by a single manifest element — a process Freud called condensation. Similarly, emotions felt towards one person or object were transferred, in the dream, to another person or object. This he called displacement. Freud also claimed that people unwittingly altered the accounts or recollection of their dreams so as to make more sense of them. This complex of processes, by which the latent content is converted into the manifest content, Freud called the dreamwork. His theories of dreams have had a considerable influence on the practice of psychotherapy, but are not widely used in academic psychology today, as they cannot be empirically tested.

REM sleep and dreams: In the early 1950s, studies of human behaviour during sleep revealed that there are periods during which the eyes move rapidly, and that this is associated with other changes. It is now well known that about an hour after we fall asleep, our voluntary muscles, which have been normally tense, suddenly relax, our eyes move rapidly from side to side under our lids, our breathing deepens, our heart rate becomes irregular, and the electrical pattern of the brain waves, the electroencephalogram or EEG, comes to resemble that of an alert, awake person. In 95% of men, the penis becomes erect.

The whole phenomenon is known as rapid eye movement (REM) sleep, and each period of REM sleep lasts for 5-30 minutes. When wakened from REM sleep, 80-90% of people report that they have been having vivid dreams. The dreaming appears to be continuous during REM sleep, and people commonly report long dreams following extensive periods of uninterrupted REM sleep. These episodes of REM sleep are followed by more quiescent periods of deeper sleep during which the EEG pattern becomes much slower with higher amplitude waves, and the muscles become somewhat more tense. People woken up during this phase of sleep seldom admit to having real dreams but only to having been in a state of calm thoughtfulness. These two phases alternate on a 30 to 90 minute cycle, REM sleep constituting, on average, about 20% of the total sleeping time. The time spent in REM sleep increases towards the end of an undisturbed night.

When attempts are made to deprive people of REM sleep by waking them as soon as the REM stage starts, a remarkable phenomenon can be observed. On each successive night in which this is done there is an increase in the number of times the subjects try to enter REM sleep. To begin with, they may have to be wakened 7 or 8 times. By the fifth night they may have to be wakened 30 times. If they are then left undisturbed they spend a far higher than normal proportion of the time, during the next few consecutive nights, in REM sleep. Deprivation of REM sleep has striking effects during waking hours, causing irritability, anxiety, loss of concentration, suspiciousness, apathy and even a tendency to hallucinations.

In babies and infants REM sleep persists for half the sleep cycle — more than twice as long as in adults. This probably implies that infants dream much more than adults do. Some scientists believe that REM sleep in babies is necessary for the normal growth and functional connection of nerves. Old people, too, sometimes show an increase in the proportion of time spent in REM sleep. REM sleep is not limited to humans; many vertebrates, including all mammals, exhibit the symptoms, and this, taken with other evidence, suggests that many animals have a rich dream life.

The undeniable need for REM sleep does not necessarily imply that it is dreaming that is essential to us. So far, research has not been able to throw light on whether the dreaming is a central part of the phenomenon or merely a kind of byproduct.

Modern theories of dreams: Ideas on the function of dreaming are still entirely speculative. We know that the brain needs constant stimulation to continue to function normally, and one suggestion is that dreaming is a way of helping to maintain brain function during sleep, when the amount of external stimulation is much reduced. Some neurophysiologists reject the notion that dreams have any psychological meaning or importance. In their view, dreams are simply the result of random stimulation of areas of the cerebral cortex that subserve conscious experience. When this happens, an attempt has to be made to make sense of the resulting impressions and these, they say, are our dreams. It has also been suggested that dreams are the result of the brain's actions in trying to erase false associations by disconnecting erroneous neural links between brain cells. This process might serve the essential function of allowing correct memory processing. The bizarre content of dreams, then, is in fact the record of material that is to be purged from the individuals' memory.

On the basis of experimental evidence, other neurophysiologists have concluded that formerly acquired information vital to an animals' survival is accessed during REM sleep and integrated with immediate past experience so as to modify future behaviour and increase the chances of survival. According to this theory, our own dreams may have a similar mechanism and function. It has been suggested that this mechanism may have been inherited from our prehuman ancestors, and that the largely visual content of our dreams reflects the absence of speech in other animals. Supporting evidence has been derived from studies of the reported REM dreams of people suffering from marital problems, where the contents of the dreams are strongly related to the ways in which these people are coping with their real-life crises.

(Courtesy Dr Christine Winters and Dr Stephen Adamsom)

Dream and divination down the ages

Historically, the most prevalent view about dreams was that they predict the future. Written records of dream interpretation date back at least 4000 years and are found in the archives of the ancient Egyptians, the Babylonians, the ancient Indians, the Sumerians, the ancient Greeks and Romans, and others. In the Greek and Roman world, many enterprising soothsayers and priests made a profitable business of dream divination, and the Greeks also incorporated a kind of dream therapy into their medical practice.

The Bible, especially the Old Testament, is rich in dream interpretation and prophecy. The story of Joseph's dream in the 37th chapter of Genesis is a case in point. Joseph merely recounted his dreams about his brothers' sheaves of corn that bowed low to his sheaf, and about the sun, moon and eleven stars that bowed low before him; it was his brothers and father who interpreted them as meaning that Joseph would become king. There are strong implications in this story that dreams of obvious symbolic content were taken to be both prophetic and to reflect the wishes of the dreamer. In spite of the prevalence of belief in magic, there were some who were able to examine the subject more dispassionately. Aristotle (384-322 BC), with remarkably modern insight, pointed out the connection between dreams and previously experienced external events, and recognised the way in which normal sensory data can be distorted by emotional factors. In the Roman period, Marcus Tullius Cicero (106-43 BC), in his book De diviniatione, mounted a scathing attack on the dream superstitions of the age. Six hundred years later, Prophet Mohammed (c. AD 570-632), distressed at the extent to which the lives of the people were being influenced by dream divinations, expressly forbade the practice. These few voices of common sense did not, however, have much effect on the mass of public superstition, and it was not until well into the 19th century that thinking people began to recognise that dreams were more likely to be a reflection of what was going on in the mind than what might later happen outside the body.

When modern science plays its role ...

In rare cases, adults may continue to suffer night terrors in their sleep, a phenomenon usually confined to childhood. These terrors bring on sudden attacks of severe anxiety, racing pulse and respiration, and the person may wake up screaming. During these terrors, sufferers may experience a sense of suffocation, claustrophobia, or even the conviction that they are about to die. Recording the sleeper's eye movements, as shown here, may uncover the cause.

Menopause: don’t worry

I wonder if any reader who knows the Rigveda well and is familiar with Charak Samhita will enlighten us about any reference to this subject in these texts.