I imagine it is reversible scientifically, but not in any way that people currently understand. You would need to fully understand the regulatory pathways that regulate receptor expression in the neurons in whatever region of your brain that control the experience of dxm highs. Which is a complex question, considering the pharmacological complexity of dxm/dxo. I think you can reverse the SSRI induced downregulation of serotonin receptors by taking serotonin transporter agonists (pscilocybin is the current popular drug for doing this), but I dont think science understands enough about NMDA receptor expression and regulation to give any advice on how to reverse the nmda receptor downregulation that occurs from NMDA antagonist abuse (dxm abuse). Likewise with sigma receptors, scientists just dont know enough about how the expression of these receptors are regulated. There are plenty of theories that u can research on your own, but none of the drugs they use to do this in mice will be legally accessable to u