Postersession 3
Poster #: 21
Topic: Clinical applications (incl. consciousness)
Friday, Sep 11, 2015
1st floor

Relationship between MMN and monoamine metabolite levels in schizophrenia: preliminary results of cross-sectional and longitudinal studies

Tetsuya Shiga, Sho Horikoshi, Itaru Miura, Keiko Kanno-Nozaki, Kazuko Kanno, Yusuke Osakabe, Michinari Nozaki, Satoko Asano, Masayuki Hikita, Norikatsu Itou, Shuntaro Itagaki, Takashi Matsuoka, & Hirooki Yabe

Department of Neuropsychiatry, Fukushima Medical University, Fukushima, Japan

[Background] Mismatch negativity (MMN) deficit has been repeatedly demonstrated in schizophrenia, and may be associated with impaired the N-methyl-D-aspartate (NMDA) receptor function. Although it is known that the dopamine receptor don’t modulate MMN over the short term, it is unclear whether the dopamine system affects MMN in the long term. Therefore, we explored the correlation between MMN and plasma monoamine metabolites in schizophrenia patients in cross-sectional and longitudinal studies.

[Method] Experiment 1: We collected blood samples in 18 schizophrenia patients and recorded duration-MMN to the right-ear stimuli in this cross-sectional study. Correlations between MMN and levels of plasma dopamine and serotonin metabolites were explored. Experiment 2: 14 schizophrenia patients were enrolled into this longitudinal study. The antipsychotic drugs of all patients were switched to other antipsychotics for the improvement of clinical symptoms or side effects. Duration-MMN to the right-ear stimuli and dopamine and serotonin metabolites level were measured before and 4 months after the switching and the correlations between the change in MMN and changes in monoamine metabolite levels were explored.

[Results] Experiment 1: A significant negative correlation between the amplitude of MMN and plasma levels of dopamine metabolites was observed. Plasma serotonin metabolite levels were not correlated with MMN. Experiment 2: We found no correlation between the changes in MMN and the changes in dopamine and serotonin metabolites level and.

[Conclusions] The strong blockade of dopamine receptors in schizophrenia may attenuate MMN over the long term. However, larger sample size is required in future studies in this area.