We hypothesized that glycine serum levels might be associated with intensity of negative symptoms in schizophrenia. In our study we found mean glycine serum levels to be significantly lower in patients than in controls.
That difference was only caused by findings in the male study population. Glycine serum levels were negatively associated with intensity of negative symptoms assessed by the PANSS negative subscale and the SANS total scores in the patients.
These data suggest a possible implication of NMDA receptor dysfunction in the pathogenesis of negative symptoms in schizophrenia.