Caffeine and nicotine are thought to have evolved in plants due to...
· Comment — Christine Peterson's post · View on Facebook · Markdown source
Caffeine and nicotine are thought to have evolved in plants due to their insecticidal / herbicidal properties initially. So, it's not implausible on its face for glyphosate to have psychoactive effects. But if it did, I'd expect to hear more reports of gardeners / farmers getting high during its application. To my knowledge, there are no such reports.