It has been shown in animal studies that nicotine addiction is strongly potentiated by some of the other substances (IIRC is primarily the MOAIs) present in tobacco.
That said, I'm quite strongly dependent on caffeine. We're now approaching 48 hours into a power outage due to an ice storm at our hunting cabin and you should seen the effort I went to to make coffee yesterday morning. Heating water was no problem, but then I realized: Oh crap, we only have whole-bean coffee and the grinder requires electricity.