Abstract: Short peptides are provided, which bind to a body fluid sample obtained from a schizophrenic patient at a substantively higher level than to a body fluid sample obtained from a non-schizophrenic individual. The peptides are no more than 10 amino acids long and comprise a continuous sequence of at least 5 amino acids which consists of at least one positively charged amino acid at one of its ends. The provided peptides, which are the putative binding sites of autoantibodies found in high levels in schizophrenic individuals, are thus useful in diagnosis of schizophrenia.

Abstract: The invention concerns peptides which bind antibodies that are found in elevated levels in body fluids of schizophrenic patients and are found at a lower level or not found at all in body fluids of non-schizophrenic individuals. Using a computerized program, the antigenic epitope of the peptides of the invention is predicted as having a core of hydrophobic amino acids which is surrounded by positively charged amino acids. The peptides of the invention are useful in the diagnosis of schizophrenia in an individual.

Abstract: A diagnostic method for assaying schizophrenia in a subject is provided wherein a preparation comprising platelet derived proteins or fractions thereof having a pI above about 6.5 is injected into a subject and the occurrence of delayed type hypersensitivity (DTH) reaction at the site of the injection is determined. A positive DTH reaction indicates that the tested subject has a high likelihood of being schizophrenic. The protein preparation used in the diagnostic method is also provided as well as a method for its preparation and a kit for use in the diagnosis of schizophrenia using the above method.

Abstract: Short peptides are provided, which bind to a body fluid sample obtained from a schizophrenic patient at a substantively higher level than to a body fluid sample obtained from a non-schizophrenic individual. The peptides are no more than 10 amino acids long and comprise a continuous sequence of at least 5 amino acids which consists of at least one positively charged amino acid at one of its ends. The provided peptides, which are the putative binding sites of autoantibodies found in high levels in schizophrenic individuals, are thus useful in diagnosis of schizophrenia.

Abstract: An assay for the diagnosis of multi-infarct dementia and dementia of the Alzheimer type in an individual is provided. It comprises the steps of obtaining a sample from said individual being a blood sample, a platelet-containing fragment thereof, or a fragment containing platelet associated antibodies (PAA) detached from the platelets, and then determining the level of a platelet associated antibody against a 75 kD platelet-protein in said sample. A level higher than that of a control sample indicates that said individual has a high likelihood of having multi-infarct dementia or dementia of the Alzheimer type.

Abstract: A pharmaceutical composition for the treatment of schizophrenic disorders that comprises a pharmaceutically acceptable carrier and as active ingredient an immunosuppressive agent.