Well I will offer what little I know but aside from a few acquaintances I've had over the years I don't know much about the science behind this disorder. I will say that when I first started vaping I wondered if it was giving me anxiety, I lowered (and continue to lower) my nic strength and eventually it subsided, I'm sure some or maybe all of the anxiety I experienced could have been attributed to the withdrawal effects from analogs too.
I will say that I have heard many times that the nicotine from smoking actually helps with schizophrenia symptoms, and I believe that is a well documented fact.
Whether or not your ejuice is making your symptoms worse because of other chemicals present in the flavors sounds a bit far fetched to me, but stranger things have been true. Perhaps it is well worth investigating? Let's not forget that nicotine is a stimulant, any stimulant can certainly aggravate anxiety, it can also help alleviate it, whichever way it goes I'm sure is dosage dependent. Let's also recognize that regular cigarettes have a host of chemicals in them that combine with the nicotine to produce a different psychoactive effect, while with ecigs you are getting the nicotine only (stimulant). It probably wouldn't hurt to at least try lowering your nic content, as well as some organic and healthier juices out there that vendors such as Ahlusionm, Heathers Heavenly Vapes and Virgin Vapor have to offer to see if you experience any improvement.