There was a study done back in the 1980's that found that smokers in general were more productive. I smoked because I was very hyper, so any correlation the study found may have been reverse.
A lot of habitual drug users are often inadvertanly self medicating something. In terms of overall health, this,generally backfires, but in the moment, it actually works.
Most habitual, heavy smokers seem to light up when stressed as a cool down time. I do, my dad does, every smoker friend I ever had (and since my main source of friends at college was people I met smoking, this is a large number) does.
When a smoker is stressed, they go smoke. Five minutes later, they've relaxed, calmed down and are ready to work again.
*shrug*
At work, I can tell you that a smoking break after working on a dog that is breaking my everlasting nerve makes it possible for me to go on to the next dog without me wanting to slaughter. If I quit smoking, I'm not sure what excuse I'll use to just walk away from dogs with a death wish.
The local hospital has a no smoking on grounds for everyone (workers, patients, and visitors) which I think is retarded, at least for those who arn't employees. I havn't had to take Dad in since the policy went into place for his semi annual trip to the ER for fluids, cause he's sick as a dog and refused to go to the doctor when I told him too, but it's gonna be intresting when that time comes around. When dad is stressed and unable to smoke, it doesn't go well for anyone. There is a time and a place to push the no smoking agenda. The middle of the night with a dehydrated, grumpy old fart who's stressed out because he had to go to the ER is not that time.
I think there are grounds for medical employees who work with patients for not hiring smokers. The smell does stick and having a patient who is allergic or for some reason could be stressed out by it is possible. For the same reason, the same people also should avoid heavy perfumes and such.