At the beginning of the study, no significant difference was noted between groups with regard to PANSS score (71.4 ± 14 vs. 73.3 ± 13 points in total score for sarcosine and placebo groups, respectively; p = 0.6736). However, at the end of the experiment, patients treated with sarcosine had significantly lower results (57.7 ± 15 vs. 71.5 ± 13 points for sarcosine and placebo group, respectively; p = 0.00487). Changes in the negative PANSS subscale followed the trends of the total PANSS subscale. At the beginning of the study there was no significant difference between groups (25.4 ± 5.2 vs. 26.1 ± 5 points for sarcosine and placebo groups, respectively; p = 0.45085). While the negative PANSS score decreased significantly in both groups (25.4 ± 5.2 vs. 18.6 ± 6.1 for the sarcosine group, p = 0.0000; and 26.1 ± 5 vs. 25.4 ± 4.7 for the placebo group, p = 0.03031), this decrease was greater in the sarcosine group (18.6 ± 6.1 vs. 25.4 ± 4.7; p = 0.00001). The difference in metabolite ratios and negative PANSS subscale
