Fig. 1. Visual summary of the three core aims of the current meta-analysis.

Aim 1 (orange and light blue): estimate family-based genetic (h²), shared environmental (c²) and non-shared environmental (e²) influences as well as SNP heritability (h²_SNP) for all NDDs identified by the DSM-5. Aim 2 (orange and red): provide grand estimates of family-based genetic (r_A), shared environmental (r_C) and non-shared environmental (r_E) correlations and SNP-based genetic correlations ($r_{{\mathrm{G}}_{\mathrm{SNP}}}$) between different NDDs. Aim 3 (navy blue and red): provide grand estimates of r_A, r_C, r_E and $r_{{\mathrm{G}}_{\mathrm{SNP}}}$ between NDDs and DICCs. The results for c², e², r_C and r_E are presented in Supplementary Note 1.