Although I've read that there are three types of tolerance, molecular cellular and behavioural, I cannot seem to find any mechanism of cellular other than desensitization of receptors. If someone can clear it up, or inform me that cellular tolerance is not a thing, that would be much appreciated <3
Personally, I find these distinctions a bit silly but I also understand they have some use.
People sometimes divide neuroscience into molecular, cellular, and systems levels of understanding. Molecular covers all the "one cell" phenomenon: expression of particular receptors or related proteins, for example. Cellular is one step above of molecular and considers the collection of all "molecular" entities and also considers a circuit level, recognizing that neurons exist among other neurons. Systems level neuroscience sometimes ignores these low-level interactions and sometimes embraces them, but overall is more connected to the behavior and state of the whole organism, approaching psychology.
The reason I think this separation is a bit silly is because, well, none of these levels of understanding are independent. That said, it's a good framework especially for novices to drive home that stuff happens at different levels of explanation. This is true for drug abuse as it is for many other concepts in neuroscience. It also lets someone that is writing a textbook focus on these different levels of explanation in sequence, in a way that is easier to process. A professional in the field is unlikely to draw the same boundaries, but they also have enough background to consolidate knowledge at all levels of interest.
I included a reference that makes the same distinctions I'm making here, but it's likely to be hard to find a canonical one. Different textbooks are going to draw different boundaries as they explain what we know in their own ways, and that's okay. I hope students recognize that A) There are different levels of explanation for neurobiological phenomenon, and B) These levels are interconnected. It's important to recognize that it's possible to study addiction at these different levels of abstraction; it shouldn't be important to draw boundaries between them, however.
Pietrzykowski, A. Z., & Treistman, S. N. (2008). The molecular basis of tolerance. Alcohol Research & Health, 31(4), 298.