Though raised in a Buddhist family, she gradually lapsed from the faith as an adult.

lapsed 是动词 lapse 的过去式形式。lapse 原意是"滑落、流逝"，引申为"逐渐偏离、放弃（信仰或习惯）"。这里指她逐渐脱离了原本的宗教信仰。