In general, accounts will converge on ketamine being more psychologically addicting than the other drugs you mention. With psychological addictions, there are many variables at play that make it depend on the individual in question.A few years back, I knew a man who, by credo, distributed only psychedelic drugs and no other category of drug. He recounted that ketamine was the only drug he sold, for which there were incidences of people coming to his house banging on his door in the middle of the night trying to get the drug.
I've never had an issue with ketamine personally. I've had grams of ketamine lying around for years, only taking them out once or twice a year to have a session, and that's it. I know others who cannot have any in their possession for long, since as Infinite pointed out above, it's much more convenient to use than other psychedelics (shorter duration, etc.), and so much easier to rationalize usage at an inopportune occasion.
As for caffeine, I find that to be far more psychologically addicting than ketamine ever has been for me, particularly if you use it for work or other purposes in which you need to stay concentrated. Ketamine's just an intense, interesting experience of exploring my mind. Caffeine is something that helps me get through the day. Way different kind of psychological addiction occuring there, in any case.