The protein/peptide profile of CSF was found to be characteristically altered in paranoid schizophrenia patients, with the key alterations being the prominent up-regulation of a 40-amino acid VGF peptide and the down-regulation of transthyretin at ~14 kDa along with a peptide cluster at ~6,800–7,300 Da that appeared co-regulated with the transthyretin cluster. Here, VGF is linked to schizophrenia.