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 They include delusions of being controlled by an external force, the belief that thoughts are being inserted into or withdrawn from one's conscious mind, the belief that one's thoughts are being broadcast to other people, and hearing hallucinatory voices that comment on one's thoughts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. The absence of first-rank symptoms should raise suspicion of a medical disorder.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 Philippe Pinel 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 "praecox" 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 démence précoce in 1852 by the French physician Bénédict Morel constitutes the medical discovery of schizophrenia. 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.

Question: Are first-rank symptoms widely accepted by the scientific community?
Answer: first-rank symptoms has been questioned

Question: What should be done to first rank symptoms?
Answer: de-emphasized in future revisions of diagnostic systems.

Question: Before the 19th century, cases of schizophrenia-like symptoms were calssified as what relative to how common it was?
Answer: rare

Question: What is classified as a mood disorder?
Answer: manic depression