and a growing resemblance between some sleep stages (n1 and n2). more than 65% of people with alzheimer's disease have this type of sleep disturbance. one factor that could explain this change in sleep architecture is a change in circadian rhythm, which regulates sleep. a disruption of the circadian rhythm would generate sleep disturbances. some studies show that people with ad have a delayed circadian rhythm, whereas in normal aging, an advanced circadian rhythm is present. in addition to these psychological symptoms, at a neurological level there are two main symptoms of alzheimer's disease. the first is an accumulation of beta-amyloid waste forming aggregate "plaques". the second is an accumulation of tau protein. it has been shown that the sleep-wake cycle acts on the beta-amyloid burden, which is a central component found in ad. as individuals awaken, the production of beta-amyloid protein will be more consistent than its production during sleep. this is explained by two phenomena. the first is that the metabolic activity will be higher during waking, thus resulting in greater secretion of beta-amyloid protein. the second is that oxidative stress will also increase, which leads to greater ab production. on the other hand, it is during sleep that beta-amyloid residues are degraded to prevent plaque formation. the glymphatic system is responsible for this through the phenomenon of glymphatic clearance. thus, during wakefulness, the ab burden is greater because the metabolic activity and oxidative stress are higher, and there is no protein degradation by the glymphatic clearance. during sleep, the burden is reduced as there is less metabolic activity and oxidative stress (in addition to the glymphatic clearance that occurs). glymphatic clearance occurs during the nrem sws sleep. this sleep stage decreases in normal aging, resulting in less glymphatic clearance and increased ab burden that will form ab plaques. therefore, sleep disturbances in individuals with ad will amplify this phenomenon. the decrease in the quantity and quality of the nrem sws, as well as the disturbances of sleep will therefore increase the ab plaques. this initially occurs in the hippocampus, which is a brain structure integral in long-term memory formation. hippocampus cell death occurs, which contributes to diminished memory performance and cognitive decline found in ad. although the causal relationship is unclear, the development of ad correlates with the development of prominent sleep disorders. in the same way, sleep disorders exacerbate disease progression, forming a positive feedback relationship. as a result, sleep disturbances are no longer only a symptom of ad; the relationship between sleep disturbances and ad is bidirectional. at the same time, it has been shown that memory consolidation in long-term memory (which depends on the hippocampus) occurs during nrem sleep. this indicates that a decrease in the nrem sleep will result in less consolidation, resulting in poorer memory performances in hippocampal-dependent long-term memory. this drop in performance is one of the central symptoms of ad. recent studies have also linked sleep disturbances, neurogenesis and ad. the subgranular zone and the subventricular zone continued to produce new neurons in adult brains. these new cells are then incorporated into neuronal circuits and the subragranular zone, which is found in the hippocampus. these new cells contribute to learning and memory, playing an essential role in hippocampal-dependent memory. however, recent studies have shown that several factors can interrupt neurogenesis, including stress and prolonged sleep deprivation (more than one day). the sleep disturbances encountered in ad could therefore suppress neurogenesis—and thus impair hippocampal functions. this would contribute to diminished memory performances and the progression of ad, and the progression of ad would aggravate sleep disturbances. changes in sleep architecture found in patients with ad occur during the preclinical phase of ad. these changes could be used to detect those most at risk of developing ad. however, this is still only theoretical. while the exact mechanisms and the causal relationship between sleep disturbances and ad remains unclear, these findings already provide a better understanding and offer possibilities to improve targeting of at-risk populations—and the implementation of treatments to curb the cognitive decline of ad patients. sleep disorder symptoms in psychiatric illnesses schizophrenia in individuals with psychiatric illnesses sleep disorders may include a variety of clinical symptoms, including but not limited to: excessive daytime sleepiness, difficulty falling asleep, difficulty staying asleep, nightmares, sleep talking, sleepwalking, and poor sleep quality. sleep disturbances - insomnia, hypersomnia and delayed sleep-phase disorder - are quite prevalent in severe mental illnesses such as psychotic disorders. in those with schizophrenia, sleep disorders contribute to cognitive deficits in learning and memory. sleep disturbances often occur before the onset of psychosis. sleep deprivation can also produce hallucinations, delusions and depression. a 2019 study investigated the three above-mentioned sleep disturbances in schizophrenia-spectrum (scz) and bipolar (bp) disorders in 617 scz individuals, 440 bp individuals, and 173 healthy controls (hc). sleep disturbances were identified using the inventory for depressive symptoms - clinician rated scale (ids-c). results suggested that at least one type of sleep disturbance was reported in 78% of the scz population, in 69% individuals with bd, and in 39% of healthy controls. the scz group reported the most number of sleep disturbances compared to the bd and hc groups; specifically, hypersomnia was more frequent among individuals with scz, and delayed sleep phase disorder was three times more common in the scz group compared to the bd group. insomnias were the most frequently reported sleep disturbance across all three groups. bipolar disorder one of the main behavioral symptoms of bipolar disorder is abnormal sleep. studies have suggested that 23-78% of individuals with bipolar disorders consistently report symptoms of excessive time spent sleeping, or hypersomnia. the pathogenesis of bipolar disorder, including the higher risk of suicidal ideation, could possibly be linked to circadian rhythm variability, and sleep disturbances are a good predictor of mood swings. the most common sleep-related symptom of bipolar disorder is insomnia, in addition to hypersomnia, nightmares, poor sleep quality, osa, extreme daytime sleepiness, etc. moreover, animal models have shown that sleep debt can induce episodes of bipolar mania in laboratory mice, but these models are still limited in their potential to explain bipolar disease in humans with all its multifaceted symptoms, including those related to sleep disturbances. major depressive disorder (mdd) sleep disturbances (insomnia or hypersomnia) are not a necessary diagnostic criterion—but one of the most frequent symptoms of individuals with major depressive disorder (mdd). among individuals with mdd, insomnia and hypersomnia have prevalence estimates of 88% and 27%, respectively, whereas individuals with insomnia have a threefold increased risk of developing mdd. depressed mood and sleep efficiency strongly co-vary, and while sleep regulation problems may precede depressive episodes, such depressive episodes may also precipitate sleep deprivation. fatigue, as well as sleep disturbances such as irregular and excessive sleepiness, are linked to symptoms of depression. recent research has even pointed to sleep problems and fatigues as potential driving forces bridging mdd symptoms to those of co-occurring generalized anxiety disorder. treatment sign with text: sömnförsök pågår (sleep study in progress), room for sleep studies in näl hospital, sweden. treatments for sleep disorders generally can be grouped into four categories: behavioral and psychotherapeutic treatment rehabilitation and management medication other somatic treatment none of these general approaches are sufficient for all patients with sleep disorders. rather, the choice of a specific treatment depends on the patient's diagnosis, medical and psychiatric history, and preferences, as well as the expertise of the treating clinician. often, behavioral/psychotherapeutic and pharmacological approaches may be compatible, and can effectively be combined to maximize therapeutic benefits. management of sleep disturbances that are secondary to mental, medical, or substance abuse disorders should focus on the underlying conditions. medications and somatic treatments may provide the most rapid symptomatic relief from certain disorders, such as narcolepsy, which is best treated with prescription drugs such as modafinil. others, such as chronic and primary insomnia, may be more amenable to behavioral interventions—with more durable results. chronic sleep disorders in childhood, which affect some 70% of children with developmental or psychological disorders, are under-reported and under-treated. sleep-phase disruption is also common among adolescents, whose school schedules are often incompatible with their natural circadian rhythm. effective treatment begins with careful diagnosis using sleep diaries and perhaps sleep studies. modifications in sleep hygiene may resolve the problem, but medical treatment is often warranted. special equipment may be required for treatment of several disorders such as obstructive apnea, circadian rhythm disorders and bruxism. in severe cases, it may be necessary for individuals to accept living with the disorder, however well managed. some sleep disorders have been found to compromise glucose metabolism. allergy treatment histamine plays a role in wakefulness in the brain. an allergic reaction over produces histamine, causing wakefulness and inhibiting sleep. sleep problems are common in people with allergic rhinitis. a study from the n.i.h. found that sleep is dramatically impaired by allergic symptoms, and that the degree of impairment is related to the severity of those symptoms. treatment of allergies has also been shown to help sleep apnea. acupuncture a review of the evidence in 2012 concluded that current research is not rigorous enough to make recommendations around the use of acupuncture for insomnia. the pooled results of two trials on acupuncture showed a moderate likelihood that there may be some improvement to sleep quality for individuals with insomnia.: 15 this form of treatment for sleep disorders is generally studied in adults, rather than children. further research would be needed to study the effects of acupuncture on sleep disorders in children. hypnosis research suggests that hypnosis may be helpful in alleviating some types and manifestations of sleep disorders in some patients. "acute and chronic insomnia often respond to relaxation and hypnotherapy approaches, along with sleep hygiene instructions." hypnotherapy has also helped with nightmares and sleep terrors. there are several reports of successful use of hypnotherapy for parasomnias specifically for head and body rocking, bedwetting and sleepwalking. hypnotherapy has been studied in the treatment of sleep disorders in both adults and children. music therapy although more research should be done to increase the reliability of this method of treatment, research suggests that music therapy can improve sleep quality in acute and chronic sleep disorders. in one particular study, participants (18 years or older) who had experienced acute or chronic sleep disorders were put in a randomly controlled trial, and their sleep efficiency, in the form of overall time asleep, was observed. in order to assess sleep quality, researchers used subjective measures (i.e. questionnaires) and objective measures (i.e. polysomnography). the results of the study suggest that music therapy did improve sleep quality in subjects with acute or chronic sleep disorders, though only when tested subjectively. although these results are not fully conclusive and more research should be conducted, it still provides evidence that music therapy can be an effective treatment for sleep disorders. in another study specifically looking to help people with insomnia, similar results were seen. the participants that listened to music experienced better sleep quality than those who did not listen to music. listening to slower pace music before bed can help decrease the heart rate, making it easier to transition into sleep. studies have indicated that music helps induce a state of relaxation that shifts an individual's internal clock towards the sleep cycle. this is said to have an effect on children and adults with various cases of sleep disorders. music is most effective before bed once the brain has been conditioned to it, helping to achieve sleep much faster. melatonin research suggests that melatonin is useful in helping people fall asleep faster (decreased sleep latency), stay asleep longer, and experience improved sleep quality. to test this, a study was conducted that compared subjects who had taken melatonin to subjects with primary sleep disorders who had taken a placebo. researchers assessed sleep onset latency, total minutes slept, and overall sleep quality in the melatonin and placebo groups to note the differences. in the end, researchers found that melatonin decreased sleep onset latency and increased total sleep time but had an insignificant and inconclusive impact on the quality of sleep compared to the placebo group. sleep medicine main article: sleep medicine due to rapidly increasing knowledge and understanding of sleep in the 20th century, including the discovery of rem sleep in the 1950s and circadian rhythm disorders in the 70s and 80s, the