Sleepwalking is a sleep disorder effecting an estimated 10 percent of all humans at least once in their lives.
This widespread phenomenon varies in its intensity and frequency. While most sleepwalking incidents are short and not dangerous, some can involve self-injury and are much more dangerous for the sleeper. Also, most interestingly, the disorder seems to stem from many different sources, not from one definable cause such as a chemical imbalance. While it is predominantly pre-adolescents who suffer from somnambulism, it is also observed in adults, although the frequency and severity of incidents increase with age. The source of the disorder was once thought to be entirely psychological and an extension of dreaming. It is now understood to be a complex combination of one or more factors, such as psychological and physiological factors as well as chemical interference (such as alcohol and drug abuse). The source of the sleepwalking behavior varies according to age with the younger sufferers having more physiological problems which they grow out of, while older somnambulists, stress and substance abuse play a larger role.
Somnambulism is most common among children from the ages of 4 to 12 . Estimates for the percentage of the population which will sleepwalk at least once in their lifetime range quite a bit. Some sources say that most children will walk in their sleep at least once, with 15% sleepwalking more regularly . Others claim that 18% of the population is "prone to sleepwalking" . There is consensus, however, on the fact that boys sleepwalk more frequently than girls and that it is between the ages of 11 and 12 that the most cases of sleepwalking are reported. The fact that most children grow out of it after puberty and that people who start sleepwalking later in life tend to have the problem for the rest of their lives seems to suggest that there are at least two classes of somnambulism, which may stem from different sources.
Sleepwalking most often occurs at a certain point in the sleep "architecture" .This is the point where the sleeper's brain waves have become larger and he or she has moved into deeper sleep. This is not REM sleep, but deep non-REM sleep. The series of complex behaviors characterizing somnambulism includes "amnesia following an episode," and "difficulty in arousing the patient during an episode" . The patient can also have other REM disorders or psychiatric and medical disorders which do not account for the sleepwalking. While sleepwalking, the patients' brainwaves show a mixture of types of brainwave patterns, including ones similar to those observed in waking patients, as well as those found in deep sleep. It is the "awake" patterns which match the waking behaviors like walking and talking while the patient is still asleep enough so that he or she is not aware of what it happening and is not forming memories of their actions.
The difference between older people's sleepwalking and that of children may be related to the sleep pattern changes a person undergoes as he grows older. Children spend more time in deep sleep (the stage during which sleepwalking is initiated) and as one becomes older, sleep is more fragmented, with more time spent in light sleep. The physiological aspects of sleepwalking probably have more to do with the cause of sleepwalking in children because they spend more time in deep sleep. To support the idea that it is physiological sources that cause the disturbance in their sleep, children undergo physiological changes (puberty) which cause the symptoms to go away without the intervention of drugs or other treatment. This is observable in the significant drop in post-pubescent incidences of sleepwalking. Drug therapies are also effective in stopping the problem for many children, implying that it is a chemical cause for the disorder in many cases involving young patients . There is also a genetic tendency for sleepwalking in adolescence which some people inherit and which plays out so that children in a family will often all sleepwalk, or uncles and parents will have sleepwalked in their childhood and outgrown it . This is another indication that childhood sleepwalking has less to do with psychological and substance abuse factors than with purely physiological factors.
On the other hand, if a patient begins sleepwalking later in life, he is more likely to have the disorder for the rest of his life . Stress and alcohol abuse, among other things, have been shown to contribute to sleepwalking among adults . Fatigue also increases the chances of a person sleepwalking because it forces the body to go into deeper sleep, allowing the dysfunctional transition into deep sleep to occur more readily, leading to somnambulism. Far fewer adults sleepwalk than do children, only about only about 1 in 200 . Adult sleepwalking is more serious in that it is often more aggressive, and so has more potential for self-injury. Sleepwalkers are not allowed in the armed services of the United States, at least partly because of the threat they pose to themselves and others when they have access to dangerous equipment (such as weapons) and are unaware of what they are doing when they sleep. Treatments for adult sleepwalkers often includes psychological treatment as well as relaxation techniques and sometimes requires anti-depressants to regulate the behavior . The difference in effective treatment from children to adult implies a different source for the disturbance. A more psychological or substance abuse-related set of causes seem to exist for adults.
Sleepwalking is a serious disorder for some and a mild annoyance for others. However, no matter whether it happens infrequently or often, there is the potential for harm to the person who is walking around without having full use of his brain's decision-making capabilities. The more common "type" of somnambulism, that affecting children, is less intrusive and goes away faster than the kind associated more with adults. This could be because the source is natural and a part of growing up and perhaps a part of the changing nature of the sleep patterns occurring during adolescence. Children grow out of their sleepwalking, but adults who suffer from it have in a way inflicted it on themselves or been influenced by the outside world. They then have to treat this other problem, such as a psychological problem, stress, or a drug habit, in order to get rid of the symptoms.
