Secondary insomnia is * O treated with a CPAP machine.
O prompted by an underlying medical disorder.
O far less common than primary insomnia.
O almost always a result of stress.

prompted by an underlying medical disorder.

Explanation:

"Secondary insomnia" is due to an underlying medical disorder such as "Alzheimer's disease." This is a neurological disorder that prevents a person from having a good quality sleep due to an increase presence of amyloid in the brain.

Other medical conditions that may lead to secondary insomnia are the following: arthritis, heartburn, asthma, hot flashes, etc.