According to pfeiffer, overmethylators have very low folic acid levels and high copper levels. Personally I dont know how convinced I am of about the copper as of late, but I do know, taking folic acid or methylfolate or anything else that is supposed to help overmethylators has tremendously helped my paranoia/anxiety/sleep issues and emotional bluntness(less blunt emotion). Funnily enough if you look on google one of the "side effects" of folate or folic acid is "depressed or overly excited".
If an undermethylator takes folate, they can become depressed, if an overmethylator does, the opposite happens, excitement. I never got anxiety from methylfolate though I read some are sensitive to the methyl. Thats the best way to describe myself when I take lots of methylfolate(what Im currently taking now), makes me feel like a new person and its not an exaggeration. Gets rid of my strong emotional bluntness. I suppose I am not sensitive to methylfolate's methyl group then others, but you may be. Folic acid may work better for you as to not add more methyl.
Copper and folate do not impact or deplete each other right
I thought folate promotes overmethylation, along with b12 while low levels of either are common in undermethylators