The history of Schizophrenia is complex and does not lend itself easily to a linear narrative. Accounts of a Schizophrenia-like syndrome are thought to be rare in historical records before the 19th century, although reports of irrational, unintelligible, or uncontrolled behavior were common. A detailed case report in 1797 concerning James Tilly Matthews, and accounts by PhillipePinel published in 1809, are often regarded as the earliest cases of the illness in the medical and psychiatric literature.

 
 

The Latinized term dementia praecox was first used by German alienist Heinrich Schule in 1886 and then in 1891 by Arnold Pick in a case report of a psychotic disorder (hebephrenia). In 1893 Emil Kraepelin borrowed the term from Schule and Pick and in 1899 introduced a broad new distinction in the classification of mental disorders between dementia praecox and mood disorder (termed manic depression and including both unipolar and bipolar depression).

 

Kraepelin believed that dementia praecox was probably caused by a long-term, smouldering systemic or "whole body" disease process that affected many organs and peripheral nerves in the body but which affected the brain after puberty in a final decisive cascade. His use of the term dementia distinguished it from other forms of dementia such as Alzheimer's disease which typically occur later in life. It is sometimes argued that the use of the term démenceprécoce in 1852 by the French physician Bénédict Morel constitutes the medical discovery of Schizophrenia. However this account ignores the fact that there is little to connect Morel's descriptive use of the term and the independent development of the dementia praecox disease concept at the end of the nineteenth-century. Molecule of chlorpromazine (trade name Thorazine), which revolutionized treatment of Schizophrenia in the 1950s

 

The word Schizophrenia—which translates roughly as "splitting of the mind" and comes from the Greek roots schizein (σχίζειν, "to split") and phrēn, phren- (φρήν, φρεν-, "mind")—was coined by EugenBleuler in 1908 and was intended to describe the separation of function between personality, thinking, memory, and perception. American and British interpretations of Beuler led to the claim that he described its main symptoms as 4 A's: flattened Affect, Autism, and impaired Association of ideas and Ambivalence. Bleuler realized that the illness was not a dementia, as some of his patients improved rather than deteriorated, and thus proposed the term Schizophrenia instead. Treatment was revolutionized in the mid-1950s with the development and introduction of chlorpromazine.

 

The term Schizophrenia is commonly misunderstood to mean that affected persons have a "split personality". Although some people diagnosed with Schizophrenia may hear voices and may experience the voices as distinct personalities, Schizophrenia does not involve a person changing among distinct multiple personalities. The confusion arises in part due to the literal interpretation of Bleuler's term Schizophrenia (Bleuler originally associated Schizophrenia with dissociation and included split personality in his category of Schizophrenia).

 

Both Bleuler and Kraepelin subdivided Schizophrenia into categories, based on prominent symptoms and prognoses. Over the years, those working in this field have continued to attempt to classify types of Schizophrenia. Five types were delineated in the DSM-III: disorganized, catatonic, paranoid, residual, and undifferentiated. The first three categories were originally proposed by Kraepelin. These classifications, while still employed in DSM-IV, have not shown to be helpful in predicting outcome of the disorder, and the types are not reliably diagnosed. Many researchers are using other systems to classify types of the disorder, based on the preponderance of "positive" vs "negative" symptoms (see symptoms of Schizophrenia above), the progression of the disorder in terms of type and severity of symptoms over time, and the co-occurrence of other mental disorders and syndromes. It is hoped that differentiating types of Schizophrenia based on clinical symptoms will help to determine different etiologies or causes of the disorder.

In the early 20th century, the psychiatrist Kurt Schneider listed the forms of psychotic symptoms that he thought distinguished Schizophrenia from other psychotic disorders. These are called first-rank symptoms or Schneider's first-rank symptoms. They include delusions of being controlled by an external force; the belief that thoughts are being inserted into or withdrawn from one's conscious mind; the belief that one's thoughts are being broadcast to other people; and hearing hallucinatory voices that comment on one's thoughts or actions or that have a conversation with other hallucinated voices. Although they have significantly contributed to the current diagnostic criteria, the specificity of first-rank symptoms has been questioned. A review of the diagnostic studies conducted between 1970 and 2005 found that they allow neither a reconfirmation nor a rejection of Schneider's claims, and suggested that first-rank symptoms should be de-emphasized in future revisions of diagnostic systems.

In the early 1970s, the diagnostic criteria for Schizophrenia were the subject of a number of controversies which eventually led to the operational criteria used today. It became clear after the 1971 US-UK Diagnostic Study that Schizophrenia was diagnosed to a far greater extent in America than in Europe. This was partly due to looser diagnostic criteria in the US, which used the DSM-II manual, contrasting with Europe and its ICD-9. David
 

Rosenhan's 1972 study, published in the journal Science under the title "On being sane in insane places", concluded that the diagnosis of Schizophrenia in the US was often subjective and unreliable. These were some of the factors leading to the revision not only of the diagnosis of Schizophrenia, but the revision of the whole DSM manual, resulting in the publication of the DSM-III in 1980.

Dissociative identity disorder (having a "split personality") was also often misdiagnosed as Schizophrenia based on the loose criteria in the DSM-II. The first known misuse of the term to mean "split personality" was in an article by the poet T. S. Eliot in 1933. Other scholars have traced earlier roots.

Mental illness has been recognized for thousands of years. At one point, all people who were considered "abnormal," whether due to mental illness, mental retardation, or physical deformities, were largely treated the same. Early theories supposed that mental disorders were caused by evil possession of the body, and the appropriate treatment was then exorcising these demons, through various means, ranging from innocuous treatments, such as exposing the patient to certain types of music, to dangerous and sometimes deadly means, such as releasing the evil spirits by drilling holes in the patient's skull.

One of the first to classify the mental disorders into different categories was the German physician, Emil Kraepelin. He used the term "dementia praecox" for individuals who had symptoms that we now associate with Schizophrenia. The classifications for mental disorders continue to be revised. The most recent diagnostic classification system that is most commonly used in the United States is the Diagnostic and Statistical Manual for Mental Disorders - Fourth Edition (DSM-IV).
In 2002 the term for Schizophrenia in Japan was changed from Seishin-Bunretsu-By ō精神分裂病 (mind-split-disease) to Tōgō-shitchō-shō統合失調症 (integration disorder) to reduce stigma. The new name was inspired by the biopsychosocial model; it increased the percentage of patients who were informed of the diagnosis from 37% to 70% over three years.
 

In the United States, the cost of Schizophrenia—including direct costs (outpatient, inpatient, drugs, and long-term care) and non-health care costs (law enforcement, reduced workplace productivity, and unemployment)—was estimated to be $62.7 billion in 2002.The book and film A Beautiful Mind chronicles the life of John Forbes Nash, a Nobel Prize-winning mathematician who was diagnosed with Schizophrenia.