Eight hours of sleep per night is recommended by physicians to ensure proper mental and physical health. Most people do not get the complete eight hours due to various reasons, such as stress, anxiety, work pressure and, more seriously, sleep disorders. In clinical terms, an irregular pattern of sleep due to difficulty in falling asleep at night is a sleep disorder. This causes sleepiness at inappropriate locations and times, such as at work or while driving. Irritation, snappy behavior, and mistakes in work are some side effects of sleep disorders.

Research has identified over 100 varieties of sleep disorders, each with a different cause.

The most common types are insomnia, sleep apnea, narcolepsy and restless leg syndrome.

Insomnia denotes a mix of trouble with falling asleep, an inability to sleep once disturbed, or waking up early in the morning. Causes include anxiety, improper sleeping arrangements, smoking, substance abuse, stress, excessive sleeping during daytime, medical conditions, and so on. All of this results in lower energy level, fatigue, and dark circles around the eyes.

Sleep apnea occurs when the throat muscles relax to the extent of causing breathing to slop. This results in loud snoring and improper breathing. This can lead to heart failure.

Narcolepsy affects both sexes. It refers to drowsiness in the daytime that causes uncontrollable sleeping. Some persons experience hallucinations during this state.

Restless leg syndrome denotes a sensation in the lower legs that causes discomfort. People feel relieved when they move their legs. Continuous leg movements make the person unable to sleep well.

Sleepwalking and constant nightmares are also kinds of sleep disorders. These need to be treated accordingly.

Diagnosing sleep disorders is based on symptoms mentioned by patients, a family history of sleep disorders, observations and tests such as Epworth sleepiness scale, Nocturnal Polysomnogram, Multiple Sleep Latency Test and the Repeated Test Of Sustained Wakefulness.