Sleep Deprivation

Etiology

Sleep loss has many causes and is generally multifactorial. Common contributing causes of sleep loss are sleep apnea, insomnia, restless leg syndrome, parasomnias, mood disturbances, psychosis, and other psychiatric, neurological, & medical conditions. When assessing the cause(s) of sleep loss, it is essential to address any of these underlying factors directly. Providers should not treat symptoms if they identify an underlying treatable cause. If the provider is unable to identify any contributing factors, the default diagnoses are primary insomnia. Primary insomnia is most common in elderly populations. As people age, the sleep architecture changes; delta-wave (or deep) sleep decrease, and the proportion of time spent in lighter sleep increases; this results in increased sleep disruptions.[1] The duration of sleep also decreases with age. Comorbid medical conditions can be both the cause and the effect of chronic sleep loss. For instance, a patient can develop obesity, which results in obstructive sleep apnea. The lack of quality sleep then leads to increased serum cortisol levels, which facilitates further weight gain. 

Epidemiology

Sleep loss is a pervasive problem that increases in frequency as individuals age. As the proportion of geriatric persons increases in the population in the U.S. and worldwide, the prevalence of sleep disorders will increase. Other causes of sleep loss, such as obesity, which leads to obstructive sleep apnea, are also on the rise.[2][3] Studies have found that sleep loss is more common than previously thought. Estimates are that 50 to 70 million Americans suffer from some form of sleep loss.[4] The drivers behind the recently increased prevalence of sleep loss include several broad societal changes, including working longer hours, shift work, and having greater access to television & the internet. Adults today are sleeping less to get more work done and staying up late to watch TV or use the Internet. A recent study found in people ages 25 to 45 years old, 20% were consistently sleeping 90 minutes less than was needed to maintain good health. [5] The problem of inadequate sleep is likely to increase due to our society's 24/7 nature, with activities to do at all hours and increased access to night time use of computers, mobile phones, and television. Studies have found that there has been a decline in the amount of sleep of up to 18 minutes per night over the last three decades.[6][7]  Epidemiological studies may inaccurately depict this problem as data is collected by self-report methods, which do not differentiate between time asleep and time in bed. Polysomnography is accurate but is expensive and time-consuming to utilize in extensive epidemiological studies. A new, cheaper method to collect data on sleeping habits involves the use of actigraphy.[8]

Pathophysiology

Chronic sleep deprivation has significant adverse effects on health and overall quality of life. Chronically sleep-deprived individuals had significantly lower reported markers of quality of life on a 36-item survey.[1] The survey looked at areas one's ability to function throughout the day, health problems, perception of pain, the general perception of one's health & vitality, social functioning, and mental health. 

Interestingly, many conditions that are commonly comorbid with sleep deprivation are associated with similar physiological states. Chronic sleep deprivation is associated with elevated cortisol and decreased testosterone levels. Testosterone is known to enhance the function of the gamma-aminobutyric acid (GABA) and serotonin systems in the brain. This reduced function provides one possible causal link between two of the most commonly associated psychiatric disorders, depression, and anxiety. Also, elevated serum cortisol levels have correlations with depression, anxiety, hypertension, obesity, and diabetes type II. Chronic sleep deprivation correlates with increased inflammatory markers, which is associated with all the above-mentioned comorbid conditions and psychosis. 

It is essential to realize that the body has many of the same physiological markers in chronic sleep deprivation as it does with its many comorbid conditions. Many of these physiological states provide the causal link between sleep deprivation and these other psychiatric and medical conditions. This cause and effect relationships are reciprocal, making chronic sleep deprivation a potential cause and result of these other conditions. It is of paramount importance to ensure a patient is getting adequate quality sleep when treating these conditions.

History and Physical

It is vital to assess a person’s quality and quantity of sleep. Seven to eight hours and nine hours of sleep are generally ideal for adults and adolescents, respectively. Less sleep correlates with obesity, diabetes & impaired glucose tolerance, cardiovascular disease & hypertension, anxiety and depressive symptoms, and alcohol use.[1] The presence of these ailments could serve as indicators that a patient may have an impaired quality of sleep. As a rule of thumb, the sicker the patient, the less likely it is that the patient sleeps well. 

When taking a history, essential questions to ask to assess a patient's sleep are:

Do you have trouble falling asleep? Staying asleep? Do you feel tired upon waking from sleep?

If the patient answers affirmatively to any of these questions, follow up with: Do these problems with sleep occur despite adequate time and opportunity for rest? Is the sleep difficulty impairing your functioning during the day? Do you feel distressed from the lack of quality sleep?

It is also essential to make an inquiry regarding the severity and frequency of these symptoms.[1] A patient who lacks adequate sleep will commonly endorse symptoms of sleep loss, such as excessive daytime sleepiness, poor concentration, fatigue, moodiness, and decreased libido, among other symptoms.[9] Be sure to optimize the patient's sleep before focusing on symptom relief. Again, correct the cause, not the symptom.

Evaluation

Upon determination of the poor quality of sleep, further evaluation is needed to determine potential causes of sleep loss. There will generally be more than one cause contributing to the loss of sleep. It is better to treat the causes directly. If obstructive sleep apnea (OSA) is a cause of quality sleep loss, it is best to address this with CPAP and/or weight loss. Ignoring the contribution of OSA to the sleep disturbance and prescribing sedating sleep aids could worsen the OSA and quality of sleep. It is also important to identify the symptoms the patient may be experiencing from sleep loss. The symptoms the patient suffers from should be monitored to assess treatment progress. The most common symptom of sleep loss is excessive daytime sleepiness. Also, patients can display depressed mood, poor focus, and impaired memory. Lack of sleep can also exacerbate psychiatric and medical conditions such as OSA, obesity, hypertension, depression, anxiety, etc. Lack of sleep will impair executive functions.[10] After optimizing sleep by addressing all the contributing factors, it is crucial to re-evaluate the patient for residual symptoms. At this time, symptomatic relief can be the focus. 

Treatment / Management

Despite the significant toll sleep loss places on public health, it is not often addressed by clinicians. To date, there are no formal treatment guidelines. However, there are many effective ways to treat sleep loss.

Treatment for sleep consists of three general approaches:

1. Behavioral modification/improving sleep hygiene
2. Treating causative medical and psychiatric conditions
3. Pharmacotherapy

It is important to review proper sleep hygiene with the patient to eliminate behavioral habits that adversely affect sleep. As mentioned previously, many of the comorbid medical and psychiatric conditions can be contributing to the trouble with sleep. The individual treatments for all these comorbidities are beyond the scope of this article. If the first two treatment options fail to resolve the sleep difficulties, one can consider pharmacotherapy. The clinician should be judicious when using medications as sleep aids because they can have unintended adverse effects. Certain medications can worsen daytime fatigue if given at too high a dose or if the medication half-life is too long. Sedating sleep aids can also exacerbate the conditions causing poor sleep. OSA can be worsened by sleep aids that promote weight gain and further relax the muscles around the airway during rest.

If sleep loss is a result of a lifestyle that cannot be changed (e.g., shift work), the provider can address excessive daytime sleepiness by giving specific behavioral tips to help individuals stay alert. Medications that promote wakefulness, such as caffeine, modafinil, and methylphenidate, are options. Currently, modafinil is the only medication that is FDA approved for shift work sleep disorder, but not sleep loss.[11](A1)

Differential Diagnosis

Sleep loss is a symptom, and to appropriately treat it, it is vital to discern between the many potential causes, which include:

• Primary insomnia
• Depression
• Anxiety
• Obstructive sleep apnea
• Obesity
• Substance abuse
• Chronic pain

Conditions that can mimic the symptoms of sleep loss are:

• Chronic fatigue syndrome
• Narcolepsy
• Substance abuse
• Depression
• Anxiety

Prognosis

If a healthcare provider appropriately identifies sleep loss, treatment can be successful, and the patient can resume a healthy lifestyle. 

Complications

Lack of adequate sleep can lead to many complications. Some of these complications can lead to further difficulty in getting sleep. Lack of sleep causes elevated cortisol, which can result in increased blood sugar, increased blood pressure, cravings for carbohydrates, and sugar, which leads to weight gain and other medical and psychiatric complications. The subjective experience of sleep loss can be distressing, which can exacerbate complications. The following is a non-comprehensive list of complications of sleep loss:

• Diabetes/insulin resistance
• Hypertension
• Obesity
• Obstructive sleep apnea
• Vascular disease
• Stroke
• Myocardial infarct
• Depression
• Anxiety
• Psychosis