Schizophrenia, formerly dementia precox, characterized by the breakdown of thinking processes and emotional reactions. Schizophrenic disorders, in general, are characterized by characteristic fundamental disorders of thinking and perception, as well as inadequate or reduced affect. The most common manifestations of the disease are auditory pseudohallucinations, confabulations, paranoid or fantastic delusions, or disorganization of speech and thinking against the background of significant social dysfunction and impaired performance.

The variety of symptoms has given rise to a debate about whether schizophrenia is a single disease or is a diagnosis that hides a number of separate syndromes. This ambiguity was reflected in the choice of the name: Bleiler used the plural, referring to the disease as schizophrenia.

The etymology of the word, from "splitting of the mind", causes confusion — in popular culture, the disease is confused with "split personality" — an inaccurate name for dissociative identity disorder. The first known erroneous use of the term was noted in an article by the poet T. S. Eliot, published in 1933.

The overall risk of the disease, according to research, is. Men and women get sick about equally often, but women tend to have a later onset of the disease.