"Latency to REM sleep and percentages of light sleep and REM sleep were normal, compared with normal ranges." Despite this, one study has found increased sleep fragmentation in patients with IH without long sleep time, suggesting multiple possible presentations.Per ICSD-3, five criteria must be met for a diagnosis of IH:

Daytime lapses into sleep or an irrepressible need to sleep on a daily basis, for at least 3 months
Absence of insufficient sleep syndrome
Absence of cataplexy
Absence of other causes of hypersomnia
The presence of positive MSLT tests.The latest ICD 10 defines IH with long sleep time as a neurological disorder that is a rare sleep disorder characterized by prolonged sleep at night and extreme sleepiness during the day. There are no apparent causes. This disorder affects the ability to function. It is of central nervous system origin characterized by prolonged nocturnal sleep and periods of daytime drowsiness. Affected individuals experience difficulty with awakening in the morning and may have associated sleep drunkenness, automatic behaviors, and memory disturbances. This condition differs from narcolepsy in that daytime sleep periods are longer, there is no association with cataplexy, and the multiple sleep latency onset test does not record sleep-onset rapid eye movement sleep. Management
Since the underlying mechanism is not yet fully understood, treatment efforts have usually focused on symptom management. In August 2021, low-sodium oxybate (Xywav) became the first U.S. FDA-approved treatment for idiopathic hypersomnia. Wake-promoting medications used in narcolepsy are also commonly used off-label to help manage the excessive daytime sleepiness of IH.
Acute stress disorder (ASD, also known as acute stress reaction, psychological shock, mental shock, or simply shock) is a psychological response to a terrifying, traumatic or surprising experience. It may bring about delayed stress reactions (better known as post-traumatic stress disorder, or PTSD) if not correctly addressed. Types
Sympathetic
Sympathetic acute stress disorder is caused by the release of excessive adrenaline and norepinephrine into the nervous system. These hormones may speed up a persons pulse and respiratory rate, dilate pupils, or temporarily mask pain. This type of ASD developed as an evolutionary advantage to help humans survive dangerous situations. The "fight or flight" response may allow for temporarily-enhanced physical output, even in the face of severe injury. However, other physical illnesses become more difficult to diagnose, as ASD masks the pain and other vital signs that would otherwise be symptomatic. Parasympathetic
Parasympathetic acute stress disorder is characterised by feeling faint and nauseated. This response is fairly often triggered by the sight of blood. In this stress response, the body releases acetylcholine. In many ways, this reaction is the opposite of the sympathetic response, in that it slows the heart rate and can cause the patient to either regurgitate or temporarily lose consciousness. The evolutionary value of this is unclear, although it may have allowed for prey to appear dead to avoid being eaten. Signs and symptoms
The DSM-IV specifies that acute stress disorder must be accompanied by the presence of dissociative symptoms, which largely differentiates it from post-traumatic stress disorder.