Sarcosine,
glycine transporter inhibitor, increases
glycine levels around
NMDA receptor, improving primary negative symptoms of
schizophrenia. The aim of our study was to find a potential relationship between initial
TNF-alpha level, its changes and
schizophrenia symptoms severity, resulting from adding
sarcosine to a stable
antipsychotic treatment. Sixty subjects with stable
schizophrenia were randomized to receive either 2 g of
sarcosine or placebo and completed a 6-month, double blind, placebo-controlled study. Three patients on
sarcosine and one taking placebo did not complete
TNF-alpha tests, planned at the beginning, after 6 weeks and after 6 months. For clinical assessments we used PANSS and CDSS scales. No changes in
TNF-alpha serum concentrations in both groups at any time-points was noted. The
sarcosine group achieved significant improvement in negative symptoms, general psychopathology and total PANSS score group, however without any significant correlations between
TNF-alpha levels and PANSS scores in all assessments. Positive correlations between
TNF-alpha levels and CDSS score were found in the placebo group and total study group. Initial
TNF-alpha concentrations cannot be used as a predictor of the improvement resulting from adding
sarcosine.
Sarcosine does not significantly affect
TNF-alpha levels.
TNF-alpha may be involved in mechanisms related to depressive symptomatology in
schizophrenia.