HCRTR2 and attention deficit-hyperactivity disorder: Using a SNP-based approach, there was no overlap in genomic risk loci or individual significant variants between ADHD (LD r2 < 0.1; Table S11) and PhoneUse (LD r2 < 0.1; Table S12) GWAS; however, individual significant loci from both GWAS map to genes involved in fear recognition/consolidation (sortilin related VPS10 domain containing receptor 3 (SORCS3)) in ADHD [50] and hypocretin receptor 2 (HCRTR2) [51] in PhoneUse) and language/speech development/impairment (Semaphorin 6D (SEMA6D) in ADHD [52] and forkhead box transcription factor (FOXP2) in ADHD and PhoneUse [53]).