My brother smoked heavily during his teens and as a result developed schizophrenia / substance induced psychosis. It was generally terrifying to see him unable to complete thoughts and lose his train of thought. He's fine now but I definitely wouldn't be surprised if you told me those years knocked a couple of points off his IQ. I'm for decriminalization and legalization but at the core we need funding for long term…
I'm sorry your brother developed it, but there's no saying that it was caused by weed