ESR2 and Anxiety: Similar sex specificity underlies anxiety: Studies in rodents discovered that a particular isoform of the estrogen receptor (ERβ) decreases anxiety in females (Imwalle et al. 2005; Lund et al. 2005) while increased levels of circulating testosterone decrease anxiety in both sexes (Celec et al. 2015) via androgen receptors (Zuloaga et al. 2008).