Gamma-Hydroxybutyric acidgamma-Hydroxybutyric acid (or γ-hydroxybutyric acid (GHB), also known as 4-hydroxybutanoic acid) is a naturally occurring neurotransmitter and a depressant drug. It is a precursor to GABA, glutamate, and glycine in certain brain areas. It acts on the GHB receptor and is a weak agonist at the GABAB receptor. GHB has been used in the medical setting as a general anesthetic and as treatment for cataplexy, narcolepsy, and alcoholism. It is also used illegally as an intoxicant, as an athletic-performance enhancer, as a date-rape drug, and as a recreational drug.
HypothalamusThe hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is the size of an almond.
Delayed sleep phase disorderDelayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is the delaying of a person's circadian rhythm (biological clock) compared to those of societal norms. The disorder affects the timing of biological rhythms including sleep, peak period of alertness, core body temperature, and hormonal cycles. The diagnosis of this disorder is currently a point of contention among specialists of sleep disorders.
Alcohol (drug)Alcohol, sometimes referred to by the chemical name ethanol, is a depressant drug that is the active ingredient in drinks such as beer, wine, and distilled spirits (hard liquor). It is one of the oldest and most commonly consumed recreational drugs, causing the characteristic effects of alcohol intoxication ("drunkenness"). Among other effects, alcohol produces happiness and euphoria, decreased anxiety, increased sociability, sedation, impairment of cognitive, memory, motor, and sensory function, and generalized depression of central nervous system (CNS) function.
SomnolenceSomnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep, the condition of being in a drowsy state due to circadian rhythm disorders, or a symptom of other health problems. It can be accompanied by lethargy, weakness and lack of mental agility. Somnolence is often viewed as a symptom rather than a disorder by itself.
HypersomniaHypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes (such as seasonal affective disorder) and can cause distress and problems with functioning. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders. Hypersomnia is a pathological state characterized by a lack of alertness during the waking episodes of the day.
Sleep hygieneSleep hygiene is a behavioral and environmental practice developed in the late 1970s as a method to help people with mild to moderate insomnia. Clinicians assess the sleep hygiene of people with insomnia and other conditions, such as depression, and offer recommendations based on the assessment.
Shift workShift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week (often abbreviated as 24/7). The practice typically sees the day divided into shifts, set periods of time during which different groups of workers perform their duties. The term "shift work" includes both long-term night shifts and work schedules in which employees change or rotate shifts.
PolysomnographyPolysomnography (PSG), a type of sleep study, is a multi-parameter study of sleep and a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG. The name is derived from Greek and Latin roots: the Greek πολύς (polus for "many, much", indicating many channels), the Latin somnus ("sleep"), and the Greek γράφειν (graphein, "to write"). Type I polysomnography is a sleep study performed overnight while being continuously monitored by a credentialed technologist.
HypnagogiaHypnagogia is the transitional state from wakefulness to sleep, also defined as the waning state of consciousness during the onset of sleep. Its opposite state is described as hypnopompia the transitional state from sleep into wakefulness. Mental phenomena that may occur during this "threshold consciousness" phase include hypnagogic hallucinations, lucid dreaming, and sleep paralysis. The word hypnagogia is sometimes used in a restricted sense to refer to the onset of sleep, and contrasted with hypnopompia, Frederic Myers's term for waking up.