Insomnia Prevalence, Health Effects, and Treatment Options

Introduction

Everyone experiences trouble sleeping from time to time. The events of a busy day can easily intrude on sleep to the point where people fail to get enough rest, and the ongoing COVID-19 pandemic has added further fuel to these sleep-disrupting fires. When people consistently fail to get enough sleep over sustained periods, however, they can suffer from a wide range of physical and mental health disorders with life-changing implications. Although greater attention has been focused on sleep disorders such as insomnia in recent years, far too many people continue to suffer from this common but potentially harmful condition.

This evidence synthesis paper provides a review of the relevant literature concerning the prevalence of insomnia among American adults, a summary of the adverse mental and physical health problems the disorder can cause, and an overview of the pharmacological and behavioral interventions identified as most efficacious for its treatment.

Like fire and dark energy, sleep remains a mysterious phenomenon in many ways. Despite being the focus of a growing body of research over the past several centuries, much still remains unknown or unclear about sleep and its role in human physiology. Moreover, numerous misconceptions and myths about sleep may prevent people from seeking professional assistance for disordered sleep. According to the American Sleep Association (2020), "Prior to the mid-20th century, researchers conceptualized sleep as a 'passive, dormant part of our daily lives,' but fast forward 70 years and we now know that our brains are very active during sleep" (What is sleep and why is it important?, para. 2).

Although there is no universally accepted definition, two representative definitions of sleep include the following:

1. A condition of body and mind such as that which typically recurs for several hours every night, in which the nervous system is relatively inactive, the eyes closed, the postural muscles relaxed, and consciousness practically suspended (Google Dictionary).

2. The natural, easily reversible periodic state of many living things that is marked by the absence of wakefulness and by the loss of consciousness of one's surroundings, accompanied by a typical body posture (such as lying down with the eyes closed), the occurrence of dreaming, and changes in brain activity and physiological functioning, made up of cycles of non-rapid eye movement (non-REM) sleep and REM sleep, and usually considered essential to the restoration and recovery of vital bodily and mental functions (Merriam-Webster).

The first definition is more closely aligned with the conceptualization of passive sleep that prevailed prior to the 1970s, while the second takes into account the elevated brain activity that occurs during REM sleep. This evolution in the precision of sleep's definition may have also affected the reported prevalence of sleep-related disorders such as insomnia by raising consumer awareness — an issue discussed further below.

Prevalence of Insomnia

At the global level, insomnia is widely prevalent and has been reported to affect up to 33% of the adult population (Sharma & Andrade, 2017). Some researchers estimate the global prevalence even higher. Bhaskar, Hemavathy, and Prasad (2016) report that "various studies worldwide have shown the prevalence of insomnia in 10%–30% of the population, some even as high as 50%–60%" (p. 780). Although anyone can suffer from insomnia, the elderly and those with preexisting mental health and medical disorders are at especially high risk (Sharma & Andrade, 2017).

Domestically, the prevalence of insomnia is somewhat lower than the global estimate. Using a definition aligned with DSM-V diagnostic criteria, researchers at the Perelman School of Medicine found that approximately one in four American adults — about 75 million people — develop acute insomnia annually. However, a majority of these new cases (approximately 75%, or 56.25 million people) successfully recover from these transient episodes without progressing to chronic sleep disorders (Perlis, 2018). Based on an analysis of a sample of 1,435 adults, Perlis (2018) and associates concluded that "whether caused by stress, illness, medications, or other factors, poor sleep is very common" (para. 4).

Beyond the human toll of insomnia, there is also a significant economic burden associated with treating the disorder. According to Alexandru and Róbert (2009), the cost of treatments for insomnia patients in the United States reached more than $2.1 billion in 2004 and grew to more than $3.2 billion by 2009. While the direct treatment costs can be quantified, the lost productivity, diminished performance, and increased absenteeism attributable to chronic insomnia are far more difficult to measure — yet these costs are believed to be staggering in their adverse effects on individuals and the national economy (Alexandru & Róbert, 2009). Reddy and Chakrabarty (2011) found that "while 30–48% of individuals report some problem sleeping in a year, when diagnostic criteria were used for insomnia syndrome, 6% of respondents indicated a disorder of insomnia that impaired daytime function" (p. 3).

These adverse effects underscore the importance of securing sufficient restful sleep each night. The Mayo Clinic identifies the following common symptoms of insomnia:

Despite its increased prevalence and potential to cause serious health problems, insomnia has historically received scant clinical attention (Sateia et al., 2000). Some of the research concerning insomnia has also been characterized by disparities attributable to a lack of definitional clarity. Insomnia has been alternatively described as dissatisfaction with sleep, with or without daytime consequences, or as insomnia disorder. The current DSM-V diagnostic criteria for insomnia are provided in Appendix A. These criteria are similar to those set forth in the International Classification of Sleep Disorders, which specify that "symptoms must cause clinically significant functional distress or impairment, be present for at least 3 nights per week for at least 3 months, and not be linked to other sleep, medical, or mental disorders" (Bhaskar et al., 2016). Without this type of uniform diagnostic framework, results across sleep disorder studies will vary in documented cases and overall prevalence.

What is known with some degree of certainty is that the increased prevalence of insomnia over the past 20 years has been linked to increases in prescription medication use (Bertisch, Herzig, & Winkelman, 2014). Between 50% and 80% of patients seeking clinical assistance report having experienced significant problems falling asleep and staying asleep at some point during the preceding year (Bertisch et al., 2014). A growing body of research confirms that sleep has a profound impact on mental and physical health, though additional research in these areas is still needed.

Adverse Physical and Mental Health Effects

Insomnia is one of the most common types of sleep disorders, and a growing body of evidence confirms that people who suffer from it are at greater risk of experiencing a mood disorder or the recurrence of an existing disorder, as well as exacerbated psychiatric symptoms including mania and depression (Khawaja & Hurwitz, 2017). Other problems frequently associated with poor sleep include anxiety, chronic illness, inadequate physical exercise, and the side effects of certain medications (Sateia, Buysse, Krystal et al., 2000).

One of the more challenging aspects of assessing these adverse effects is that sleep needs differ significantly between individuals. Some people appear to require far more or far less sleep than others to maintain normal day-to-day functioning. Even when a sleep disorder does not satisfy all DSM-V diagnostic criteria, diminished or interrupted sleep patterns can still have severe mental and physical health consequences.

In an effort to develop broadly applicable findings to guide clinical practice, researchers at the U.S. Centers for Disease Control and Prevention (CDC) used 7 hours of sleep per night as the benchmark for the minimum daily requirement for adults and evaluated the effects of sleep deprivation similar to those experienced in insomniac cases. Their findings were alarming: people who fail to get at least 7 hours of sleep per night are at greater risk of heart attack, stroke, coronary heart disease, asthma, chronic obstructive pulmonary disease, cancer, arthritis, chronic kidney disease, and diabetes, in descending order of risk (Short sleep duration among American adults, 2020).

Taken together, it is clear that obtaining sufficient restful sleep is a critically important component of human health, and there are evidence-based interventions that can help address this need.

Conclusion

The research showed that obtaining a sufficient amount of restful, REM sleep each night is essential for maintaining good mental and physical health. The research also showed, however, that the frail human condition is replete with events that intrude on individuals' ability to get to sleep and stay asleep for the full 7 hours recommended for adults by the CDC. In sum, and to paraphrase Hamlet, "To sleep, perchance to dream — ay, there's the rub." Even under the best of circumstances, the human brain is a relentlessly busy machine, constantly producing neural activity during sleep that manifests in infinite ways — which accounts, in part, for the increased prevalence of insomnia in the United States in recent years. Improvements in definitional clarity with respect to insomnia disorder have also contributed to this increase by helping clinicians better diagnose the condition.

The research was consistent in showing that several evidence-based behavioral and pharmacological interventions have been used to treat insomnia disorder with varying degrees of effectiveness, suggesting there is no "one-size-fits-all" treatment strategy appropriate for all adult insomniacs. In the final analysis, it is reasonable to conclude that the prevalence of insomnia in the United States will continue to escalate in the absence of the social, political, and economic stability that supports regular sleep patterns. Even under optimal circumstances, most people will experience trouble sleeping at some point in their lives, but the vast majority manage to overcome these transient episodes and return to normal sleeping patterns. Clinicians should therefore remain vigilant concerning new evidence-based behavioral and pharmacological interventions that can be used to treat insomnia and help patients regain a healthy lifestyle that includes sufficient amounts of sleep.

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A. A predominant complaint of dissatisfaction with sleep quantity or quality, associated with one or more of the following symptoms:

B. Difficulty initiating sleep. (In children, this may manifest as difficulty initiating sleep without caregiver intervention.)

C. Difficulty maintaining sleep, characterized by frequent awakenings or problems returning to sleep after awakenings. (In children, this may manifest as difficulty returning to sleep without caregiver intervention.)

D. Early-morning awakening with inability to return to sleep.

E. The sleep difficulty is present for at least 3 months.

Source: Adapted from https://www.ncbi.nlm.nih.gov/books/NBK519704/table/ch3.t36/