She cries over small things lately, which the doctor says is due to hormonal changes during puberty.

hormonal 是由名词 hormone（荷尔蒙）加上形容词后缀 -al 构成的形容词，表示"与荷尔蒙有关的"。hormone 指人体内分泌腺分泌的化学物质，能调节生理功能和行为。hormonal changes 就是指"荷尔蒙水平的变化"。