Common sleep disorders can significantly impact an individual’s overall health and well-being. Insomnia, a prevalent sleep disorder, involves dissatisfaction with sleep quality or quantity, often manifesting as difficulty falling asleep, staying asleep, or early morning awakenings without the ability to return to sleep. Sleep apnea, another common disorder, results in pauses in breathing or shallow breaths during sleep, disrupting the sleep cycle and causing excessive daytime sleepiness.
Narcolepsy is a neurological disorder that affects sleep and wakefulness, leading to excessive sleepiness and frequent daytime sleep episodes. These sudden attacks can occur at any time during the day, interfering with daily activities. Diagnosis of these sleep disorders requires that the sleep disturbance causes distress or impairment in functioning and occurs frequently over a period of time.
Insomnia can be a symptom, a risk factor, or an independent disorder, and it can often be comorbid with other sleep disorders or medical conditions such as sleep apnea, depression, anxiety, or chronic pain. Treatment approaches for insomnia include pharmacotherapy and behavioral interventions, with cognitive-behavioral therapy for insomnia (CBT-I) being a common and effective treatment option. However, insomnia associated with significant comorbidities may require a combination of medication, behavioral therapy, and referrals to specialized sleep medicine clinics for comprehensive management.
Sleep architecture refers to the orderly progression of sleep stages in cycles lasting approximately 90-120 minutes. These cycles are crucial for understanding the physiology of sleep. The initial stage involves transitioning from wakefulness to light sleep, characterized by generalized slowing of EEG activity and occasional hypnic jerks. As sleep deepens, sleep spindles and K-complex waveforms appear, marking the onset of deeper sleep. The deepest stage of NREM sleep, known as N3, is characterized by synchronized delta waves dominating the EEG. This stage is essential for physical restoration, immune function, and memory consolidation.
REM sleep, often referred to as dream sleep, involves vivid dreaming and increased brain activity resembling wakefulness. However, during REM sleep, the body experiences muscle atonia, preventing physical movement during dreams. Sleep is regulated by various neurochemicals, including serotonin, dopamine, norepinephrine, and acetylcholine.
Circadian rhythms, controlled by the suprachiasmatic nucleus in the brain, regulate the sleep-wake cycle based on external cues like light and darkness. Sleep efficiency tends to decline gradually with age, affecting the timing and quality of sleep. Polysomnography (PSG) is a diagnostic tool used to evaluate sleep disorders by recording various physiological parameters during sleep. The diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) classified sleep disorders into three major categories: insomnia, hypersomnia, and arousal disorders. This classification was expanded in the DSM-V these are described with examples in table 1. Primary sleep disorders, which include dyssomnias and parasomnias, are characterized by abnormalities in the sleep-wake cycle or circadian rhythm and are not associated with other medical or psychiatric conditions.
Table 1. Classification of Sleep Disorders.
| Sleep Disorders | Description | Examples |
|---|---|---|
| Insomnia Disorders | Focuses on difficulty initiating or maintaining sleep. | onset insomnia, maintenance insomnia, behavioural insomnia of childhood |
| Hypersomnolence Disorders | Excessive daytime sleepiness despite sufficient sleep opportunities. | narcolepsy, idiopathic hypersomnia, Kleine-Lewin Syndrome, drug induced hypersomnia, hypersomnia associated with psychiatric disorders. |
| Breathing-Related Sleep Disorders | Breathing disorders impacting nighttime breathing patterns and sleep quality. | central sleep apnea, obstructive sleep apnea, upper airway resistance syndrome, sleep related [hypoventilation, hypoxemia] disorders. |
| Circadian Rhythm Sleep-Wake Disorders | Result from disturbances in the body’s internal clock. | advanced/delayed sleep-wake phase, irregular sleep-wake rhythm, shift work, jet lag disorders. |
| Non-REM Sleep Arousal Disorders | Abnormal behaviours or experiences while in a state of partial arousal during non-REM sleep. | sleep walking, night terrors. |
| REM Sleep Behaviours Disorders | Vivid dreaming, lack of muscle atonia, individuals physically act out their dreams, which can lead to injury or harm. | vocal sounds (talking, shouting, cursing), movements (kicking, punching, jumping), violent defensive actions. |
| Nightmare Disorder | Repeated occurrences of extended, extremely dysphoric dreams involving threats to survival, security, or physical integrity. | |
| Restless Leg Syndrome | An irresistible urge to move the legs, often accompanied by uncomfortable sensations. | |
| Substance or Medication-Induced Sleep Disorder | Sleep disturbances caused by substance use (e.g., alcohol, medications). |
Sleep disorders affect a significant portion of the population, impacting overall health and well-being. Approximately 50 to 70 million Americans suffer from sleep or wakefulness disorders, encompassing a wide range of conditions affecting sleep quality, duration, and overall well-being. Insomnia is one of the most common sleep disorders, with 40% to 60% of adults in the US reporting symptoms. Among these, more than 10% experience chronic insomnia, persisting over an extended period. Sleep patterns and disorders vary across age groups. While adults aged 18 to 64 generally meet sleep duration recommendations, older adults aged 65 and older tend to have slightly longer sleep duration but may experience more variability in sleep quality.
Insomnia is a prevalent complaint in general medical practice, causing distress due to difficulty falling asleep, maintaining sleep, or experiencing nonrestorative sleep. It significantly impacts work-related productivity due to daytime fatigue or drowsiness. While transient insomnia lasts for a few nights, acute insomnia resolves within three weeks to less than three months. Chronic insomnia, lasting longer than three months, affects around 9% to 12% of adults and up to 20% of the elderly. More than 50% of the population experiences insomnia at some point in their lives, with one-third reporting insomnia symptoms and 17% describing them as severe. Women report insomnia twice as frequently as men, and individuals who are elderly, unemployed, separated, widowed, or have a lower socioeconomic status are more prone to insomnia. Approximately 40% of individuals with insomnia have a concurrent psychiatric disorder, such as anxiety, depression, or substance abuse.
Despite its prevalence, only 5% of individuals seek medical attention for insomnia management. About 10% to 20% use nonprescription drugs or alcohol to self-treat, while 3% are prescribed sedative-hypnotics for insomnia, with 11% reporting long-term use. Primary insomnia, considered an endogenous disorder, can be caused by neurochemical or structural issues affecting the sleep-wake cycle. Patients with primary insomnia are often easily aroused and may have increased metabolic rates, leading to prolonged sleep onset. Evaluation of transient or short-term insomnia should focus on recent stressors, while chronic insomnia may be associated with psychiatric or medical conditions. A comprehensive diagnostic examination is essential to rule out other sleep disorders like restless legs syndrome, periodic limb movements of sleep, or sleep apnea, which can present with similar symptoms
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