I'll put in my 2 cents.
Im a general anxiety sufferer. I quit smoking 2 years ago. Discovered vaping 2 months or so in, but didn't want to vape any Nic so went with 0mg. Had some panic attacks during this time, but not sure if vaping had any direct connection with it as I had 0mg. (although I felt like crap every time I did PG based juices) Plus at the time it seemed like a pain to find anything with Nic in Canada, plus wanting it all VG. I really didn't vape much at all and gave it up....until recently. I switched jobs and low and behold there are about 4 vapers here lol
Anyway I started getting some more panic attacks as of late, and I attribute those to the new changes in my life. Plus I have hypochondria, so any little weird thing with my body can set me into a panic...I would pick up and Ecig now and then, (but would be months in between) until recently, seeing that there are some fellow vapers at the office I started to get into the vaping mood.
So I decided to get some low nic VG juice from a co worker (5mg) here and i must say, since I have started to use it, I feel more "calm". Quitting smoking does a number on you, even way after the fact. I've also read doing some google searching, that Nicotine can have effects on moods/depression/concentration etc. Its surprising!
That being said I often wonder about these super "mods" and chain vaping like its a pacifier. To much Nic can certainly trigger anxiety. I try not to use my e-cig all that much, mainly at work and try to treat it like a cigarette, having to stop what Im doing to use it, and for like 5-6 mins at a time. I was kind of disappointed in myself for vaping with NIC since I've gone all this time without it, but in the same regard, I think I would have caved and had a real smoke with the recent string of panic attacks. I'd would totally vape with NIC over a real cigarette any day. All that other S$%t in smokes Im sure does a number on your noggin.