These variabilities can cause disparities in the course of depression, such as lower 5-HT neurotransmission, related to depression symptoms in women compared to men [17], lower expression of 5-HT1A autoreceptors in the prefrontal cortex of depressed women [18], and a higher 5-HT1A receptor binding ability in women compared to men [19]. Here, HTR1A is linked to major depressive disorder.