Schizophrenia is a disease of the brain that eludes simple definition. Despite evidence indicating that a chemical imbalance in the brain is at the root of the disease, the illness is most often defined as a collection of symptoms, some of which vary among individuals and within those same persons over the course of their lives. Current research investigating unstable DNA may shed some light on the cause of the disease. Reality distortion can evoke hallucinations or delusions, and can interfere with the ability to attend school or hold down a job. Depression and suicide often result from the frustration of trying to cope, and some who have the disease may be dangerous to others.
Schizophrenia is caused principally by biological factors, most of which reside in the brain.
As such, the illness should be though of as a disease in the same sense as cancer and heart disease are considered. Symptoms of schizophrenia may be categorized as positive or negative. Positive refers to something being added to existing behaviour or perception, such as a hallucination. Negative refers to something missing, such as lack of appropriate affect, or social interaction. The cure for schizophrenia will be found in the neurosciences.