Webster's New World Medical Dictionary

psoriasis, guttate
An uncommon type of psoria-
sis 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, pustular
An uncommon type of
recurring psoriasis that is characterized by the
appearance of pus-filled pimples and sores in clus-
ters. Pustular psoriasis can be intensely painful, and
hospitalization may be necessary.
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.
psyche
The mind.
psychiatrist
A physician who specializes in the
prevention, diagnosis, and treatment of mental ill-
ness. A psychiatrist must receive additional training
and serve a supervised residency in his or her spe-
cialty. He or she may also have additional training in
a psychiatric specialty, such as child psychiatry or
neuropsychiatry. Psychiatrists can prescribe med-
ication, which psychologists cannot do.
psychiatry
The medical specialty that is con-
cerned with the prevention, diagnosis, and treat-
ment of mental illness.
psychogenic
Caused by the mind or emotions.
psychological child abuse
See 
child abuse.
psychological imprinting
See 
imprinting,
psychological.
psychologist
A professional who specializes in
the diagnosis and treatment of diseases of the brain,
emotional disturbance, and behavior problems.
Psychologists use talk therapy as treatment; a per-
son must see a psychiatrist or another medical doc-
tor to be treated with medication. A psychologist
may have a master’s degree (MA) or doctorate
(PhD) in psychology. Psychologists may also have
other qualifications, including board certification
and additional training in a type of therapy.
psychosis
A thought disorder in which percep-
tion of reality is grossly impaired. Symptoms can
include seeing, hearing, smelling, or tasting things
that are not there; paranoia; and delusional
thoughts. Depending on the condition underlying
the psychotic symptoms, symptoms may be constant
or they may come and go. Psychosis can occur as a
result of brain injury or disease, and it is seen par-
ticularly in schizophrenia and bipolar disorder.