Meanwhile, eight studies showed that people living with HIV with lower CD4 (lower than 200) or in the AIDS stage had poorer mental health status [18,19,42,50–52,79,101], including depression, anxiety, suicidal ideation, and NP impairment, while another six studies reported that there was no association between CD4 count or being diagnosed with AIDS and mental health [19,21,58,67,89,91]. This evidence concerns the gene CD4 and major depressive disorder.