Key Takeaways
  • Excessive daytime sleepiness is a symptom of an underlying health issue.
  • The most common cause of excessive daytime sleepiness is sleep deprivation.
  • Some medications, including sedatives, can also cause excessive sleepiness.
  • Other causes include mental health disorders, neurodegenerative diseases, and neurodevelopmental disorders, such as ADHD and autism.

The most common causes of excessive sleepiness are sleep deprivation and disorders like sleep apnea and insomnia. Depression and other mental health conditions, certain medications, and medical conditions affecting the brain and body can cause daytime drowsiness as well.

Recognizing excessive daytime sleepiness (EDS) is a first step toward addressing the problem. Working with a doctor to identify its cause and improve sleep habits can enhance your daily productivity, mood, and overall health.

What Is Excessive Daytime Sleepiness?

Excessive daytime sleepiness is not a condition in itself. Rather, it is a symptom caused by an underlying problem or a combination of factors. Excessive daytime sleepiness is defined as a difficulty staying awake or alert throughout the day. Those who experience this drowsiness often feel the urge to sleep during the day when they need to be awake . Many experts define EDS as distinct from fatigue , which involves strong feelings of physical exhaustion, but the two conditions may overlap. 

Graph showing up to 25% of Americans experience excessive daytime sleepiness. Previous studies showed lower rates of excessive daytime sleepiness in 2002 and 2012.

Recent research points to excessive sleepiness being a significant problem, affecting up to 25% of the population . Though varying definitions of excessive daytime sleepiness make it difficult to fully gauge its prevalence, it does appear to have increased in recent years .

Understanding the potential causes of excessive daytime sleepiness is an important step toward establishing a treatment plan and relieving symptoms. Excessive daytime sleepiness is not a condition in itself; instead, it is a symptom caused by an underlying problem.

Excessive Sleepiness Caused by Sleep Deprivation

Lack of sleep is widely considered to be the most common cause of excessive sleepiness . Sleep deprivation may be short-term or chronic and can have a variety of causes.

  • Failure to prioritize sleep: Sacrificing sleep for other activities can cause drowsiness the next day, and the problem can accumulate over time. When these choices cause lack of sleep over an extended period of time, it is known as insufficient sleep syndrome .
  • Poor sleep quality: Sleep insufficiency is not just about a low quantity of sleep, it is also about sleep quality. People who do not smoothly progress through sleep cycles may fail to get enough deep sleep or REM sleep. As a result, they may not wake up refreshed even if they sleep for the recommended number of hours.
  • Pain: Virtually any ailment that induces pain, including arthritis or fibromyalgia, can complicate sleep and make a person prone to drowsiness during the day.
  • Frequent nighttime urination: This condition, known as nocturia, involves needing to get up from bed during the night to use the bathroom. People who experience nocturia may find it difficult to fall back asleep after each nighttime awakening.

Excessive Sleepiness Caused by Sleep Disorders

Sleep disorders can negatively affect the amount of quality sleep a person gets, resulting in daytime drowsiness.

  • Insomnia: Insomnia makes it hard to fall asleep or stay asleep for as long as you want. Insomnia is often related to other sleep problems that give rise to excessive sleepiness.
  • Sleep apnea: Obstructive sleep apnea (OSA) is a breathing disorder characterized by brief pauses in breathing during the night. It creates fragmented sleep that typically causes daytime drowsiness. Central sleep apnea (CSA) is less common but can also cause disturbed sleep.
  • Restless legs syndrome (RLS): This condition causes a strong sensation of needing to move one’s extremities, particularly the legs. Restless legs syndrome is a known risk for disrupting total sleep time and sleep quality.
  • Circadian rhythm sleep-wake disorders: When a person’s sleep schedule is misaligned with their local day-night cycle, it can cause short and fragmented sleep. Examples include jet lag and sleep problems among shift workers.

Excessive Sleepiness Caused by Other Medical Conditions

Certain medical conditions are associated with sleep issues and excessive daytime drowsiness. 

  • Mental health disorders: It is believed that nearly 80% of people with major depression have excessive daytime sleepiness. Bipolar disorder, post-traumatic stress disorder (PTSD), and general anxiety disorder are associated with sleeping problems that may give rise to bouts of excessive sleepiness.
  • Neurological conditions: Narcolepsy is a prominent example as it is a neurological condition in which the brain cannot properly regulate the sleep-wake cycle. Narcolepsy makes people prone to falling asleep rapidly, including at inopportune times.
  • Neurodegenerative diseases: Neurodegenerative diseases including dementia and Parkinson’s disease are tied with sleeping difficulties and daytime drowsiness. 
  • Injury and infection: Traumatic brain injury (TBI) and concussions commonly cause sleeping problems , and brain tumors or lesions may provoke excessive sleepiness. Infections, including meningitis and those that cause swelling of the brain , can also lead to EDS.
  • Neurodevelopmental disorders: Attention-deficit/hyperactivity disorder (ADHD) can cause a range of sleeping problems including daytime sleepiness. Children with autism spectrum disorder (ASD) have also been found to have difficulty sleeping , which could lead to daytime sleepiness. Sleeping issues may persist into adulthood for people with these neurodevelopmental disorders.

Other health problems can make a person sleepy during the day. Metabolic problems, including diabetes and hypothyroidism, can be risk factors for drowsiness. Medical conditions like anemia, abnormal blood sodium levels, and electrolyte imbalances can also provoke excessive sleepiness.

Excessive Sleepiness Caused by Medications

A lack of sleep is not the only potential cause of excessive sleepiness. Medications, especially sedatives, can make a person drowsy and disoriented during the day. Antidepressants, pain medications, and over-the-counter antihistamines are just a few of the other types of medications that can cause sleepiness. In addition, withdrawal from some drugs may provoke drowsiness.

It is important to discuss your current medications and potential side effects with your doctor. They can offer guidance on timing and dosage of your medications and make adjustments as needed. Do not make any changes to your medication without consulting your doctor.

Getting Relief for Excessive Daytime Sleepiness (EDS)

Relief is possible for most people with excessive sleepiness. The optimal treatment for excessive sleepiness is tailored to each person based on the specific cause or contributing factors.

Because EDS can be caused by both poor sleep habits and medical and brain conditions, there are a diverse range of approaches to resolving it. A doctor is in the best position to identify and tailor optimal treatment pathways for individuals.

If drowsiness is derived from sleep deprivation, various steps can be taken to improve sleep quality and quantity. Examples include continuous positive airway pressure (CPAP) therapy for sleep apnea and cognitive behavioral therapy for insomnia (CBT-I). Many sleep-focused treatments will help facilitate improvements to sleep hygiene, which incorporates a person’s sleep habits and bedroom environment, and whether they are using the best mattress and pillow for their needs.

If EDS is tied to another medical problem, treatment typically focuses on resolving that underlying issue. Sleep hygiene improvements may be encouraged along with other treatments to help people incorporate healthy sleep tips into their daily routines.

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