This is very different from drug company drug trials. I'd assume they are tried an tested antidepressants as the research doesnt sound like basic 'does this drug work and not cause your fingers to be amputated stuff' as much as how do these things really work. Someone in my dept works on the effect of antidepressants on taste and whether loss of or enhancement of a certain taste helps select the right treatment etc.
As an aside I took part, had a severe reaction, had to go home sick as a dog and couldnt pee for 6 hours
In general uni PhD projects wont do you much wrong.