The exact causes of Adult ADD (Attention Deficit Disorder) are not fully understood, but research suggests that a combination of genetic, neurological, and environmental factors plays a role in the development of the disorder. Genetics is thought to be one of the most significant contributors, as ADD often runs in families. If one or both parents have ADHD or a similar attention-related disorder, their children are at a higher risk of developing ADD. Studies have identified certain genetic variations that may influence brain function, particularly in areas related to attention, impulse control, and executive functioning. While no single gene is responsible for ADD, the condition is believed to be polygenic, meaning that multiple genes likely contribute to its development.

Neurological factors also contribute to the development of ADD. Brain imaging studies have shown that individuals with ADD may have differences in the size or activity of certain brain regions, particularly the prefrontal cortex, which is responsible for regulating attention, decision-making, and impulse control. Chemical imbalances in neurotransmitters like dopamine and norepinephrine may also play a role in ADD, as these chemicals help regulate attention and focus. Environmental factors, such as prenatal exposure to tobacco, alcohol, or drugs, low birth weight, and early childhood trauma, can also increase the likelihood of developing ADD. While these factors may predispose individuals to ADD, they do not guarantee that someone will develop the disorder, and other genetic or environmental elements may also come into play.