i think alot of these studies lack one thing as well, in fact, i know they do.
consistent, quality, cannibus... i bet studies would look completely different (as if you cant studies that vary widely already, and the reason they do) if you took a quality, organically grown, classic, strain of cannibus.
I tend to make the same argument. Nobody can deny that the 'possibility' for withdrawals are there, but for most users they symptoms seem to be so tame that they go unnoticed, or are mild enough to be written off as insignificant.
And about that argument, I often remind people, especially those who say 'i tried weed once, I didn't like it', that there are many different kinds of cannabis with a multitude of effects that are often specific to the type.
My analogy is that of an apple. If someone comes up and says "I tried an apple once, it was too bitter", wouldn't any reasonable person respond with "What kind of apple did you try? Was it a granny, red, sweet, etc. etc.??? Because even though they are all apples, they can have wildly different tastes.
Or.. another that I know personally. I don't like wine, in general, but my experience in tasting wines is very limited. I had gone to many wine tastings and walked away without having a single drop of wine that tasted good to me. It wasn't until going to a winery with a friend, with no intention of trying any more wines, that she insisted I try a sweet, strawberry based wine, and I basically loved it, and proceeded to drink the entire bottle.