Post-concussion syndrome, also known as postconcussive syndrome or PCS, and historically called shell shock, is a set of symptoms that may continue for weeks, months, or occasionally a year or more after a concussion – a mild form of traumatic brain injury (TBI). Symptoms of PCS, which is the most common entity to be diagnosed in people who have suffered TBI, may occur in 38–80% of mild head injuries. A diagnosis may be made when symptoms resulting from concussion last for more than three months after the injury, or it may be made starting within a week or ten days of trauma. In late, persistent, or prolonged PCS (PPCS), symptoms last for over six months, or by other standards, three.
The condition can cause a variety of symptoms: physical, such as headache; cognitive, such as difficulty concentrating; and emotional and behavioral, such as irritability. As many of the symptoms in PCS are common to, or exacerbated by, other disorders, there is a risk of misdiagnosis. Though there is no treatment for PCS itself, symptoms can be treated; medications and physical and behavioral therapy may be used, and patients can be educated about symptoms and their usual prognosis. The majority of PCS cases resolve after a period of time.
Science of drugs including their origin, composition, pharmacokinetics,
pharmacodynamics, therapeutic use, and toxicology.
Pharmacology (from Greek φάρμακον, pharmakon, "poison" in classic Greek; "drug" in modern Greek; and -λογία, -logia "study of", "knowledge of") is the branch of medicine and biology concerned with the study of drug action, where a drug can be broadly defined as any man-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals.