Researchers measured the participants IQs at ages 5 and 10, then followed up with them at ages 16 and 30, asking about symptoms of psychological distress and drug use as part of a larger survey.

研究人员测量5岁和至10岁的参加者的智商，然后在他们16岁到30岁期间进行跟进调查，询问他们有关心理困扰的症状和药物使用情况，这是调查的重要的一部分。