Drugs can often be associated with abnormal psychological behaviors, but this is etymologically correlated in the word narcissism. Looking at it, you can extrapolate the prefix narc- (as in narcotics) but how far does this origin go? Narcissism has mythological origins, and was named after the man who fell in love with his own reflection, Narcissus. This came from Greek narkissos, which was a type of flower, presumably a lily. Narcotics come from the French term narcotique, which came from Latin narcoticum, which came from Greek narkotikon, which can be traced back to the Greek word for "numbness", narke. When etymologists compare narkissos with narke, there is a clear connection, especially when one considers that early drugs came from flowers. While this might come from the PIE root nerq, "to twist", this is doubtful and these probably trace back to the severely unexplored proto-Mediterranean language linguists know so little about. My guess would be something like nerk, which would probably be connected to the PIE word. We'll never know for sure, until time travel is invented, but in the meantime, if you're a narcissist, stay off the narcotics.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.