Sarcosine

One-third of the patients with major depressive disorder do not respond to conventional antidepressants that act through the mono-aminergic system. The available treatment modalities, including SSRIs, are slow to act and have a lag time before showing improvement in symptoms of patients. To overcome these treatment hurdles, add-on therapy to standard antidepressant drugs may lead to better therapeutic outcomes. Sarcosine, which is a nutraceutical, modulates glutamate neurotransmission has an ameliorative effect on the disease symptoms of depression and negative symptoms of schizophrenia. The only clinical study done on depressive patients by Huang et al. cannot be generalized due to certain inherent limitations. To date, there is no randomized controlled trial with add-on sarcosine to current antidepressant therapy to the best of our knowledge. So, we considered sarcosine can be the candidate drug for add-on therapy due to its multiple mechanisms on the glutaminergic system. Adding sarcosine to ongoing antidepressant therapy may either increase their response rate or decrease adverse drug reactions by decreasing the dose requirement or may show a quicker therapeutic effect. Hence, the present randomized controlled trial has been planned to evaluate the efficacy and safety of sarcosine as add-on therapy in major depressive disorder.