Author here. Thanks! I'm pretty sure most of the negative effects of SSRIs were discovered in phase 2 trials, though. Pk trials aren't usually powered to find adverse effects in subpopulations like teenage patients. Same thing with GLP-1 agonists and their effects on addictions (which I think were actually discovered post approval).

That being said, we'd still have to do dose escalation studies for toxicology even if we had great pbpk models. Not denying that.