Attention-Deficit/Hyperactivity Disorder: A Comparative Analysis of Genetic and Psychosocial Origins in Recent Research

Abstract

Attention Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental condition that affects approximately 5–10% of children and 2.5% of adults worldwide. This comprehensive review examines the relative contributions of genetic and psychosocial factors to the etiology of ADHD through the analysis of twin studies, genome-wide association studies (GWAS), environmental research, and gene–environment interaction studies. Current evidence indicates that ADHD is highly heritable, with heritability estimates consistently ranging from 70% to 80% in twin studies. Recent GWAS have identified 27 genome-wide significant loci explaining approximately 22% of the phenotypic variance. However, environmental factors such as prenatal exposures, psychosocial adversities, and toxin exposure also significantly contribute to the development of the disorder and the severity of its symptoms. Emerging epigenetic research suggests that gene–environment interactions through DNA methylation and histone modifications may provide a mechanistic link between genetic predisposition and environmental triggers. This study concludes that ADHD represents a complex interplay between significant genetic susceptibility and modifiable environmental influences, supporting a multifactorial model rather than a purely genetic or environmental explanation.

Keywords

• ADHD
• genetics
• environment
• heritability
• twin studies
• GWAS
• gene-environmental interaction
• epigenetics

Dikkat Eksikliği ve Hiperaktivite Bozukluğu: Genetik ve Psikososyal Kökenler Güncel Araştırmaların Karşılaştırmalı Analizi

Abstract

Dikkat Eksikliği/Hiperaktivite Bozukluğu (DEHB), dünya çapında çocukların yaklaşık %5-10'unu ve yetişkinlerin %2,5'ini etkileyen yaygın bir nörogelişimsel durumdur. Bu kapsamlı derleme, ikiz çalışmaları, genom çapında ilişki çalışmaları (GWAS), çevresel araştırmalar ve gen-çevre etkileşimi çalışmalarının analizi yoluyla genetik ve psikososyal faktörlerin DEHB etiyolojisine göreceli katkılarını incelemektedir. Güncel kanıtlar, DEHB'nin oldukça kalıtımsal olduğunu ve ikiz çalışmalarında kalıtım tahminlerinin sürekli olarak %70-80 olduğunu göstermektedir. Son GWAS çalışmaları, fenotipik varyansın yaklaşık %22'sini açıklayan 27 genom çapında önemli lokus belirlemiştir. Bununla birlikte, doğum öncesi maruziyetler, psikososyal olumsuzluklar ve toksin maruziyeti gibi çevresel faktörler de bozukluk gelişimine ve semptom şiddetine önemli ölçüde katkıda bulunmaktadır. Yeni ortaya çıkan epigenetik araştırmalar, DNA metilasyonu ve histon modifikasyonları yoluyla gen-çevre etkileşimlerinin, genetik yatkınlık ile çevresel tetikleyiciler arasındaki mekanik bağlantıyı sağlayabileceğini öne sürmektedir. Bu çalışmamda, DEHB'nin önemli genetik yatkınlık ile değiştirilebilir çevresel etkiler arasında karmaşık bir etkileşimi temsil ettiği ve salt genetik veya çevresel bir açıklamadan ziyade çok faktörlü bir modeli desteklediği sonucuna ulaşılmıştır.

Keywords

• DEHB
• genetik
• çevre
• kalıtım
• ikiz çalışmaları
• GWAS
• gen-çevre etkileşimi
• epigenetik

Supporting Institution

İstanbul Aydın Üniversitesi

Ethical Statement

bu çalışma literatür taramasına dayalı olup herhangi bir deneysel uygulama içermediğinden etik kurul onayı gerektirmemektedir.

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