Sleep Studies for Diagnosing Sleepwalking in Adolescents: What Parents Need to Know About Testing and Nutritional Support

Story-at-a-Glance

• Sleepwalking affects approximately 9% of adolescents at some point during their youth, with about 2-3% experiencing current episodes, making proper diagnosis through sleep studies increasingly important for identifying underlying causes
• Sleep studies for diagnosing sleepwalking in adolescents—particularly polysomnography with video monitoring—reveal critical insights about sleep architecture and can distinguish sleepwalking from other conditions like nocturnal seizures
• The 2024 National Sleep Foundation poll found that nearly 80% of teens with poor sleep behaviors also experienced significant depressive symptoms, highlighting how critical proper sleep diagnosis has become for adolescent mental health
• Iron deficiency (ferritin levels below 50 ng/mL) and vitamin D insufficiency are strongly associated with sleep disorders in adolescents, including increased NREM sleep instability that can trigger parasomnia episodes
• Addressing nutritional deficiencies—particularly iron, magnesium, and vitamin D—may significantly improve sleep quality and reduce parasomnia frequency in adolescents following proper diagnosis
• A comprehensive approach combining medical diagnosis, behavioral interventions, and targeted nutritional support offers the best outcomes for adolescents with sleepwalking

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When 15-year-old Marcus started wandering into his parents’ bedroom at 2 a.m. with glazed eyes, speaking incomprehensibly before returning to his own room with no memory of the incident, his mother knew something was wrong. He had no recollection of these nighttime episodes. But was it stress from his upcoming exams? A psychological issue? Or something more complex happening during his sleep? Sleep studies for diagnosing sleepwalking in adolescents have become increasingly sophisticated. In Marcus’s case (a composite reflecting documented clinical observations), proper testing revealed not just the presence of somnambulism, but also underlying sleep-disordered breathing and nutritional deficiencies that were contributing to his nocturnal wanderings.

The teenage years represent a particularly vulnerable period for sleep disturbances. According to research published in the Philadelphia Neurodevelopmental Cohort study, the lifetime prevalence of sleepwalking is approximately 9% among youth, with current prevalence around 2.64%. What many parents don’t realize is that proper diagnosis—and the nutritional support that often follows—can dramatically improve not just the sleepwalking itself, but overall adolescent health and daytime functioning.

Understanding Why Sleep Studies Matter for Adolescent Sleepwalking

Sleepwalking, or somnambulism, isn’t simply a quirky sleep habit. It’s a parasomnia arising from non-rapid eye movement (NREM) sleep, typically during the deepest stages when the brain should be most at rest. Yet somehow, parts of the brain activate while others remain in deep sleep—creating a state where complex behaviors occur without conscious awareness or later memory.

Dr. Antonio Zadra, Professor of Psychology at the Université de Montréal and leading sleepwalking researcher at the Center for Advanced Research in Sleep Medicine, has dedicated his career to understanding this mysterious condition. His research using polysomnography and brain imaging has revealed that even when sleepwalkers aren’t actively having episodes, certain parts of their brain show unusual activity patterns during sleep. This finding suggests that sleepwalking isn’t just about individual episodes—it reflects an ongoing pattern of sleep instability that proper diagnosis can identify.

Here’s where sleep studies for diagnosing sleepwalking in adolescents become essential. Unlike younger children, adolescents face unique challenges: their circadian rhythms are naturally shifting later (making them biological night owls forced into morning-oriented school schedules), they’re experiencing dramatic hormonal changes, and they’re under increasing academic and social pressures. A recent study examining 242,948 nights of sleep data from over 17,000 young people found that sleep duration declines and sleep timing shifts dramatically throughout adolescence. The decline ranged from an average of 7 hours and 53 minutes at age 16 to just 7 hours and 29 minutes by age 30.

Additionally, the National Sleep Foundation’s 2024 Sleep in America Poll revealed something startling: nearly 80% of teens earning a “B” grade or higher for healthy sleep behaviors were free of significant depressive symptoms. Meanwhile, the typical teen received an “F” grade for sleep behaviors overall. This underscores why proper diagnosis matters—poor sleep doesn’t just cause nighttime wandering; it affects every aspect of adolescent life.

What Happens During Polysomnography for Sleepwalking

The gold standard for diagnosing sleepwalking remains overnight polysomnography (PSG) with video monitoring. But here’s an interesting challenge: sleepwalking episodes don’t always occur in the sleep lab. Adolescents may feel self-conscious in an unfamiliar environment, or the episodes themselves may be infrequent.

Research published in Neurology found an ingenious solution: sleep deprivation before polysomnography. When 30 consecutive sleepwalkers underwent both baseline sleep studies and recovery sleep after 25 hours of sleep deprivation, the frequency of somnambulistic episodes increased significantly during the post-deprivation recovery sleep. This technique has become valuable for facilitating polysomnographically-based diagnosis in predisposed adolescents.

During a sleep study, multiple measurements occur simultaneously:

• Brain activity (EEG) tracks sleep stages and can identify the characteristic “hypersynchronous slow delta waves” often seen in sleepwalkers
• Eye movements help distinguish REM from NREM sleep
• Muscle activity monitors for periodic limb movements or restless legs syndrome
• Heart rate and breathing patterns can reveal sleep-disordered breathing
• Video recording captures any movements or behaviors during sleep
• Blood oxygen levels identify potential respiratory issues

What makes this testing crucial is that it can reveal underlying conditions that precipitate sleepwalking episodes. The late Dr. Christian Guilleminault, a pioneering sleep researcher at Stanford who passed away in 2019, was among the first to describe the connection between sleep-disordered breathing and parasomnias in children. He identified that symptoms of attention deficit, hyperactivity, abnormal behavior, learning disabilities, and sleepwalking often accompanied upper airway resistance. This occurred even in non-obese children. His groundbreaking work showed that treating the underlying breathing disorder often eliminated the sleepwalking entirely.

This brings us to an essential insight: sleepwalking is often not the primary problem but rather a symptom of deeper sleep instability. And increasingly, research suggests nutritional factors play a significant role in that instability.

The Iron Connection: A Case That Changed My Perspective

Let me share a fascinating case published in Sleep that illustrates the nutritional connection to parasomnias. A 2-year-old presented with nightly sleep difficulties, restless sleep, episodes of sleepwalking, and night terrors multiple times per week. His symptoms had worsened over six months, causing daytime irritability and behavioral problems.

Polysomnography revealed no significant sleep-related breathing disorder, but showed a large muscle group movement index of 14. Blood work revealed low ferritin—just 15 ug/L (normal range for children is typically 20-200 ug/L, though symptoms can occur even at levels below 50 ug/L). The child began oral iron therapy along with scheduled awakenings and melatonin.

The results were remarkable. After one month of iron therapy, the parent reported reduction in both movements and parasomnia frequency. After three months, the parasomnia had completely ceased, restlessness drastically reduced, and insomnia nearly resolved. The ferritin level increased to 47 ug/L. Sleep quality measures showed an 11-point improvement, demonstrating reduced sleep disturbance.

While this case involved a younger child, the connection between iron status and sleep disorders in adolescents is well-established. Research in Sleep Medicine Reviews examining iron deficiency and sleep found strong associations with various sleep disorders, yet standardized assessment of iron status and supplementation have not been routinely considered in clinical practice—something that should change.

Vitamin D, Magnesium, and the Sleep Architecture Connection

Beyond iron, other nutritional factors play critical roles in adolescent sleep quality. A systematic review published in the International Journal of Environmental Research and Public Health examined vitamin D’s role in pediatric sleep disorders and found that vitamin D is implicated in neurochemical mechanisms involved in sleep regulation, particularly in serotonergic and dopaminergic pathways. Vitamin D deficiency is associated with restless sleep, sleep hyperhidrosis, obstructive sleep apnea, and restless legs syndrome.

One particularly revealing study examined children with sleep terrors—a parasomnia closely related to sleepwalking that often shares genetic predisposition. Research in Erciyes Medical Journal detected a significantly higher rate of vitamin D deficiency among children with sleep terrors compared to controls. Vitamin D receptors are located in the substantia nigra, hippocampus, and hypothalamus—areas that regulate sleep-wakefulness.

Magnesium represents another piece of the nutritional puzzle. Dr. Beth Malow, Professor of Neurology and Pediatrics at Vanderbilt University and Director of the Sleep Disorders Division, notes in her research on pediatric sleep that while melatonin is more extensively studied in children with neurodevelopmental disorders, “I’m totally open to them trying magnesium” when melatonin alone isn’t working. As reported in NPR’s coverage of sleep supplements, Dr. Malow uses magnesium in adolescent patients—not primarily as a sleep aid, but to treat migraines and tension headaches, with patients often reporting improved sleep as well.

Magnesium influences sleep through multiple mechanisms. It helps regulate GABA, the neurotransmitter that calms the nervous system, and it plays a role in melatonin production. A 2024 study in Sleep Medicine found that a melatonin-magnesium supplement improved sleep quality, sleep efficiency, latency time, total sleep time, and movement index in individuals with sleep disturbances. While the study involved adults, the mechanisms are relevant to adolescents as well.

The 2025 Wake-Up Call: Adolescent Sleep Crisis

If there was any doubt about the urgency of addressing adolescent sleep problems, the Make America Healthy Again (MAHA) Report released in 2025 put those concerns to rest. The report identified declining sleep as one of the key factors contributing to the crisis of childhood health, particularly among adolescents.

The numbers are sobering: CDC data show that 77% of high school students failed to get sufficient sleep on an average school night in 2021—and this trend has been worsening. Among younger children, 35% failed to get sufficient sleep during an average day in 2020-2021 based on parental reports.

The consequences extend far beyond tiredness. The report notes that chronic insufficient sleep impairs glucose tolerance, contributes to insulin resistance, and exacerbates mental health disorders. The sleep crisis exists within the context of a “sedentary, technology-driven lifestyle” contributing to chronic physical and mental health disease.

This makes proper diagnosis and treatment of sleep disorders like sleepwalking all the more critical. When an adolescent is experiencing parasomnia episodes, they’re not just dealing with nighttime disturbances—they’re potentially missing out on the restorative sleep essential for learning, emotional regulation, and physical health during a crucial developmental period.

Beyond Diagnosis: Practical Steps After Sleep Studies Confirm Sleepwalking

So what happens after sleep studies for diagnosing sleepwalking in adolescents confirm the diagnosis? The approach should be comprehensive, addressing both safety concerns and underlying contributors.

Immediate Safety Measures: First and foremost, sleepwalking creates injury risk. Dr. Zadra’s research has documented cases of serious injury during sleepwalking episodes. Parents need to:

• Secure windows and doors (consider locks or alarms)
• Remove sharp objects from the bedroom
• Install gates at staircases if needed
• Consider a bell on the adolescent’s door to alert parents
• Clear pathways of obstacles

Addressing Underlying Conditions: If polysomnography reveals sleep-disordered breathing, obstructive sleep apnea, or upper airway resistance syndrome, treating these conditions becomes the priority. As Dr. Guilleminault’s work demonstrated, successful treatment of breathing disorders frequently eliminates sleepwalking entirely.

Sleep Hygiene Optimization: This is absolutely foundational:

• Consistent sleep schedule (yes, even on weekends—though this battles against adolescent circadian preferences)
• Adequate sleep duration (8-10 hours recommended for teens)
• Cool, dark, quiet sleep environment
• Limiting screen time before bed (the blue light disrupts melatonin production)
• Avoiding caffeine, especially in the afternoon and evening

Nutritional Assessment and Support: Based on emerging research, I believe this deserves far more attention than it typically receives. Here’s what to consider:

Iron/Ferritin Status: Given the strong connection between low ferritin and sleep disturbances, testing ferritin levels makes sense for adolescents with sleep disorders. Be aware that standard hemoglobin tests aren’t enough—ferritin specifically needs to be measured. Levels below 50 ng/mL may contribute to sleep problems even when anemia isn’t present. Iron supplementation should be undertaken under medical supervision, as incorrect dosing can be dangerous.

Vitamin D Levels: Particularly for adolescents with limited sun exposure or darker skin tones (which require more UV exposure to synthesize vitamin D), testing vitamin D status is worthwhile. The connection between vitamin D and sleep regulation through neurotransmitter pathways suggests that optimizing vitamin D status could support better sleep architecture.

Magnesium Considerations: While testing for magnesium deficiency is challenging (serum magnesium doesn’t reliably reflect intracellular stores), dietary intake assessment can be helpful. Foods rich in magnesium include leafy greens, nuts, seeds, whole grains, and legumes. Some adolescents may benefit from supplementation, though it’s worth noting that magnesium supplements can cause digestive upset if the dose is too high.

Should you leap straight to supplements? I’d argue the answer depends on testing results and individual circumstances. If ferritin is low, addressing it makes physiological sense. If vitamin D is deficient, supplementation is appropriate. For magnesium, starting with dietary improvements and considering supplementation if symptoms persist seems reasonable—always in consultation with your healthcare provider.

When Behavioral Approaches and Pharmacotherapy Enter the Picture

Sometimes, despite optimizing sleep hygiene and addressing nutritional factors, sleep studies for diagnosing sleepwalking in adolescents reveal such frequent or dangerous episodes that additional interventions become necessary.

Cognitive behavioral therapy techniques, such as scheduled awakenings (briefly waking the adolescent 15-30 minutes before the typical sleepwalking time) can interrupt the pattern. Hypnosis and relaxation training have shown promise in some studies, though the evidence isn’t as robust as we might like.

Pharmacological treatment is generally reserved for severe cases. Benzodiazepines, particularly clonazepam, have been used, though they come with side effects and the risk of dependence. Tricyclic antidepressants and SSRIs have also been utilized. The challenge, as noted in a comprehensive review in Epilepsy & Behavior, is that there are no properly powered, rigorous controlled trials for sleepwalking treatment. Decisions must be made on limited evidence, emphasizing the importance of full discussion with patients and families.

That said—and this is where proper diagnosis proves invaluable—treating underlying conditions often eliminates the need for sleepwalking-specific medications. A study in Sleep Medicine found that chronic sleepwalkers frequently presented with sleep-disordered breathing. When treated with CPAP (continuous positive airway pressure) for their breathing disorder, compliant patients achieved complete control of sleepwalking at all stages of follow-up. Those who had successful surgical treatment for sleep-disordered breathing also experienced complete resolution of sleepwalking.

This reinforces a key principle: sleepwalking is often a symptom, not the disease itself.

A Word About What We’re Still Learning

I want to be transparent about the limitations in our current understanding. While the connections between nutritional status and sleep quality are becoming clearer, many mechanisms remain incompletely understood. The exact pathways by which magnesium influences sleep, for instance, are still being researched. The optimal vitamin D levels for sleep quality haven’t been definitively established. And individual responses to nutritional interventions vary significantly.

This is why sleep studies for diagnosing sleepwalking in adolescents remain so valuable—they provide objective data about what’s actually happening during sleep, distinguishing sleepwalking from seizures or other conditions, and revealing co-occurring issues like sleep-disordered breathing or periodic limb movements that might otherwise go undetected.

The field is evolving rapidly. Dr. Zadra’s recent work using SPECT brain imaging has revealed altered brain perfusion patterns in sleepwalkers during both sleep and wakefulness, suggesting that sleepwalking involves brain function differences that persist beyond just the episodes themselves. This points toward future diagnostic and treatment approaches we can’t yet fully envision.

Putting It All Together: A Roadmap for Parents

If your adolescent is experiencing sleepwalking episodes, here’s a practical approach:

1. Document the episodes: Keep a sleep diary noting frequency, timing, duration, and any potential triggers (late bedtime, illness, stress, etc.)
2. Ensure safety first: Implement the safety measures mentioned earlier to prevent injury while you pursue diagnosis
3. Consult with a healthcare provider: Discuss whether sleep studies for diagnosing sleepwalking in adolescents are appropriate given the frequency and nature of episodes
4. If sleep studies are recommended: Prepare your teen for what to expect—it’s an overnight stay with monitoring equipment, which can feel awkward but is generally well-tolerated
5. Review results comprehensively: Beyond confirming sleepwalking, look for underlying conditions like sleep-disordered breathing, periodic limb movements, or sleep architecture abnormalities
6. Consider nutritional assessment: Request testing for ferritin, vitamin D, and potentially other markers if not already included
7. Implement a multi-faceted approach: Address any underlying conditions identified, optimize sleep hygiene, correct nutritional deficiencies, and monitor response
8. Follow up regularly: Sleep disorders often require adjustment of interventions over time, particularly during the adolescent years when so much is changing developmentally

For those interested in supporting general health alongside professional medical care, targeted nutritional supplementation—such as high-quality vitamin C for immune support—can be part of a comprehensive wellness approach that supports overall resilience during this demanding life stage.

Looking Forward

The adolescent years are a time of dramatic change—neurologically, hormonally, socially, and emotionally. Sleep disorders during this period aren’t just inconvenient; they can have cascading effects on academic performance, mental health, physical development, and even long-term health trajectories.

What gives me hope is the growing recognition that sleep problems in adolescents deserve serious attention and comprehensive evaluation. The increasing sophistication of diagnostic tools like polysomnography, combined with emerging understanding of nutritional factors and their influence on sleep architecture, means we’re better equipped than ever to help teens like Marcus sleep safely and well.

The key is taking sleepwalking seriously enough to pursue proper diagnosis, understanding that what appears on the surface as isolated episodes of nighttime wandering may reflect deeper issues with sleep quality, breathing, nutritional status, or brain function patterns that need addressing. With proper testing, treatment of underlying conditions, and attention to the nutritional building blocks of healthy sleep, many adolescents experience dramatic improvements—not just in sleepwalking frequency, but in overall wellbeing.

If you’re navigating this with your teen, you’re not alone. Reach out to sleep specialists, ask questions, pursue testing when appropriate, and don’t underestimate the importance of addressing all contributing factors—including those we can measure in a blood test. Your adolescent’s brain is still developing, and quality sleep during this critical window matters more than most people realize.

What’s been your experience with adolescent sleep issues? Have you found particular strategies helpful? I’m always interested in hearing from parents and teens about what has worked—and what hasn’t—in managing sleep challenges during these formative years.

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FAQ

Q: What is polysomnography and how does it diagnose sleepwalking in adolescents?

A: Polysomnography, also called a sleep study, is an overnight test that monitors multiple body functions during sleep using sensors placed on the scalp, face, chest, and limbs. It measures brain activity (electroencephalography or EEG), eye movements, muscle activity, heart rate, breathing patterns, and blood oxygen levels while video cameras record any movements or behaviors. For sleepwalking diagnosis, polysomnography reveals characteristic patterns in brain wave activity during NREM (non-rapid eye movement) sleep stages 3 and 4, when sleepwalking typically occurs. The test can also identify underlying conditions that may precipitate sleepwalking episodes, such as sleep-disordered breathing, periodic limb movements, or unusual arousal patterns from deep sleep. Sometimes sleep deprivation is used before the study to increase the likelihood of capturing a sleepwalking episode, as research has shown this significantly increases episode frequency during recovery sleep.

Q: What is somnambulism?

A: Somnambulism is the medical term for sleepwalking. It’s a parasomnia (abnormal behavior during sleep) that occurs during NREM sleep, typically during the deepest sleep stages in the first third of the night. During somnambulism, parts of the brain associated with motor activity become active while other areas remain in deep sleep, resulting in complex behaviors performed without conscious awareness. People experiencing somnambulism can perform activities ranging from simple (sitting up in bed, walking around a room) to complex (getting dressed, rearranging furniture, or even leaving the house). They typically have slow speech, severely diminished awareness, blunted responses to others, and partial or complete amnesia for the episode afterward. Somnambulism affects approximately 9% of youth at some point during childhood and adolescence, with a current prevalence of about 2-3%.

Q: What is ferritin and why does it matter for sleep?

A: Ferritin is a protein that stores iron in the body, and serum ferritin levels in blood tests indicate how much iron is in reserve. Iron is essential for many brain functions, including the synthesis of neurotransmitters like dopamine that regulate sleep-wake cycles and motor control. Low ferritin levels (particularly below 50 ng/mL) are associated with sleep-related movement disorders, restless sleep, and parasomnias in children and adolescents. Iron deficiency in the brain leads to alterations in dopaminergic pathways and increased sleep instability, particularly affecting NREM (non-rapid eye movement) sleep where sleepwalking occurs. Importantly, ferritin can be low even when standard hemoglobin tests are normal, which is why specific ferritin testing is important when evaluating sleep disorders. Research has shown that iron supplementation in adolescents with low ferritin and sleep disturbances can significantly improve sleep quality and reduce parasomnia frequency, though supplementation should always be done under medical supervision.

Q: What is NREM sleep?

A: NREM stands for non-rapid eye movement sleep, which comprises about 75-80% of total sleep time and consists of three stages (N1, N2, and N3). N1 is the lightest stage when you’re just drifting off, N2 is a deeper sleep where heart rate slows and body temperature drops, and N3 is the deepest sleep stage (also called slow-wave sleep) when the body repairs tissues, builds bone and muscle, and strengthens the immune system. The brain shows characteristic slow delta waves during N3 sleep on EEG monitoring. Sleepwalking and other parasomnias like night terrors arise from N3 sleep, typically in the first third of the night when deep sleep is most abundant. During these episodes, parts of the brain associated with movement and basic functions activate while areas responsible for consciousness and memory remain in deep sleep. This creates the unusual state where complex behaviors can occur without awareness or later memory. NREM sleep is particularly important for memory consolidation and physical restoration, which is why disorders affecting NREM sleep quality can have significant impacts on daytime functioning, especially in adolescents whose brains are still developing.

Q: Can nutritional supplements replace medical diagnosis and treatment for sleepwalking?

A: No, nutritional supplements cannot and should not replace proper medical evaluation, diagnosis, and treatment for sleepwalking in adolescents. Sleep studies performed by qualified sleep specialists are essential to accurately diagnose sleepwalking, rule out other conditions like nocturnal seizures, and identify potentially serious underlying problems such as sleep-disordered breathing that require specific medical treatment. However, after proper diagnosis, addressing nutritional deficiencies (particularly iron, vitamin D, and magnesium) may be an important component of a comprehensive treatment approach. Research shows that correcting low ferritin levels, optimizing vitamin D status, and ensuring adequate magnesium can improve sleep quality and reduce parasomnia frequency in many cases. Think of nutritional support as one piece of the puzzle—alongside proper medical care, safety measures, sleep hygiene, and treatment of underlying conditions—rather than a standalone solution. Always work with healthcare providers to determine if testing for nutritional deficiencies is appropriate and to oversee any supplementation, as incorrect dosing (especially of iron) can be harmful.

Q: What is the AHI mentioned in sleep studies?

A: AHI stands for Apnea-Hypopnea Index, a measurement used in sleep studies to diagnose and assess the severity of sleep apnea. It represents the number of apneas (complete pauses in breathing lasting at least 10 seconds) plus hypopneas (partial reductions in breathing) per hour of sleep. An AHI of less than 5 is considered normal, 5-15 is mild sleep apnea, 15-30 is moderate sleep apnea, and over 30 is severe sleep apnea. The AHI is important for sleepwalking evaluation because sleep-disordered breathing (including obstructive sleep apnea and upper airway resistance syndrome) is a common underlying trigger for parasomnia episodes in adolescents. Dr. Christian Guilleminault and Dr. William Dement at Stanford developed the AHI measurement system, which is still used today to characterize sleep apnea. Research has shown that treating sleep-disordered breathing with CPAP (continuous positive airway pressure) or other interventions often eliminates sleepwalking completely, which is why measuring the AHI during sleep studies is crucial for identifying treatable underlying causes of parasomnias.

Q: What is GABA and how does it relate to sleep and magnesium?

A: GABA (gamma-aminobutyric acid) is the brain’s primary inhibitory neurotransmitter, meaning it reduces nerve cell excitability and has a calming effect on the nervous system. GABA essentially “turns off” wakefulness signals in the brain, helping you transition from alertness to sleep and maintaining sleep throughout the night. Magnesium plays a crucial role in regulating GABA function—it helps activate GABA receptors and may influence GABA synthesis. This is one of the key mechanisms by which magnesium affects sleep quality: by supporting GABA activity, magnesium promotes nervous system relaxation and helps facilitate the transition into and maintenance of sleep. Research suggests that magnesium also helps regulate other sleep-related neurotransmitters and receptors, including blocking the excitatory NMDA receptors that can interfere with sleep when overactive. This multi-faceted action on the nervous system is why magnesium supplementation has been studied for improving sleep quality, reducing sleep latency (time to fall asleep), and decreasing nighttime awakenings, though more research is needed to fully understand optimal dosing and effectiveness, particularly in adolescent populations.

Q: How common is vitamin D deficiency in adolescents?

A: Vitamin D deficiency and insufficiency are remarkably common in adolescents worldwide, affecting a substantial portion of this age group despite the important roles vitamin D plays in bone health, immune function, and neurological processes including sleep regulation. Studies have found vitamin D insufficiency rates ranging from 40% to over 70% in various adolescent populations, depending on factors like geographic location, season, skin pigmentation, time spent outdoors, dietary intake, and cultural practices around sun exposure and clothing. Adolescents are particularly vulnerable to vitamin D deficiency because of lifestyle factors common during these years: reduced outdoor activity time, increased screen time indoors, dietary habits that may not include vitamin D-rich foods (fatty fish, fortified dairy), and in some cases cultural or religious practices that limit sun exposure. The prevalence tends to be higher among adolescents with darker skin tones (which require more UV exposure to synthesize equivalent amounts of vitamin D), those living at higher latitudes with less intense sunlight, and those spending most daylight hours indoors. The connection between vitamin D status and sleep disorders is receiving increased attention, as vitamin D receptors are found in brain regions regulating the sleep-wake cycle, and vitamin D influences neurotransmitter synthesis pathways involved in sleep regulation.