trial. Standard unblinding procedure revealed that the patient had been taking sarcosine throughout the course of the study. This case with recently published observations indicates the need for revision of the recommended dosage of sarcosine or concomitant drugs in patients with schizophrenia, as well as the need to take the risk of serotonin–glutamate interaction into consideration. In a previously reported case, we decreased the dose of sarcosine; here we decided to reduce the dose of antidepressant with similarly good effect. 25
