The Biological Viewpoint assumes that an abnormal behavior or viewpoint occurs as a result of something wrong with the body, and in most cases, the brain. Genetics, hormonal levels, disease, infections or a brain injury could all contribute to a person behaving differently from how they normally would.
Biologically based psychological disorders tend to appear in adulthood, and are most commonly the result of an injury to the brain which could adversely impact a persons cognitive abilities. This type of trauma could result from an external cause such as a car accident or fall, or an internal cause, such as a stroke or seizure.
Injury to the brain, either through physical trauma, disease or illness, can lead to the onset of cognitive abnormalities that may, or may not be reversible. Anterograde and retrograde amnesia are two types of mental disorders that can be attributed to a biological cause, in this case, damage to the hippocampus.
Other psychological disorders, such as schizophrenia, may occur without brain injury and could even appear unexpectedly. The cause of mental illnesses, such as schizophrenia, is not entirely known, although many medical professionals attribute its cause to genetic tendencies or illicit drug use.
Unfortunately it can be very difficult to successfully treat a person if they have something physically wrong with their brain.