Mann–Whitney U tests between patients taking medications and those who were unmedicated at the time of blood draw revealed no effect of current antipsychotic medication on cytokine levels in the schizophrenia sample (all p > 0.126) but did show higher IL-2 levels in unmedicated patients with bipolar disorder compared to medicated patients with bipolar disorder (U = 0, p = 0.003). This evidence concerns the gene IL2 and bipolar disorder.