I think we are missing the big point in threads like these. The real question to address here is why experienced smokers suddenly become terrified with what by now should be familiar grounds for them.
I mean, there has to be an explanation as to why people, who normally experience the high as relaxing and non-threating, suddenly become overwhelmed with the mindfuck it gives.
I know that at least for me, the anxiety experience was carried over from bad stuff I had on heavy psychedelics in the past. It's like once you become depersonalized one time, the impression stays with you forever, just waiting to pop up in a moment of weakness.
Earlier today I smoked way too much (~0.5 g) by my own, which is not uncommon for me (high tolerance and all), and I just went into a world of total mindfuck and ego softening.
You know how usually you don't remember the anxiety and fear so much once the high becomes a smooth experience? And the next time you dose, all those scary stuff hit you back again, and you're like, "Shit! If only I remembered how bad this gets, I would have never done it again!"
Well, this time I made a conscious effort to memorize the fears I had so I can remember and analyze them later, and I really made them to stick with me. I feel like I have more of a grip on them right now, but than again that's what I always say to myself utill another bowl completely blows my mind away.
I'm really not sure whether to dose again right now or not. oh maybe a little bit

.
Back to the topic anyway, a lot of people believe that stuff that you learn while on cannabis can only be truly encountered and understood once more while on more cannabis. I find this to be very true.
In this same way are also the fears. Forget about rationalizing the anxiety experience as to 'immune' yourself against future episodes, because it hardly ever works. The way to deal with it is to look back on your life. Something there has to point out to development of new stress and problems, which later manifest themselves during a smoking session. Other than that, I'[m really clueless as how to counter anxiety.
I feel as though my anxiety stems from me trying to fight the effects of the drugs, instead of just going with them, which I fear might lead to a full blown ego death. I think I actually have a case of clinical PTSD from lossing my ego in the past.