This is such an interesting observation. It may be true that worldwide it is MORE common to mix cannabis with tobacco than to not. But we wouldn't think that in the United States, because it is much more rare here.
Older cannabis users are more familiar with spliffs, and there are some sub-cultures where it is common, but it is not the norm here.
Do you mean head change? Basically a dizzy/foggy/rolling feeling mainly in the head.
It gets less extreme with tolerance, similar to cannabis highs.
Yah I never got a gentle dizzy rolling feeling.
Instead it felt like my brain was guitar strings and they were being plucked and vibrating. Then another. And another. They were very sudden, pluck/vibrate, and sped up the longer I smoked tobacco.
I did that pipe for about 20m. They sped up to about 3/second around the 10m mark. They finally quit at the 30m mark (10m after stopping).
I'm sure they slow down with tolerance. I just know I didn't like the feeling even starting.
Either way, there were brain pops that were happening around inside my head that I did absolutely not like. Not sure how others describe the nicotine phenomenon. I just know I didn't like that one bit.