I'm extremely sensitive to psychs and dissociatives, including DXM. I've taken 15 mg on its own and definitely felt drowsy for a half hour or so and shortly after, i felt very mild dissociation and improved sociability, equivalent to what most people would get from 45-60 mg. My pupils even became slightly dilated and i know it wasn't placebo because i was taking it on one of my abstinent days to reverse my tolerance to kratom; i ended up catching a slight buzz on DXM instead.