The exact cause of attention-deficit/hyperactivity disorder (ADHD) is not fully understood, but research suggests that it is likely caused by a combination of genetic, environmental, and neurological factors.
Genetic factors: ADHD tends to run in families, which suggests that there may be a genetic component to the disorder. Studies have identified a number of genes that may be associated with an increased risk of developing ADHD. According to research, parents and siblings of someone with ADHD are more likely to have ADHD themselves. However, the way ADHD is inherited is likely to be complex and is not thought to be related to a single genetic fault.
Environmental factors: Research has shown that certain environmental factors may increase the risk of developing ADHD. These factors may include:
- Exposure to toxins, such as lead, during pregnancy or early childhood
- Premature birth or low birth weight
- Complications during pregnancy or delivery
- Exposure to tobacco smoke or alcohol during pregnancy
Neurological factors: Research has also suggested that differences in brain development and functioning may play a role in the development of ADHD. For example, certain areas of the brain may be smaller in people with ADHD, and there may be differences in the levels of certain chemicals in the brain (neurotransmitters) that are involved in controlling attention and behavior.
Groups at risk
Certain people are also believed to be more at risk of ADHD, including people:
- who were born prematurely (before the 37th week of pregnancy) or with a low birthweight
- with epilepsy
- with brain damage – which happened either in the womb or after a severe head injury later in life
It’s important to note that the cause of ADHD is likely complex and multifactorial, and more research is needed to fully understand the underlying mechanisms of the disorder.