Here's a timely question, given established facts and recent events: Is Ketamine Neurotoxic? Desmolysium, M.D., a former user of the dissociative and hallucinogenic anesthetic, seems quite convinced.
At recreational doses, ketamine is addictive, destroys the bladder, and is toxic to the central nervous system. Microscopic lesions (including but not limited to so-called "Olney's lesions") in both grey and white matter are evident already after three months of high-dose ketamine use. By year three of heavy use, MRI scans of ketamine users often reveal a brain that looks like a mix between multiple sclerosis (white matter lesions) and Alzheimer's disease (grey matter atrophy). Ketamine abuse is well known to cause widespread cognitive and neurological impairment. However, the average ketamine "user" consumes 500-1000mg of ketamine per day, which is 100-300x as much as therapeutic use (0.5mg/kg). One glass of wine per week is surely different from a gallon of vodka per day.
If the medical question of whether it's is safe to use ketamine at "low therapeutic doses at reasonable frequencies for a couple of weeks or months" has been answered positively, the question of "sprinkling it on breakfast like confectioner's sugar forever" remains outstanding!
