Reading your post, it occurred to me that its tone sounds very similar to things I've written when I had had a lot of caffeine, or was on methylphenidate ("Ritalin") for a long time. In my case, prolonged methylphenidate use induced mild psychosis, a known effect that is common in long-term users of the pharmacokinetically similar amphetamine family, which also dramatically improves learning performance.

Thus extrapolating, I wonder if tDCS use might also induce psychosis.

Going off methylphenidate on the weekends ameliorated the psychotic effects, but some of the psychosis-induced beliefs persisted for quite a while.

I was 9.