Sleep deprivation affects up to one-third of the population. Persistent insomnia, on the other hand, affects approximately 10-15% of the adult population, lowering quality of life. In older adults, the prevalence is around 25%. Insomnia is the key cause in poor mental and physical health and is a barrier to successful treatment. Insomnia has been linked to the onset of stroke, hypertension, diabetes, depression, and possibly even early mortality, according to research. According to the Diagnostic and Statistical Manual of Mental Disorders, Insomnia Disorder should be recognised and treated as needed alongside other co-morbid conditions such as depression, hypertension, cancer, or sleep apnoea.

Obstructive Sleep Apnoea (OSA) is defined by the number of apnoea and hypopnea episodes per hour of sleep, which reflects the degree of deviation from normal breathing while sleeping. Between 1988 and 1994, the prevalence of moderate-to-severe OSA was estimated to be 8.8% in males aged 30-70, but by 2007 and 2010, the prevalence had risen to 13% in males and 6% in females. This could be due to the rising prevalence of obesity and an ageing population, as well as increased awareness and diagnosis. Obesity is a risk factor for OSA, and the condition becomes more common with age. OSA affects approximately 20% of people over the age of 65, with some estimates ranging as high as 70%. The prevalence is elevated in Asian and other non-white populations. OSA is interconnected to hypertension, cardiovascular morbidity, and mortality (particularly an increased risk of stroke), sleepiness, impaired cognitive function, an increased risk of motor vehicle crashes and occupational accidents, and a lower health-related quality of life. Excess body weight and alcohol use are risk factors, smoking, nasal congestion, and menopausal change may increase the risk as well. OSA is one of the few modifiable factors that can improve quality of life in the elderly. A recent study found that treating OSA in older people not only improves daytime sleepiness but also cut costs.

Obstructive Sleep Apnoea (OSA) is defined by the number of apnoea and hypopnea episodes per hour of sleep, which reflects the degree of deviation from normal breathing while sleeping. Between 1988 and 1994, the prevalence of moderate-to-severe OSA was estimated to be 8.8% in males aged 30-70, but by 2007 and 2010, the prevalence had risen to 13% in males and 6% in females. This could be due to the rising prevalence of obesity and an ageing population, as well as increased awareness and diagnosis. Obesity is a risk factor for OSA, and the condition becomes more common with age. OSA affects approximately 20% of people over the age of 65, with some estimates ranging as high as 70%. The prevalence is elevated in Asian and other non-white populations. OSA is interconnected to hypertension, cardiovascular morbidity, and mortality (particularly an increased risk of stroke), sleepiness, impaired cognitive function, an increased risk of motor vehicle crashes and occupational accidents, and a lower health-related quality of life. Excess body weight and alcohol use are risk factors, smoking, nasal congestion, and menopausal change may increase the risk as well. OSA is one of the few modifiable factors that can improve quality of life in the elderly. A recent study found that treating OSA in older people not only improves daytime sleepiness but also cut costs.

The four common symptoms of narcolepsy are:

1. sleep attacks—sudden and irresistible desire to sleep.
2. cataplexy – is a sudden loss of muscle tone while the person is awake which is triggered by anticipatory excitement, laughter, anger, or surprise. The incidence is rare to worker
3. hypnagogic hallucinations—frightening hallucinations that occur at sleep onset
4. sleep paralysis—Often terrifying and unpleasant generalised paralysis just before or at the time of falling asleep or upon waking.

These include Shift Work Disorder and Jet Lag Disorder, as well as Advanced Sleep Phase Disorder, Delayed Sleep Phase Disorder, Free-Running Disorder, and Irregular Sleep-Wake Rhythm.

Restless legs syndrome (Willis-Ekbom disease), periodic limb movement disorder, rhythmic movement disorders, sleep-related bruxism (teeth grinding), and sleep-related leg cramps are examples of these. The prevalence of clinically significant RLS ranges from 1.5 to 3.0%. RLS is a neurological condition characterised by a strong desire to move, usually accompanied by paraesthesia (tingling or numbness), that occurs or worsens at rest, particularly in the evening and at night, and is relieved by activity. RLS symptoms have a significant impact on sleep, and patients complain of daytime fatigue and/or somnolence.

Non-REM sleep disorders, arousal parasomnias (such as sleepwalking and night terrors), and REM parasomnias (such as nightmare disorder and REM sleep behaviour disorder) are the most common types. Post-Traumatic Sleep Disorder is distinguished by recurring and distressing nightmares. The normal muscle paralysis of REM sleep is compromised in REM sleep behaviour disorder, which may be an early sign of a neurodegenerative disorder such as Parkinson's disease.