Dictionary

psychiatry The medical specialty that is concerned with the prevention, diagnosis, and treatment of mental illness.

psychiatrist A physician who specializes in the prevention, diagnosis, and treatment of mental illness. A psychiatrist must receive additional training and serve a supervised residency in his or her specialty. He or she may also have additional training in a psychiatric specialty, such as child psychiatry or neuropsychiatry. Psychiatrists can prescribe medication, which psychologists cannot…

psyche The mind.

psoriatic arthritis Joint inflammation that is associated with psoriasis. Psoriatic arthritis is a potentially destructive and deforming form of arthritis that affects approximately 10 percent of persons with psoriasis.

psoriasis, pustular An uncommon type of recurring psoriasis that is characterized by the appearance of pus-filled pimples and sores in clusters. Pustular psoriasis can be intensely painful, and hospitalization may be necessary.

psoriasis, guttate An uncommon type of psoriasis that is characterized by small, red-pink drops on the skin that are finer than the typical plaque-like rash of psoriasis. The condition may be triggered by an infection, often by Streptococcus bacteria. See psoriasis.

psoriasis A reddish, scaly, plaque-like rash that is often located over the surfaces of the elbows, knees, and scalp, and around or in the ears, navel, genitals, or buttocks. Approximately 10 to 15 percent of patients with psoriasis develop joint inflammation (inflammatory arthritis). Psoriasis is caused by the body making too many skin cells as…

psoas Two muscles of the lower back. There are two psoas muscles on each side of the back. The larger of the two is called the psoas major and the smaller the psoas minor. The psoas major originates at the spine, around the bottom of the rib cage, and runs down to the thighbone (the…

psittacosis An infectious disease that is due to a bacterium (Chlamydia psittaci) contracted from psittacine birds, especially caged birds such as parrots, parakeets, and lovebirds. It is also seen in turkey-processing plants. C. psittaci enters the human body by inhalation of air containing dried secretions from infected birds. Signs and symptoms include fever and chills,…

psilocybin An hallucinogenic compound obtained from certain mushrooms.

pseudoxanthoma elasticum A disorder that is characterized by deposition of calcium and other minerals in elastic fibers. It can affect elastic fibers in the skin, eyes, and blood vessels, and less frequently other areas. Abbreviated PXE. PXE is inherited in an autosomal recessive manner and is due to mutations in the ABCC6 gene on chromosome…

pseudotumor cerebri Increased pressure within the brain in the absence of a tumor. Pseudotumor cerebri can cause headache, ringing in the ears, double vision, loss of visual accuracy, and even complete blindness. It is most common in obese woman of childbearing age. Although its cause is usually not known, pseudotumor cerebri is sometimes linked to…