GRM2 encodes the glutamate metabotropic receptor 2, a G-protein coupled receptor that mediates glutamatergic neurotransmission through group II metabotropic glutamate receptor activity 1. The gene is located on chromosome 3.1-p21.2 and consists of 5-6 exons spanning approximately 13 kb 21. GRM2 functions in synaptic transmission by negatively regulating adenylate cyclase activity and positively regulating PI3K/AKT signaling pathways, playing a crucial role in neuroplasticity and synaptic modulation. The receptor has been implicated in several psychiatric disorders, with genetic variants showing association with methamphetamine-induced psychosis in Japanese populations 3 and major depressive disorder 4. Expression studies reveal that GRM2 levels are decreased in alcohol use disorder patients and show significant recovery following treatment 5. Additionally, GRM2 expression is modulated by ketamine treatment, suggesting involvement in antidepressant mechanisms 6. Genetic variants in GRM2 also influence outcomes of antipsychotic treatments, affecting both efficacy and side effect profiles 7. These findings collectively demonstrate GRM2's critical role in glutamatergic neurotransmission and its potential as a therapeutic target for various neuropsychiatric conditions.