I don't know if I had a clinical deficiency — I never got tested. But after Invega, intramuscular B‑vitamins (B1, B6, B12) helped me feel better
I think they were prescribed because I felt really awful — I had severe rigidity (I could barely move), trouble speaking, chewing, and even just thinking. I had very severe side effects that appeared right after the last injection. The vitamins were prescribed by a doctor, after a course of IV amantadine. I think if the doctor considers it necessary, the vitamin course could be repeated