In comparisons between affective states within bipolar disorder patients, also adjusted for age and gender, mRNA levels of NDUFV2 (b=0.0414, 95% CI: 0.0170 to 0.0658), ESR2 (b=0.0007, 95% CI: 0.0000 to 0.0014), SP1 (b=0.0116, 95% CI: 0.0004 to 0.0229) and NUDT1 (b=0.0043, 95% CI: 0.0009 to 0.0077) were upregulated in a depressed state compared with a euthymic state. The gene discussed is ESR2; the disease is bipolar disorder.