This apparent mood stabilizing effect, which nevertheless blunted the beneficial effects of TSD on anhedonia, contrasts with the effects of P2X7R antagonism on stress-induced anhedonia seen in animal experiments, [28, 29] in which resolution of the deficit in drinking sucrose-water (anhedonia) was observed in mice receiving brain penetrant P2X7 antagonists. The gene discussed is P2RX7; the disease is Tay-Sachs disease.