Symptoms of induced hypomania appeared later than those associated typically with the beginning of antidepressive treatment, but occurrence of hypomania or mania during antidepressive treatment is possible at different times. Because a hypomanic state was not present with stable venlafaxine and olanzapine doses, we assume that adding the sarcosine was of crucial importance. Mechanisms of the glutamatergic impact on serotoninergic functions are actually not clear; we cannot clearly explain the 10-week delay of discomfort appearance after sarcosine starting, and this period is longer than the delay of selective serotonin reuptake inhibitors’ and other antidepressants’ effect (usually 2–4 weeks). Based on both this report and previous observations, we perceive that proper simultaneous use of substances with glutamatergic and serotoninergic properties may generate a synergistic effect, which can also be used in refractory cases.25,30
