Attention deficit hyperactivity disorder (ADHD) is thought to be a combination of genetic and environmental factors. Research suggests that ADHD has a strong genetic component, with estimates ranging from 60-90% of the variance in ADHD risk being attributed to genetics. However, genetics alone do not determine whether a person will develop ADHD, and environmental factors may also play a role in the development and expression of the disorder.
Studies have identified several genetic risk factors for ADHD, including variations in certain genes involved in neurotransmitter function, brain development, and stress response. However, the exact genetic mechanisms underlying ADHD are not yet fully understood, and more research is needed to fully understand the genetic basis of the disorder.
In addition to genetics, environmental factors such as prenatal exposures, early life stress, and social and family environments may also contribute to the development of ADHD. It is likely that the interplay between genetic and environmental factors plays a complex role in the development and expression of ADHD.