TH and Hashimoto thyroiditis: To date, the GWAS of TPO antibodies has not shown a strong heritable signal (h2SNP <0.002), probably due to a combination of limited statistical power and the fact that it was performed in population-based cohorts after excluding individuals on thyroid medication, effectively excluding most of the subjects with diagnosed Hashimoto's hypothyroidism.44 Therefore, future larger GWASs of (thyroid) autoimmune biomarkers and conditions will help elucidating whether the thyroid-mood axis is predominantly mediated through TH levels or pathways involved in (auto)immunity.