string: In line with other authors who divided their sample into subgroups (normal versus borderline/abnormal) based on questionnaire scores [13,17,19–23], we created two ‘mental health’ groups: normal (cut-off point SDQ total score at follow-up #80th percentile; score #13) and borderline/abnormal mental health problems (cut-off point SDQ total score at follow-up .80th percentile; score $14) [26].