Objectives. The article presents the results of two prospective clinical studies using glutamatergic system modulators – glycine and sarcosine, as conducted in the Department of Affective and Psychotic Disorders at the Medical University of Lodz.
Material and methods. In both studies, participants were previously diagnosed with schizophrenia with predominantly negative symptoms. The inclusion criteria included a stable mental state and established dosing of antipsychotic drugs. In both projects we monitored the efficacy of glutamatergic drugs on the symptomatology of schizophrenia with the PANSS scale as the primary assessment tool.
Results. In the first project – designed as an open-label study – we monitored the effect of glycine (0.8 g/kg of body mass, max. 60 g per day), NMDA receptor co-agonist during the 6-week administration of this amino acid. We noted a significant score reduction in negative symptoms and general psychopathology subscales and in total PANSS. In the second project a randomized, double-blind placebo-controlled 6-month trial, we evaluated the efficacy of sarcosine (2 grams per day), glycine transporter type 1 inhibitor. In this study we demonstrated a significant improvement in negative symptoms and general psychopathology, as well as in the total PANSS score in the sarcosine group. In the placebo group, changes were insignificant.
Conclusions. Glycine and sarcosine were effective and well tolerated by the patients.