Chapter 4

Causes

The exact cause of ADHD is not fully understood, but research suggests that it is a complex condition influenced by a combination of genetic, neurological, and environmental factors. Some of the potential causes and contributing factors for ADHD include:

Genetic factors1 contribute significantly to ADHD, as multiple genes associated with the disorder have been identified, and the condition often runs in families.

Neurological differences2, including imbalances in neurotransmitters like dopamine and norepinephrine, as well as variations in brain structure and function, play a role in the development of ADHD symptoms.

Environmental factors3, such as prenatal exposure to alcohol, nicotine, or drugs, and other risk factors like lead exposure, low birth weight, and premature birth, can also contribute to the overall risk of ADHD.

Finally, psychosocial factors4, including family dynamics, parenting styles, and early life experiences, can influence the development and expression of ADHD symptoms, either exacerbating or mitigating their severity depending on the circumstances.

  1. Genetic factors

    Faraone, S. V., & Larsson, H. (2019). Genetics of attention deficit hyperactivity disorder. Molecular Psychiatry, 24(4), 562-575. Link ↩︎

  2. Neurological differences

    Cortese, S. (2012). The neurobiology and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD): What every clinician should know. European Journal of Paediatric Neurology, 16(5), 422-433. Link ↩︎

  3. Environmental factors

    Banerjee, T. D., Middleton, F., & Faraone, S. V. (2007). Environmental risk factors for attention-deficit hyperactivity disorder. Acta Paediatrica, 96(9), 1269-1274. Link ↩︎

  4. Psychosocial factors

    Johnston, C., & Mash, E. J. (2001). Families of children with attention-deficit/hyperactivity disorder: Review and recommendations for future research. Clinical Child and Family Psychology Review, 4(3), 183-207. Link ↩︎

Subsections of Causes

Genetic

Genetics play a significant role in the development of ADHD, as the condition tends to run in families.

Research has identified multiple genes associated with ADHD, each contributing a small effect to the overall risk.

While no single gene causes ADHD, the combination of multiple genetic factors can increase an individual’s susceptibility to the disorder.

Additionally, interactions between genetic and environmental factors may contribute to the development and expression of ADHD symptoms.

Neurological

Neurological factors also contribute to ADHD, with research showing differences in brain structure and function in individuals with the disorder.

Key neurotransmitters, such as dopamine and norepinephrine, are involved in regulating attention, impulse control, and other executive functions.

Imbalances or disruptions in these neurotransmitter systems can lead to the development of ADHD symptoms.

Moreover, studies have identified differences in brain volume, connectivity, and activation patterns between individuals with ADHD and those without the disorder.

Environmental

Environmental factors can also influence the development and expression of ADHD symptoms.

Prenatal exposure to substances such as alcohol, nicotine, or drugs can increase the risk of ADHD in children.

Other environmental factors, such as lead exposure, low birth weight, and premature birth, have also been associated with an increased risk of ADHD.

While these factors alone do not cause ADHD, they can contribute to the overall risk when combined with genetic predispositions and neurobiological factors.

Psychosocial

Psychosocial factors, such as family dynamics, parenting styles, and early life experiences, can impact the development and expression of ADHD symptoms.

While these factors do not directly cause ADHD, they can exacerbate or moderate the severity of symptoms.

For instance, inconsistent parenting or high levels of family stress may intensify ADHD symptoms or make them more challenging to manage.

On the other hand, a supportive and structured home environment can help mitigate symptoms and promote better overall functioning.