Did they, or the hospital, refer you to another Dr? If so then you should be contacting that Dr.
As for the study. In my experience if a Dr. feels a study would be a good fit, then they provide me with information on how to contact the study's in-take people along with how to apply, and what the criteria for acceptance are. If they haven't and you're interested you might have more success contacting the Drs' assistants and saying you're looking for study info.
It's been my experience that inpatient Drs don't follow up with you once you've been discharged.
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"I danced in the morning when the world was begun. I danced in the moon and the stars and the sun". From my favourite hymn.
"If you see the wonder in a fairy tale, you can take the future even if you fail." Abba