[Proteomics: biomarker research in psychiatry].

Over the last decade, genomics research in psychiatry and neuroscience has provided important insights into genes expressed under different physiological and pathophysiological conditions. Contrary to the great expectations regarding a clinical use of these datasets, genomics failed to improve markedly the diagnostic and therapeutic options in brain disorders. Due to alternative splicing and posttranslational modifications, one single gene determines a multitude of gene products. Therefore, in order to understand molecular processes in neuropsychiatric disorders, it is necessary to unravel signal transduction pathways and complex interaction networks on the level of proteins, not only DNA and mRNA. Proteomics utilises high-throughput mass spectrometric protein identification that can reveal protein expression levels, posttranslational modifications and protein-protein interactions. Proteomic tools have the power to identify quantitative and qualitative protein patterns in postmortem brain tissue, cerebrospinal fluid (CSF) or serum, thus increasing the knowledge about etiology and pathomechanisms of brain diseases. Comparing protein profiles in healthy and disease states provides an opportunity to establish specific diagnostic and prognostic biomarkers. In addition, proteomic studies of the effects of medication - in vitro and in vivo - might help to design specific pharmaceutical agents with fewer side effects. In this overview, we present the most widely used proteomic techniques and illustrate the potential and limitations of this field of research. Furthermore, we provide insight into the contributions of proteomics to the study of psychiatric diseases such as Alzheimer's disease, drug addiction, schizophrenia and depression.