Explanations of Sleep DisordersPSYCHOLOGY – PY4

Definition of a Sleep Disorder

A sleep disorder is any condition that involves difficulty experienced when sleeping. Such disorders involve daytime fatigue causing severe distress and impairment to work. Sleep disorders can also have an impact upon social and personal functioning. Sleep disorders can be classified as;Having problems falling or staying asleep (insomnia)Problems staying awake, such as RLS, sleep apnoea and narcolepsyProblems adhering to regular sleep schedules due to jet travel of shift workSleep disruptive behaviours referred to as parasomnias. Behaviours occurring around sleep such as sleep walking and night terrors.

InsomniaInsomnia is a condition that most of us experience sometime during our lives. Insomnia is either the inability to fall asleep, an inability to stay asleep or both. Symptoms; tiredness, fatigue, inability to concentrate, irritability etc. According to Dement insomnia should not be classed as a sleep disorder in its own right but a symptom of other disorders which at times may be unknown. Primary insomnia

This has no obvious cause so appears to be an illness of its own right. It is the most common form of insomnia. DSM IV diagnosis the patient must have had problems sleeping for at least a month, the lack of sleep has resulted in social impairment, the insomnia is not the result of any other sleep disorder etc.Secondary insomnia

This is where the inability to sleep is a result of other sleep disorders such as RLS, depression or anxiety etc. other cause may include jet lag or shift work resulting in the desynchronisation of biological rhythms. Also physical injuries resulting in pain or certain drugs such as codeine and various recreational drugs.

Dauvillers et al (2006)This study put insomniacs through a battery of tests, questionnaires and clinical interviews. They found that 73% of insomniacs reported a family history of insomnia compared to only 24% of non-insomniacs. This does not explain the family link. The assumption here is that insomnia may be genetic. According to this research is insomnia genetic?

This research suggests that insomnia doesn’t have a link to genetics because 24% of non-insomniacs have reported a family history of insomnia. The percentage of insomniacs reporting a family history would be higher than the result of 73%Smith et al (2002)In this study evidence was found for psychological differences in the brains of insomniacs. Nine women, 5 insomniacs and 4 controls slept in a sleep lab for 3 nights. They were studied using a polysomnograph and on the third night underwent a brain scan. It was found that the insomniacs had a significantly reduced flow of blood to various areas of the cerebral cortex suggesting abnormal CNS activity during NREM sleep. This research suggests that insomniacs are psychologically different.Three weaknesses of this study is that is lacks population validity, ecological validity and may be bias when selecting participants. E.g. all women, all similar age etc.

Morin et al (2003)This study investigated the link between stress and insomnia. 67 participants comprising 40 insomniacs and 27 controls completed a series of questionnaires assessing;Their daily stressorsTheir pre-sleep levels of arousalThe quality of their sleep Although the insomniacs were experiencing similar numbers of stressful events to the control group they were reporting significantly higher levels of anxiety. They also reported their lives as being more stressful and were more likely to use emotion-focused coping mechanisms.This research does not suggest that insomnia can be caused by stress as the insomniac participants were found to be experiencing similar numbers of stressful events to the control group. A weakness of this study is that it can not be generalisable as the amount of participants are not significant enough to generalise to all insomniacs.

A Case Study in InsomniaMrs. A, aged 42 was referred to a sleep disorders centre with complaints of chronic, severe insomnia where it was affecting her daytime functioning. Mrs. A is a mother of 3 teenage boys and first experienced insomnia 8 years before she was referred when bankruptcy threatened her small business. Although her business recovered, her insomnia has remained with her 8 years on. Medication history showed that she had taken Temazepam, Zolpidem, Zaleplon and many antidepressants such as Trazodone, Amitriptyline and Mirtazapine. All were unsuccessful. Mrs. A gave up on each one after 1-2 weeks because of side effects or lack of efficiency. Social history made her feel like she was just “hanging on by her fingernails” and that taking care of her business and her boys had taken all of her energy whilst suffering with insomnia. Her lack of sleep has forced her to give up on her social life, including her gym workouts. She had begun drinking 4-5 strong mugs of coffee per day to keep herself awake but naps whenever possible.Review of sleeping pattern found that Mrs. A tries to go to bed after her oldest boy is home and settled – typically around 11pm. She falls asleep in less that 15 minutes, but occasionally it takes her hours. She wakes up 3 or 4 times a night, and at least one of these awakenings can last 2-3 hours.Physical examination found Mrs. A to be healthy but suffering from excessive sleepiness, fatigue and lack of energy. A concomitant psychiatric interview revealed high stress but no evidence of depression, anxiety etc.Treatment: She was put in contact with an organisation to help review her business practices. Her caffeine intake was reduced. Mrs. A enrolled in a course of relaxation through meditation and 2 sessions of cognitive therapy were completed to discuss her dysfunctional beliefs about sleep. After 6 months Mrs. A’s sleep improved and she only slept poorly for 2 nights a week. After a year she felt like her life was much improved with everything running smoother. A 5 year follow up showed that Mrs. A slept fine with no hypnotics.

Parasomnia A disorder characterized by abnormal or unusual behaviour of the nervous system during sleep

Confusional arousals – usually occur when a person is awakened from a deep sleep during the first part of the night. This disorder, which is also known as excessive sleep inertia or sleep drunkenness, involves an exaggerated slowness upon awakening.Rhythmic movement disorders – occurs mostly in children who are one year old or younger. A child may lie flat, lift the head or upper body and then forcefully hit his or her head on the pillow.Nightmares – are vivid nocturnal events that can cause feelings of fear, terror, and/or anxiety. Usually, the person having the nightmare is abruptly awakened from REM sleep and is able to describe detailed dream content. Sleepwalking – occurs when a person appears to be awake and moving around but is actually asleep. Sleepwalkers have no memory of their actions. Sleepwalking most often occurs during deep non-REM sleep early in the night.

Sleepwalking Sleepwalking is more common in children than adults. Hublin et al suggests 20% of children are affected by sleepwalking where as it is said to affect only 3% of adults.The neurotransmitter GABBA is the primary inhibitory neurotransmitter, which means it decreases the neurons action potential. It is released when we are entering sleep stages. Oliverio suggests that the GABBA system is not fully developed in children; it may also be underdeveloped in some adults. It was found that certain deficits in the neural circuits of some adults when compared to controls. Broughton (1968)Found that the prevalence of sleepwalking in first degree relatives of an affected individual is at least 10x greater than that in the general population. This suggests that there may be a genetic link to sleepwalking however this doesn’t say that this behaviour isn’t genetic and it could be learnt. Lecendreux (2003)Found a 50% concordance rate in MZ twins compared to a 10-15% concordance rate in DZ twins. Lecendreux identified the DQB1*5 gene. This suggests that there is a genetic link and contradicts Broughton.

Narcolepsy Narcolepsy usually begins in adolescence or early adulthood, and continues through the persons life. It is thought that 1 in 2000 people suffer from this disorder but cannot be accurate as not everybody who has the symptoms goes to the doctors about it. In the 1960s it was considered that it occurred as a result of a malfunction in the systems which maintain REM sleep.Vogel (1960)Found that REM sleep occurred at the onset of sleep in narcoleptics. This explained some of the symptoms of the disorder such as the loss of muscle tone and hallucinations. In the 1980s research suggested that it was linked to a mutation of the immune systemHonda et al (1983) Found an increased frequency of one type of human leukocyte antigen (HLA) in patients. HLA molecules coordinate the immune response and are found on the surface of white blood cells.In the 1990s, research has shown a link between low levels of hypocretin and the disorder. Hypocretin is thought to play a role in maintaining wakefulnessLin et al Found narcoleptic dogs had a mutation in a gene on chromosome 12 which disrupted the way that hypocretin was processed. Nishino et al (2000)Found that humans had low levels of hypocretin in their CSFMignot (1998) AO2Found that there was no significant increased risk of one twin developing narcolepsy if the other twin had it.