Primary<unk>  is sleeplessness that is not attributable to a medical or environmental cause. Secondary<unk>  means that a person is having sleep problems because of something else, such as a health condition, an example of which would be generalized anxiety disorder.
Insomnia etiology
Altered mental status pathophysiology
Delirium laboratory findings
Syncope pathophysiology
Sleep debt
Clinical depression
Delirium risk factors
Disordered eating