I recently did whole genome sequencing at a 30x depth, so the real deal, and I am homozygous for the rs3892097 mutation, which is CYP2D6*4/*4. CYP2D6 is very polymorphic, so there's a ton of different types people can have, but I too have no CYP2D6 activity. I searched and found this thread on Google, very interesting you mention terbinafine. I have been on Adderall for ADHD for many years with no issue (only that XR lasted way too long so I switched to IR), but a few years ago I was put on Lamisil to help treat a fungal infection on my nail. Holy sh*t, it was the worst experience of my life. Like, for an entire month, I felt like I was losing my damn mind. I was sleeping terribly, I was feeling agitated as hell, and I simply just felt absolutely fucked up. I quit the terbinafine, and within 1-2 weeks I was back to normal. I think the combo of the Adderall and terbinafine, in trans to my CYP2D6 mutation just made it a nightmare experience for me. Anyway, just thought I'd share that. I even told my psychiatrist, "I think this antifungal is messing with my head". Luckily, he didn't think I was crazy. Fascinating stuff.