This study was introduced to me by a colleague of mine who has suffered with intrusive tinnitus since 2014. I searched around on the forum and have not come across any details or awareness of this particular study so I thought I'd share it. If this has been discussed before, my apologies and please have it merged with any ongoing thread.
That said, Columbia University Department of Psychiatry in New York City is currently performing Phase 2 trials investigating the effect of ketamine on tinnitus and it appears that it is on a rolling recruitment cycle. Considering I live in the area, I provided them with my contact information this afternoon and am currently awaiting for them to get in touch regarding trial info and requirements. If I get any feedback from them, I'll provide updates with any details I receive.
Link for the Columbia University Medial Martinez Lab:
https://www.columbiapsychiatry.org/research-labs/martinez-lab
Link for Clinical Trial Information:
https://clinicaltrials.gov/ct2/show/NCT03336398
Heads up for anyone interested: the trial does require two MRI scans. I know there is a lot of hesitation when it comes to MRI's on this forum, and for good reason, but I think it's a chance I would personally be willing to take as there have been anecdotal reports of ketamine potentially impacting the pitch and loudness of tinnitus in a positive way.