Not really something you should want to self medicate with at this point until more research is done.
The levels of ketamine required to form Olney's Lesions are 40mg/kg (given olney.txt), whereas the typical dose to reach a k-hole (the highest recreational level) is 1mg/kg. http://www.erowid.org/chemicals/ketamine/ketamine_dose.shtml Also: http://en.wikipedia.org/wiki/Olneys_lesions#Controversy
In addition, the dosage levels of recreational ketamine are lower than the anesthetic dosages of ketamine. Repeated use of ketamine would probably still cause problems though, though the problems would be more along the lines of general drug dependency and not being able to think straight.
> Not really something you should want to self medicate with at this point until more research is done.
I dunno. Depression can be really dangerous & costly too-- both from suicide and just generally not being happy in life.
It's fascinating to see these demonised recreational drugs being researched finally for their beneficial side-effects, sometimes in very small doses. Another one that comes to mind is the reported use of sub-psychoactive doses of LSD to combat the horror of cluster headaches.
He's been cluster-headache free since January, and he's really happy that he doesn't have to rely on the black market for medication.
http://en.wikipedia.org/wiki/Olney's_lesions