Insomnia Types and Definitions

The word Insomnia comes from Latin, the Roman God of Sleep, Somnus. (Hypnos to the Greeks) But what is Insomnia? The National Institute of Health defines insomnia as "a common condition in which you have trouble falling or staying asleep. This condition can range from mild to severe, depending on how often it occurs and for how long."
NIH (National Institute of Health) categorizes Insomnia into chronic (ongoing) or acute (short-term). With chronic insomnia symptoms persist at least 3 nights a week for more than a month. Acute insomnia lasts for less time.

NIH also points out that some insomnia sufferers have trouble falling asleep while others have a hard time staying asleep. In either case the quality of sleep is diminished, which leads to drowsiness and fatigue.

Although NIH categorized chronic and acute insomnia, they identify two types of insomnia.
The most common type is called secondary or comorbid insomnia. More than 8 out of 10 people who have insomnia are believed to have secondary insomnia. This type of insomnia is a symptom or side effect of some other problem. Certain medical conditions, medicines, sleep disorders, and substances can cause secondary insomnia.

In contrast, NIH says, primary insomnia isn't due to a medical problem, medicines, or other substances. It is its own disorder. A number of life changes can trigger primary insomnia, including long-lasting stress and emotional upset.

NIH seems to be saying that all Insomnia is caused by something else.

Insomnia can lead to excessive drowsiness, depression, increased blood pressure and could cause accidents.

NIH advises that secondary insomnia often resolves or improves without treatment if you can stop its cause—especially if you can correct the problem soon after it starts. Causes include caffeine, limiting your intake may cause your insomnia to go away.

Lifestyle changes, including better sleep habits, often help relieve acute insomnia.

NIH also recommends for chronic insomnia, your doctor may recommend a type of counseling called cognitive-behavioral therapy or medicines.