The two biggest 'pot heads' I know both had a severe illness from smoking weed and both of them refuse to acknowledge it's the weed doing it. It's a debilitating condition, they vomit all day, go into shock and have to get thrown into hot showers regularly to ease the pain. I'm sure it's not as common as alcoholism but good god, it doesn't look fun.
[0] https://www.cedars-sinai.org/health-library/diseases-and-con...