Awesome to see mention of this, as I think this situation disproportionately effect neurodivergent (ASD, ADHD, people w neurological conditions) more. I personally think everyone should test the liver enzymes and MTHFR before administering antidepressants. It's not perfect, but it can give an idea about absorption and clearance rates or impairments so the doctors can adjust dose or timing. This scenario happened to me bc I kept having terrible side effects no matter what the antidepressant. I personally have a mutation where I need very little, the lowest children's dose, to get the same effect as an adult. I was taking at least 5x more than I needed by taking an adult dose, so I was becoming ill from every pill. I like the idea of antidepressant use being much more investigative than it is now. If a Holy Grail BBB permeability test ever existed that would be amazing.