The purposes of the present invention is to develop and provide a mental illness determination marker that can easily and highly accurately determine the presence/absence of schizophrenia, depression or bipolar disease in subjects. Provided is a mental illness determination marker comprising: proteins made of a group consisting of amino acid sequences represented by sequence numbers 1-249 and included in cerebrospinal fluid; and a variant of the proteins or a segment thereof.
MENTAL ILLNESS DETERMINATION MARKER