human 128 Humans 120 female 100 male 96 Female 90 Male 88 adult 72 Adult 55 middle aged 43 Article 42 Middle Aged 41 psychology 40 controlled study 39 major clinical study 38 adolescent 37 ethnicity 34 Adolescent 33 young adult 33 Young Adult 31 child 30 United States 29 ethnology 27 Hispanic 26 ethnic group 26 Child 25 Caucasian 23 article 19 African American 18 aged 18 genetics 17