It isn’t a poison since there is no toxic level of it. The decision to seek medical help is certainly psychological since those who knowingly ingest pot don’t need medical attention and there is nothing medical that can be done about it. The only thing that is done for those who do go to a hospital is to give them reassurance that “everything will be alright.”
One thing to be done about it is to imprison people who gave them the toxic brownies without their knowledge.