Fig. 2

Cross-trait phenotypic (a) and genetic correlations (b) between SDQ-ADHD and SCDC scores during childhood and adolescence. Using the ALSPAC cohort, cross-trait phenotypic correlations (r _p) were estimated using Pearson product moment correlation coefficients (p ≤ 0.001) and cross-trait genetic correlations (r _g) were estimated with bivariate GREML. ALSPAC Avon Longitudinal Study of Parents and Children, GREML genetic-relationship-matrix restricted maximum likelihood, GREML-r _g bivariate genetic correlation, SCDC Social and Communication Disorders Checklist at 8, 11, 14 and 17 years (rank-transformed), SDQ-ADHD ADHD subscale of the Strength and Difficulties Questionnaire at 7, 10 12, 13 and 17 years (rank-transformed). r _g (p values): *p ≤ 0.05, **p ≤ 0.01 and ***p ≤ 0.001 (uncorrected for multiple testing, experiment-wise error rate p = 0.01)