When the US went through the same thing, it superficially seemed like cigarettes were largely replaced by caffeine, particularly in the form of "energy drinks"

When the US went through the same thing, it superficially seemed like cigarettes were largely replaced by caffeine, particularly in the form of "energy drinks" like Red Bull and 5-Hour Energy. It's possible that this is just a coincidence, though. As to what specifically the need might be, there's a good bit of circumstantial evidence to suggest that nicotine relieves or compensates for some symptoms of schizophrenia, ADHD, and related disorders.