People who are addicted to cocaine perform better at their jobs if provided with it versus those who are in withdrawal

Nicotine has a positive effect on memory. But lower blood oxygen levels and 300+ intentionally added carcinogens to make smoking more addictive probably has considerable adverse effect. People that hate smokers refuse to accept that there is a massive difference between tobacco and what is in cigarettes.

I've never smoked, but recently in my 30s started using nicotine gum 3-5 times per week.

It's amazing for improving focus, I get a lot more work done, remember things very well and am more patient with people.

Doesn't seem addictive in this form either, I can go a week without it and no withdrawal.

Also no negative impact on sleep (unlike caffeine)

Does it taste bad?

N=+1 for you on that one.

I quit smoking about 5 years before I was diagnosed with primarily-inattentive ADHD. Diagnosed with insufficient dopamine (uptake?), haha

There was a lot of burnout between the two, incidentally. At one point I'd decided to cut down on the caffeine too, it's almost like I was trying to burn out in hindsight :)