sleep needs no introduction every person on earth has had the experience of being asleep with most people spending up to a third of their lives in this state however for the purposes of clarity let's introduce some definitions sleep is a temporary state of decreased consciousness characterized by reduced wakefulness inhibition of most incoming sensory information and lowered muscle activity sleep allows the body to regenerate energy and restore tissues used during the day on a cognitive level sleep promotes memory formation by consolidating recently learned information the daily cycle of alternating between periods of sleep and wakefulness is known as the circadian rhythm this cycle is regulated by the hormone melatonin which is secreted at night by the pineal gland in response to low light in the environment melatonin decreases wakefulness and promotes sleep secretion of melatonin stops in the morning at which time the hormone cortisol is at its peak this alternation between melatonin and cortisol correlates with the subjective feelings of being awake or sleepy throughout a 24-hour period you can remember the function of both of these hormones by thinking that melatonin makes you want to turn in for the night while cortisol is released during the daytime in response to solar rays sleep itself is a dynamic process that ebbs and flows throughout the night even if we are not necessarily conscious of this sleep generally occurs in sleep cycles that last 90 minutes on average with most people having four to six sleep cycles per night sleep cycles involve a regular progression through various stages of sleep as seen in this figure with hours of sleep on the x-axis and stage of sleep on the y-axis each stage of sleep is characterized not only by changes in consciousness and behavior but also by a specific pattern of electrical activity in the brain which can be seen using an electroencephalogram or eeg a sleep cycle proceeds in a regular order from lighter stages of sleep stages 1 and 2 down towards deeper phases of sleep stages 3 and 4 which are associated with slower and less frequent activity on eeg the findings seen in each stage of the sleep cycle as well as the order they occur in can be memorized using the mnemonic bat's drink red blood first b is for beta waves the beginning of the sleep cycle is when someone is awake with beta waves being the pattern of electrical brain activity that occurs during waking consciousness next a is for alpha waves on average people take 15 minutes to fall asleep from the time they go to bed between wakefulness and sleep is an in-between state where one feels drowsy but remains conscious this state is characterized by alpha waves on eeg which reflects slowed brain activity compared to full wakefulness next t is for theta waves theta waves mark the time when someone crosses over from wakefulness into stage one sleep stage 1 sleep is also known as light sleep as someone is just barely asleep and is easily aroused by various stimuli like the sound of the television in the other room muscle tone is generally reduced although sudden muscle twitches known as hypnic jerks can occur next s is for sleep spindles and k complexes stage two sleep is characterized by a full absence of consciousness and a further decrease in muscle tone on eeg this appears in the form of specific patterns of electrical activity known as sleep spindles and k complexes next d is for delta waves the presence of low frequency delta waves characterizes deep sleep which you can remember by focusing on the first two letters of both delta and deep deep sleep is the most restorative phase of sleep both physically and mentally in this state someone becomes unaware of all but the most intrusive external stimuli for example outside traffic noise or the sound of a television are typically blocked out although louder noises like an alarm clock going off may break someone out of this stage of sleep next r is for rapid eye movement rapid eye movement or rem sleep which is named for the fact that someone's eyes are noted to move rapidly during this time even though the eyelids remain closed is a paradoxical stage of sleep in which the brain's level activity is increased to the point where it resembles an awake state on eeg all despite still being asleep this results in two distinct patterns that you should memorize as they will come up a few times when talking about sleep disorders later in this lecture luckily both of these patterns start with the letters rem first rem sleep is when you are most likely to remember your dreams as this is when the most dramatic dreaming occurs with some studies estimating that around 80 percent of all dreams occur during this stage despite all this mental activity someone in a state of rem sleep is likely to physically remain still as rem sleep is associated with muscle paralysis throughout the body with only the muscles of breathing and eye movement remaining active this widespread muscle paralysis is a good thing as without it we would likely act out our dreams at night and not get very much rest finally b is for back again following rem sleep the brain moves backwards through the previous stages of sleep and then begins another cycle this cycle between rem and non-rem sleep repeat several times per night after enough time the person spontaneously wakes up someone waking up from a lighter stage of sleep often feels more well-rested than if they'd woken up directly from deeper sleep at this point the amount of melatonin secretion is minimal while levels of cortisol are near their highest levels creating a sensation of alertness and wakefulness to prepare for the day ahead with that basic understanding of sleep physiology covered let's turn our attention to sleep disorders by far the most common form of sleep disorder is insomnia which is defined as any form of difficulty sleeping including trouble falling asleep awakening during the night or waking up earlier than desired insomnia is not inherently pathological and occasional nights of bad sleep are completely normal however if the inability to sleep continues for too long or becomes severe it can be the source of disability distress and dysfunction symptomatically people with chronic insomnia often struggle with fatigue poor mood irritability and inattention throughout the day patients with chronic insomnia often report feeling some level of distress or worry about their lack of sleep as well insomnia is common with around 30 of the population reporting problems with sleep on at least an occasional basis for this reason insomnia should not be considered a disorder until it becomes frequent and severe most cases are secondary with insomnia being caused by upstream factors like lifestyle drugs or other disorders once these have been excluded the prevalence of primary insomnia falls to around five percent of the general population age and gender are the largest risk factors for insomnia with older adults and women both being at higher risk compared to the rest of the population the presence of a comorbid psychiatric disorder is also a major risk factor with studies showing that around 40 of all people with recurrent insomnia meet criteria for at least one mental disorder compared to only 15 of people without sleep complaints of these depression is the most common although anxiety is a close second as a general rule insomnia tends to be persistent although it may come and go in an episodic fashion for some patients chronic insomnia is associated with worse outcomes in nearly all areas of one's life including physical health mental well-being pain perception and levels of social support physical and cognitive performance decreases as well with patients who miss even one night of sleep driving just as badly if not worse than someone who is under the influence of alcohol in fact people who are chronically sleep deprived have a rate of accidents that's up to five times higher than the average all of these together predict a greatly increased risk of mortality with severe insomnia or sleeping less than four hours a night being associated with a fifteen percent higher mortality rate treatment of insomnia involves therapy medications or both the first line treatment should be a type of cbt known as cognitive behavioral therapy for insomnia or cbti cbti involves practicing good sleep hygiene combined with addressing and correcting any dysfunctional beliefs that may be contributing to sleep-related anxiety such as countering the incredibly common though completely inaccurate belief that if you don't get enough sleep on any particular night then you're going to have a terrible time the next day cbti has been associated with major reductions in the subjective sleep related distress that a patient experiences as well as lesser those still significant objective improvements in the amount and quality of sleep that they get in addition the beneficial effects of cbti tend to persist even after treatment has ended medications used to treat insomnia are known as hypnotics and consist of a wide variety of drugs with different mechanisms of action including antihistamines like diphenhydramine or benadryl benzediazepines like lorazepam or adiban and z drugs like zolpidem or ambien while the efficacy of these drugs varies depending on the class as a whole their effects tend to be limited to the time in which they're taken and people often develop tolerance to their sedative effects after only a few nights of regular use furthermore hypnotics can cause daytime sedation and poor balance leading to an increased risk of falls especially in the elderly for this reason hypnotic drugs should generally be recommended only after other interventions such as cbti have been tried and even then they should be prescribed for as short a period of time as possible in addition to primary insomnia there are a few other disorders that can impact the amount or quality of sleep that a person gets let's go over a few of the highest yield disorders to know as we close out this lecture first obstructive sleep apnea or osa is a condition in which people suffer from brief but recurrent episodes of apnea or pauses and breathing throughout the night this occurs as a result of anatomical blockage of the airways due to both the muscle relaxation that occurs during sleep as well as the recumbent position that most people sleep in these hypoxic episodes lead to transient micro awakenings that occur throughout the night and prevent the person from entering into deep sleep resulting in sleep that is not restorative this leads to persistent daytime fatigue and other symptoms such as headaches while intuitively it would seem like the sleep disruption seen in this disorder would make people more able to fall asleep at night studies have shown that as many as half of all people with osa still struggle with bedtime insomnia for this reason make sure to ask about osa and anyone presenting with chronic fatigue as patients are not always aware that they are waking up frequently at night you can use the mnemonic stop bang to remember the specific factors that are predictive of osa including snoring loudly feeling tired all the time apnic episodes that have been directly observed by someone else high blood pressure high body mass index older age a large neck circumference and male gender osa is a major threat to health as untreated cases are associated with a higher risk of heart attack and stroke treatment for osa involves using a continuous positive airway pressure or cpap machine that provides a steady stream of air to keep the airway from getting compressed next restless leg syndrome or rls is a condition in which a person experiences recurrent feelings of restlessness while trying to sleep you can remember the key clinical features using the mnemonic urge which will remind you that patients feel an urge to move their legs that this urge not only worsens with rest but also gets better with activity like moving one's legs and that the feeling is more pronounced in the evening when trying to sleep restless leg syndrome can impair both the amount and quality of sleep leading to symptoms of sleep deprivation around half of all cases of restless leg syndrome are idiopathic with genetics playing a large role however it can also occur as a result of other medical or psychiatric conditions the most common culprit is iron deficiency which is seen in about 20 of all cases for idiopathic cases no curative treatments are available instead a variety of symptomatic treatments can help to improve sleep duration and quality of life you can remember these using the mnemonic laid which stands for lifestyle changes including sleep hygiene caffeine avoidance and smoking cessation anti-convulsions and specifically gabapentin or pregabalin which are a good first line option for medication treatment iron supplementation in cases where iron deficiency is involved and finally dopamine agonists like pramipexole or ropinirole although these drugs are used less often these days as despite being effective in the short term they often make restlessness worse in the long term and come with some pretty severe side effects by considering these treatment strategies you can make sure that the patient's rls has been laid to restless next people who are not able to consistently follow a set daily schedule such as those who work night shifts or travel across time zones are at risk for circadian rhythm disorders often just called jet lag these disorders are characterized by excessive sleepiness during the day time when they should be awake and involuntary wakefulness at night when they should be asleep providing education on sleep hygiene such as avoidance of naps and caffeine prior to sleep can be an initial first step for those with excessive difficulty falling asleep at night melatonin supplements can be incredibly helpful for those with difficulty staying awake during the day exposure to bright lights can be effective as can the medication modafinil which helps to promote wakefulness next sleepwalking also called somnambolism is when an individual performs activities as if they are awake despite being in a state of deep sleep this most commonly involves walking around although other activities such as going to the bathroom cooking and even driving have been reported sleepwalking is a type of parasomnia a category of sleep disorders characterized by abnormal movements or behaviors during sleep parasomnias like sleepwalking occur during slow wave sleep when muscles are not paralyzed like they are during rem sleep most cases of sleepwalking are idiopathic with no clear cause ever being found however in some cases they may be related to use of z drugs like zolpidem the next three disorders we'll talk about all involve unpleasant or even terrifying experiences that occur around sleep first is nightmare disorder which naturally occurs during rem sleep when people are most likely to remember their dreams most people have nightmares from time to time but a minority of people are afflicted by nightmares that are frequent or severe enough to qualify as a disorder people with nightmare disorder are more likely to have a history of trauma if treatment is desired stress reduction techniques such as mindfulness can help as can the medication prasa sin which has been shown to reduce the frequency and severity of nightmares next sleep terrors also called night terrors differ from nightmares and that they occur during non-rem sleep and the patient is usually unable to remember what they were dreaming about however upon awakening they are clearly distressed often crying out or sitting upright with eyes wide open physiologic signs can resemble a panic attack with tachycardia and hyperventilation being common sleep tears most often occur during childhood and the majority of cases do not persist into adulthood with less than one percent of adults experiencing sleep terrors on a regular basis for this reason reassurance is typically sufficient treatment for children who suffer from sleep tears as well as their parents capping off the trio of conditions involving terrifying experiences while sleep is sleep paralysis sleep paralysis occurs when someone wakes up from rem sleep and gains consciousness of the world but remains unable to move this sensation is often accompanied by a feeling of fear or panic in addition many people report a distinct sensation of being watched and can even hallucinate a malevolent figure in the room in this way we see what happens when the two components of rem sleep remembering dreams and remaining still persist even after the patient has woken up they are still paralyzed and in a hallucinatory dream state but they are now conscious of it resulting in a terrifying experience episodes of sleep paralysis can be highly disturbing especially if they are so frequent or severe that the patient develops anxiety about going to bed up to half of all adults have experienced at least one episode of sleep paralysis although less than five percent experience them on a regular basis education on the nature of sleep paralysis and teaching of relaxation techniques can often be treatment enough although in more severe cases cbt or serotonin boosting medications like ssris can be used the last two disorders we'll talk about also involve abnormalities of the rem sleep state first rem sleep behavior disorder is characterized by abnormal movements during rem sleep as the remaining still part of rem sleep has been lost while the remembering dreams part remains this lack of muscle paralysis during rem sleep leads to the patient acting out their dreams which can be very disruptive to others share in the bed in patients with rem sleep behavior disorder can sometimes even unintentionally injure themselves or their partners if they are experiencing a particularly violent dream rem sleep behavior disorder rarely occurs on its own with more than 90 of patients going on to have a neurologic disorder with parkinson's disease and dementia with lewy bodies being common melatonin is a good first-line option for treatment as it is both effective and well tolerated taking steps to make the sleep environment safer such as putting another mattress on the ground in case the patient rolls off the bed can also help to prevent against injuries finally narcolepsy is a neurological disorder characterized by both excessive daytime sleepiness and abnormalities of rem sleep that result in a set of highly characteristic signs and symptoms the mnemonic chap will help you remember these first c is for cataplexy cataplexy refers to sudden episodes of muscle paralysis during wakefulness this can span the range from more subtle signs such as slight weakness in one's limbs all the way up to more dramatic events such as collapsing on the ground due to a complete loss of muscle tone cataplexy is often triggered by strong emotional states but it can occur out of the blue as well cataplexy is caused by sudden daytime activation of the same remaining still muscle paralysis seen in rem sleep and is one manifestation of the rem sleep abnormalities seen in this disorder cataplexy is unique to narcolepsy making it a very specific sign of this disorder next h is for hypnagogic and hypnopomic hallucinations the term hypnagogic refers to the transition from wakefulness to sleep while hypnopompic refers to the transition from sleep to wakefulness you can remember this difference between hypnagogic and hypnopomic hallucinations by thinking that hypnograogate hallucinations occur when you're groggy at night while hypnopic hallucinations happen when you need to pump yourself up in the morning people with narcolepsy are known to experience vivid hallucinations during both of these sleep transitions this imagery can range from random lights or speckles all the way to fully formed images of people and places in this way hypnagogic and hiptopic hallucinations represent yet another way in which narcolepsy involves abnormalities of the rem sleep state as patients experience the remembering dreams part even though they are still partially awake next a is for sleep attacks one of the core features of narcolepsy is excessive daytime sleepiness which is experienced even when the patient gets enough sleep at night for some patients the drive towards sleep becomes so strong that they have episodes of suddenly falling asleep without intending to sometimes even while walking driving or doing other activities these sleep attacks typically last only a few seconds or minutes but due to their unpredictable nature they can be incredibly distressing and impairing while sleep attacks are perhaps the most dramatic and well-known sign of narcolepsy not all people with this disorder experience them finally p is for sleep paralysis episodes of sleep paralysis as described earlier in this lecture are common in narcolepsy and like the other signs of this disorder represent a manifestation of the tendency these patients have towards experiencing alterations of rem sleep with remembering dreams and remaining still happening even after the patient wakes up while diagnosing narcolepsy is easy when someone has all four of these clinical features not everyone with narcolepsy does in cases where the diagnosis is less clear sleep studies can help to detect the specific abnormalities such as rapid transitions between wakefulness and rem sleep that characterize narcolepsy narcolepsy is a rare diagnosis affecting less than 0.1 percent of the population although it may be under-diagnosed especially in people who do not have all four of the characteristic signs and symptoms it tends to have its onset during adolescence and early adulthood with men and women being affected equally narcolepsy is a lifelong condition that can result in ongoing distress and disability if left untreated no definitive cure exists so treatment is focused instead on managing the symptoms to enable the patient to live a decent life sodium oxibate better known by its street name gamma hydroxybutyric acid or ghb is effective at reducing the severity of multiple symptoms of narcolepsy including excessive daytime sleepiness episodes of cataplexy and altered sleep architecture conversely the wakefulness enhancing drug modafinil is effective at reducing daytime sleepiness and sleep attacks but does not significantly affect episodes of cataplexy careful maintenance of sleep hygiene and avoidance of sleep impairing substances like caffeine and alcohol are crucial as well behavioral and lifestyle changes such as scheduling naps and exercise sessions can also be beneficial and with that we have completed our introduction to the world of both sleep and its associated disorders sleep is a vital part of life that is essential not only for living but for living well because of the close relationship of sleep to both physical and mental health consider making an assessment of the patient's sleep patterns a core part of every medical evaluation as there's often a lot that can be done to help the patient improve not only the quality of their sleep but also the quality of their life as well and that's it i hope you've enjoyed this lecture series i'm happy to make the core content from my memorable psychiatry book available for free in this video lecture format for whoever wants to watch it for anyone who wants to engage with this material at a higher level i recommend picking up the book that these videos are based on as it contains richer discussions of each disorder as well as questions to test new knowledge and get you ready for clinical practice i'm hoping to release some more videos soon so please subscribe to the channel in the meantime i wish you the best in your studies bye for now