Sleep Disorders

Occasional difficulty sleeping is common, but when does it become a disorder? Sleep Disorders, like insomnia, are characterised by poor sleep that is consistent, typically occurring at least 3 times a week for 3 months or more. This, in turn, negatively affects daily functioning, mood, concentration and overall health. 

Sleep disorders could also indicate underlying medical or psychological conditions that may need professional assessment and treatment — from therapy to pharmacological interventions.

What are sleep disorders?

Sleep disorders are conditions that affect your sleep quality, amount, and pattern. These conditions are typically categorised based on the symptoms and how it affects you.

Types of sleep disorders

The International Classification of Sleep Disorders categorise the different types of sleep disorders as follows [1]:

• Insomnia – Insomnia refers to sleep disorders characterised by difficulty falling and staying asleep, resulting in daytime consequences such as fatigue, irritable mood, and reduced productivity. Insomnia includes chronic insomnia and short-term insomnia.
  
• Sleep-disordered breathing – Sleep-disordered breathing encompasses breathing disorders that occur when you sleep, these include obstructive sleep apnea (OSA), central sleep apnea syndromes, sleep-related hypoventilation disorders, and sleep-related hypoxaemia disorders.
  
• Central disorders of hypersomnolence – Central disorders of hypersomnolence are characterised by excessive daytime sleepiness which are not caused by other sleep disorders especially those that cause disturbance in sleep cycles or patterns. Common examples are narcolepsy, idiopathic hypersomnia, and Kleine-Levin syndrome.
  
• Circadian rhythm sleep-wake disorders – Variations in your ‘internal clock’ or circadian cycle makes it difficult to fall asleep and wake up normally. Circadian rhythm disorders are attributed to environmental and internal factors. Environmental influences can include jetlags or working the night shift, while internal factors can include delayed sleep phase syndrome, advance sleep phase syndrome, and non-24-h sleep-wake rhythm disorder.
  
• Parasomnias – Parasomnias refer to abnormal movement and behaviours while asleep. Parasomnias are further categorised to non-rapid eye movement (NREM) related, such as sleepwalking, sleep terrors, and sleep-related eating disorder, and rapid eye movement (REM) related, such as sleep paralysis, REM sleep behaviour disorder, and nightmare disorder.
  
• Sleep-related movement disorders – Sleep-related movement disorders involve movements that lead to waking up and difficulty staying asleep. Common examples are restless leg syndrome, periodic limb movement disorder, sleep-related leg cramps, and sleep-related bruxism.
  

What are the symptoms of sleep disorders?

Symptoms of sleep disorders vary depending on the type of sleep disorder. Common symptoms of sleep disorder include: 

• Difficulty falling asleep
• Difficulty staying asleep
• Snoring or choking while asleep
• Having the urge to move when you are resting, lying down, or trying to sleep
• Inability to move when you wake up

Most sleep disorders are also accompanied by daytime consequences:

• Daytime sleepiness
• Mood changes, such as irritability, short temper, or being unable to control your emotions
• Problems with focus
• Fatigue 
• Low productivity

What causes sleep disorders?

Causes and pathophysiology of sleep disorders can vary among disorders as well. Most disorders also have unclear causes and mechanisms [2].

• Insomnia – Behavioural, cognitive, emotional, and genetics factors are thought to play a role in insomnia. Insomnia can also be a result of other underlying conditions, such as psychiatric disorders, breathing problems, reflux disease, and even stress [3]. Sometimes, insomnia can also be caused by substance abuse and use of medications.
  
• Sleep-disordered breathing – Sleep-related breathing disorders, such as sleep apnea, typically stem from a stop in airflow in the upper respiratory tract. In OSA, the upper airway collapses, causing the cessation of airflow. In central sleep apnea, airflow is interrupted due to interrupted signals from the brain that controls the muscles during breathing [2]. Obesity can be a contributing risk factor in sleep-disordered breathing [4].
  
• Central disorders of hypersomnolence – Disorders characterised by excessive daytime sleepiness are typically caused by central nervous system abnormalities that control the sleep-wake cycle, and not as a result of other sleep disorders that cause disturbed sleep. Hence, patients with central disorders of hypersomnolence are not considered sleep-deprived.
  
• Circadian rhythm sleep-wake disorders – Circadian rhythm sleep-wake disorders can be caused by intrinsic sleep-wake cycles, and influences from external environmental factors. Often irregularities in the internal circadian cycles which do not match with the typical 24h cycle. For example, patients with advanced sleep phase disorder may have an internal circadian cycle less than 24h, while patients with delayed sleep phase disorder may have a circadian cycle that exceeds 24h [5].
  
• Parasomnias – Parasomnia refers to a group of sleep disorders that involve abnormal behaviours, movements, emotions or perceptions during specific stages of sleep. The exact cause of parasomnia disorders are not clearly understood, but is believed to be a result of environmental and genetic interactions [1]. 

NREM disorders are thought to be caused by disturbances to stage 3 of the sleep cycle, also known as slow wave sleep. REM disorders are thought to be associated with neurodegenerative conditions with low dopamine activity, post-traumatic stress disorder, and narcolepsy. Scientists are still studying the relationship between these conditions and parasomnia disorders [6].

• Sleep-related movement disorders – A common sleep-related movement disorder is restless leg syndrome (RLS). RLS can be idiopathic, with unknown causes, or secondary, which can be linked to neurological disorders (multiple sclerosis, Parkinson’s disease), iron deficiency, or pregnancy [2]. Genetic factors may also play a role in the causes of RLS [1].

What are the risks and complications of sleep disorders?

Our body recovers most during sleep. Hence, untreated and chronic sleep disorders can lead to diminished function, poor quality of life, and may even be life-threatening. Common complications of sleep disorders include:

• Difficulty focusing on tasks, leading to poor performance
• Fatigue and low energy
• Negative mood, irritability
• Slower reaction time
• Vehicular accidents
• Falls
• Depression
• Hypertension
• Heart diseases
• Dementia
• Type 2 diabetes
• Obesity

Lack of sleep may contribute to dysregulation of hormones relating to satiety and insulin sensitivity, which may increase the risk of obesity and type 2 diabetes due increased appetite and poor appetite control [7, 8].

How are sleep disorders diagnosed?

Symptoms of sleep disorders vary among disorders, and diagnosis can often be done by symptom assessment alone [4]. Certain specific tests can be done to confirm the diagnosis and examine your brain activity during sleep.

• Physical examination – Physical examination typically involves taking your symptoms, medical, and family history. Your doctor may perform some tests to learn more about your symptoms, such as Epworth sleepiness scale (ESS), Fatigue severity scale (FSS), Insomnia Severity Index (ISI) [1]. Blood tests and lumbar puncture may be necessary to identify or rule out other underlying conditions that may contribute to your sleep disorder.
  
• Sleep log – Sleep logs are personal records of sleep over a period of weeks to months. You should record details of your sleep including bedtime, duration of sleep, how many times you are woken up at night, how long it took to fall asleep, nap times, and other important details. Actigraphy watches or devices may also be useful to log your sleep patterns.
  
• Polysomnography – Polysomnography monitors your brain activity, eye movements, muscle activity, heart rate, and respiratory rate while asleep. Measuring brain activity allows the doctor to assess sleep stages, sleep latency, and arousal. Eye movements are useful in assessing REM sleep, muscle activity is used to look for signs of sleep-related movement disorders or parasomnias. Heart rate and respiratory rate measurements are beneficial for the diagnosis of breathing disorders [4].
  
• Multiple sleep latency test (MSLT) – MSLT are typically used in the diagnosis of hypersomnia disorders, the test involves your doctor monitoring you during 5 scheduled naps throughout the test duration via sensors that track your brain activity and eye movements. Each nap is spaced between a 2-hour break.

How are sleep disorders treated?

Treatment of sleep disorders range from lifestyle adjustments to pharmacological treatments, these can include [1, 4]:

• Sleep routine adjustments – Having a routine before bedtime can help regulate your sleep cycle and pattern. This may include having a relaxing routine before bed, avoiding using electronics in bed, and going to bed at the same time every night.
  
• Lifestyle adjustments – Lifestyle adjustments such as reducing caffeine, alcohol, and nicotine intake, avoiding exercise too late in the evening can help improve your sleep schedule.
  
• Cognitive behavioural therapy – Cognitive behaviour therapy is commonly indicated for insomnia, and is typically recommended for patients who may not be able to take medications for insomnia such as elderly patients, or patients at risk of addiction.
  
• Benzodiazepines – Benzodiazepines such as estazolam, flurazepam, quazepam, and triazolam induce sedation by slowing down brain activity. Benzodiazepines can be used to treat insomnia and to induce sleep.
  
• Hypnotics – Commonly known as Z drugs, or benzodiazepine receptor agonists, these drugs also induce sedation and sleep in insomnia patients. Common examples are zolpidem and zaleplon.
  
• Melatonin receptor agonists – Melatonin receptors are involved in regulating the sleep-wake cycle, melatonin and melatonin receptor agonists such as ramelteon can be used in insomnia patients and circadian rhythm sleep-wake disorder patients.
  
• Orexin receptor antagonists – Orexin is a neuropeptide produced in the brain that promotes arousal, wakefulness, and appetite, orexin receptor antagonists such as suvorexant and lemborexant can suppress wakefulness and promote sleep.
  
• Antidepressants – Antidepressants such as mirtazapine, trazodone, amitriptyline, or selective serotonin uptake inhibitors (SSRIs) are used in the treatment of different sleep disorders including insomnia, hypersomnia and narcolepsy, and parasomnia disorders [2].
  
• Continuous positive airway pressure (CPAP) – A CPAP machine is typically used to treat OSA and central sleep apnea patients. The device is worn while sleeping to allow uninterrupted airflow while asleep.
  
• Stimulants – Stimulants such as modafinil, armodafinil, and methylphenidate are typically used to treat narcolepsy and daytime sleepiness.
  
• Light therapy – Light-phase shift therapy involves exposure to bright lights to induce or adjust the patient’s abnormal circadian rhythm or cycle.
  
• Gabapentin enacarbil – Gabapentin enacarbil is a type of anticonvulsant medication given to patients experiencing RLS.
  
• Dopamine agonists – Dopamine agonists such as levodopa, ropinirole, and pramipexole are also commonly used to treat RLS [2].

Summary

Our body undergoes critical restorative processes during sleep. However, they are often overlooked as a neurological disorder. Left untreated, they can negatively affect your ability to perform in your daily tasks, lower general well-being, and, in severe cases, may also lead to life-threatening scenarios, such as vehicular collisions and falls. 

Thankfully, effective treatments for sleep disorders are available to improve your symptoms, quality of life — improving both physical, and mental health. 

If you experience problems with your sleep, schedule a consultation with us for a comprehensive diagnosis and personalised treatment plan. 

Frequently Asked Questions

How can I prevent sleep disorders?

Maintaining healthy sleep habits can prevent sleep disorders, this includes having a regular sleep schedule, avoiding stimulus before bed, and keeping your surroundings conducive for uninterrupted sleep (e.g. quiet, dark, cool bedroom). If you still experience sleep disorders even with these habits put in place, in which case a visit to your healthcare provider is highly recommended.

When should I see a doctor for sleep disorders?

You should visit your doctor for sleep disorders when they affect the quality and amount of sleep you are getting, these can consequently affect your ability to perform basic tasks, affect your mood, or can potentially put you in dangerous situations. Sometimes, your loved ones may notice symptoms you might not know, such as loud snoring or sleepwalking.

How much sleep do I need?

The amount of sleep you need may vary from others, generally sleep requirements vary with age:

• Babies – About 14 hours
• Children – 9 to 12 hours
• Adolescents – 8 to 10 hours
• Adult – 7 to 9 hours
• Elderly – 7 to 8 hours

However, individual variations may exist and it is important to listen to what your body needs and consult your healthcare provider.

Does lack of sleep lower life expectancy?

Some studies suggest that lack of sleep can lead to a lower life expectancy, the lack of sleep can have detrimental effects on metabolic, endocrine, and immune functions. However, new studies have suggested that sleep regularity has a more significant impact on life expectancy than sleep duration [9, 10]. Hence, it is important to maintain a regular sleep schedule and healthy sleep habits.

How does a Neurologist help with sleep disorders?

Neurologists specialise in issues regarding the brain and nervous system, both of which play a crucial role in regulating sleep. They can diagnose and treat sleep disorders, such as insomnia, sleep apnea or restless leg syndrome. 

Can sleep disorders go away on their own?

Mild sleep disorders may resolve on their own. However chronic sleep disorders, such as insomnia, obstructive sleep apnea, or restless leg syndrome, typically do not go away on their own and worsen over time without treatment. This makes an early diagnosis and the right treatment crucial to improving your symptoms. Sleeping difficulties that do not resolve within a few weeks or start interfering with your day-to-day life, requires professional medical help. 

References

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3. Kaur H, Spurling BC, Bollu PC. Chronic Insomnia. 2023 Jul 10. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. PMID: 30252392.
4. Holder S, Narula NS. Common Sleep Disorders in Adults: Diagnosis and Management. Am Fam Physician. 2022 Apr 1;105(4):397-405. PMID: 35426627.
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6. Fariba KA, Tadi P. Parasomnias. 2023 Jul 17. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. PMID: 32809359.
7. Knutson KL, Van Cauter E. Associations between sleep loss and increased risk of obesity and diabetes. Ann N Y Acad Sci. 2008;1129:287-304. doi: 10.1196/annals.1417.033. PMID: 18591489; PMCID: PMC4394987.
8. Darraj A. The Link Between Sleeping and Type 2 Diabetes: A Systematic Review. Cureus. 2023 Nov 3;15(11):e48228. doi: 10.7759/cureus.48228. PMID: 38050514; PMCID: PMC10693913.
9. Windred DP, Burns AC, Lane JM, Saxena R, Rutter MK, Cain SW, Phillips AJK. Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study. Sleep. 2024 Jan 11;47(1):zsad253. doi: 10.1093/sleep/zsad253. PMID: 37738616; PMCID: PMC10782501.
10. Cappuccio FP, D'Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010 May;33(5):585-92. doi: 10.1093/sleep/33.5.585. PMID: 20469800; PMCID: PMC2864873.