Serum levels of interleukin 6 in schizophrenic patients during treatment augmentation with sarcosine (results of the PULSAR study).

Abstract

Augmentation of sarcosine, a natural inhibitor of the glycine transporter type I, normalizes glutamatergic neurotransmission, having beneficial impact on primary negative symptoms in schizophrenia and may also influence immune system and interleukin 6 (IL-6) levels. Finding a relationship between initial IL-6 serum concentrations or its changes and severity of symptoms as a result of sarcosine addition to stable antipsychotic treatment. Fifity-eight individuals with schizophrenia with predominantly negative symptoms completed a 6-month randomized, double-blind placebo-controlled prospective study. Patients received 2g of sarcosine (n=29) or placebo (n=30) daily per os. We measured IL-6 levels and severity of symptoms at the beginning, after 6weeks and 6months. As main clinical tools, we used Positive and Negative Syndrome Scale (PANSS) and Calgary depression scale for schizophrenia (CDSS). Augmentation with sarcosine had no effect on IL-6 serum levels in all time points. We noted significant improvements in negative symptoms, general psychopathology, and total PANSS score in the sarcosine group. We found correlation of initial serum IL-6 with severity of positive symptoms and negative association between IL-6 levels reduction and positive symptoms reduction. Sarcosine does not significantly affect IL-6 concentrations but IL-6 may be involved in mechanisms related to the presence of positive symptoms.