Sleepwalking is a sleep disorder effecting an estimated 10 percent of all humans at least once in their lives (1) . 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) (3) . 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 (3) . 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 (3) . Others claim that 18% of the population is "prone to sleepwalking" (9) . 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 (9) . 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 (9)  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" (6) .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" (9) . 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 (3) .
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 (5) . 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 (3) . 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 (3) . Stress and alcohol abuse, among other things, have been shown to contribute to sleepwalking among adults (3) . 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 (3) . 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 (2) . Treatments for adult sleepwalkers often includes psychological treatment as well as relaxation techniques and sometimes requires anti-depressants to regulate the behavior (7) . 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.
WWW Sources1)"Is Sleepwalking Normal for Children?" 
2) "Sleepwalking Question."  by Carol King.
3)"Night Flying-An Overview of the Parasomnias."  By Mark Mahowald and Carlos H. Schenck.
4) "The Sleep Disorders of Sleepwalking and Sleep Talking."  By Jennifer Meuller.
5)"Paroxysmal Disorders." 
8)"Sleepwalking Disorder." 
I am interested in sleep walking. I did it as a child and have started doing it again. I am 51 years old and find myself in many different places in my home. I often wake up and when I figure out where I am I go back to the bed room and stay there for the rest of the night
I am 28 years old. I have been sleepwalking for 10 years. I am aware of the situation when i sleepwalk. I just think the situation is real. I have gone looking for people that werent there. I have thought there were bugs everywhere. I have thought there was an earthquake. I will take my alarm clock off the table and put it under it. It makes sense to me as I am doing it. My husband will wake up and tell me that I'm dreaming and I get mad at him and tell him that it is real this time. I'm just wondering if that is normal with sleepwalkers---to remember all that you did. And is there anyway to stop sleepwalking.
I have just got recently engaged to a wonderful man.We live together. He is so great to me, however, he has sleptwalked, talked and even fought ME in his sleep.(because I am right next to him) I was awakened in my sleep to him trying to gouge out one of my eyes,he has gotten up in his sleep and turned on the microwave in the kitchen, sat up and talked to me in his sleep, and so on. I am starting to get worried. It is getting to the point that I have to sleep in the daytime while he is at work, if I want to sleep. I read your posting on this site after having looked up sleepwalking in the search engine. Any insights you may have on this would be extremely grateful.
Additional comments made prior to 2007
yea so last night i think i was sleep walking. im only 15 years old turning 16 in like two weeks.but last night i came home i little drunk and was really really tired. i layed down and i just kept thinking about getting up and brushing my teeth and washing my face. i fell asleep and this morning i woke up with toothpaste in my hair and on my fingers and on my arm and leg. the only person that couldve done that to me would be my parents and im pretty posative it wasnt them but the bathroom was spotless when i woke up. so it lead me to believe i was sleep walking and tryed to brush my teeth ... James, 13 March 2006
Hi, my name's Joe and I have just turned 14. I am a really bad sleepwalker, I recently while asleep ran out of my room to the front door, ran outside and tried to jump over the neighbours fence, I know this because my Mum was watching TV and saw the whole thing. This is one of the worse sleepwalks I have ever done and I also sleeptalk alot and many other stuff. I am quite scared that one day I might wake up somewhere I have never been or even worse not wake up at all. And I would like to know if there are any things that can help prevent sleepwalking. Thank you for your time ... Joseph Agius, 24 March 2006
Hi I don't have a comment but a Question, a freind and I were talking the other day about sleep walking and the subject of not being able to wake a person up that is sleep walking because he said a freind of his had driven a car. I asked why they didn't wake him and he said you are not suppose to wake a sleep walker. My question is is that true and if it is true why is that? ... Les Redding, 8 October 2006
Hi i am only 11 years of age. I sleep walk probably almost every other night. When i wake up i have no clue what has happened.This morning my mom told me i had slepwalked. That night i went downstairs asked my mom what she was doing(of course i was sleepwalking) she told me she was going to go to sleep,then she asked me what i was doing then i said i was just going to watch T.V.She told me it was 11 o clock and i needed to go to sleep so i yelled "FINE" then went back upstairs. Later at 6:30 when my mom usually wakes me for school she called me then i yelled "morning!" then fell asleep. she noticed i wasnt down a little while later so she called.This time i woke up and went on with my day......Is that normal for a child my age to sleep walk? ... Ruby, 21 November 2006
I have a son age six who has been sleepwalking and talking scince he could walk and talk,he tries to get out of the windows, doors, and often throws his toys or what ever is in his way across the room cursing at what ever he is dreaming of, this is taking it toal on our family as he does not go one night without waking more than three times a night, he is a very emotional person easily frustrated etc. we are currently waitng on a hospital opt so he can be assesed but in the mean time do you have any advice? ... Leanne Fox, 11 October 2007
I am alarmed that you say those who begin sleepwalking later in life tend to keep it up. I am 67, and last night fell out of bed on my head. I hurt my arm and have a knot on my head. It hurt like the dickens. This is one of many episodes that I have had in the past 3 or 4 years. I have awakened my husband, telling him the ceiling is on fire, I have crawled over the footboard to "escape", tried to get out of the front door, etc. I am afraid I have some form of strokes. My doctor wants me to go to a sleep clinic. Any opinion? ... Martha Meyer, 18 october 2007
I'm interested in the subject of sleepwalking because i feel this is influencial in the beginning stages of life as a person. As a fact, we understand they grow out if it. Like if flowing in natural, somewho a stage or natural behavior into growing up. I'm trying to write a childrens book and so i want to be familiar to their way of thinking of learning. Habits that mark their life through adulthood and influence them to the their way of way of think and viewing perspectives. How are paradigms created? ... Juan Adame, 27 October 2007