The media have picked up on a study on the use of Ketamine for depression. The authors claim quite spectacular results ("like magic") and it is possible that patients who read this are going to raise this with their GP's.
I think a little caution is advisable here. First of all it is only one study, and it is on rats. How do you know when or if a rat is depressed? The only evidence relating to Ketamine in depressed humans is purely anecdotal.
Secondly there is the issue of side effects. The article does mention the side effect of "short term psychotic reactions", which is worrying enough in itself. Bearing in mind that depression tends to require long term treatment there is a more worrying, and little known side effect, that of Ketamine Bladder. Long term Ketamine abusers can suffer this syndrome whereby over time the bladder fibroses and shrivels to the size of a walnut, meaning they have to pee every 15 minutes. It may be that this syndrome is due to the other things found in adulterated street Ketamine, but urinary symtoms have been reported in those on prescription ketamine.
Fortunately I doubt there are many, if any GP's out there who would consider prescribing this until much more hard evidence is available.