ADHD is a complex disorder, characterised by symptoms such as inattention, hyperactivity, and impulsivity. While extensive research has been conducted to understand the causes of ADHD, it remains a subject of ongoing study and debate.

This article aims to shed light on the current understanding of the causes of ADHD and explore the various factors contributing to its development.

Genetic Factors

One of the strongest pieces of evidence supporting a genetic component in ADHD is the higher likelihood of the disorder occurring in individuals with a family history of ADHD. Various studies have suggested that genetics plays a substantial role in the development of ADHD. 

It is estimated that genes are responsible for 75-91% of the variance in ADHD risk. Researchers have identified multiple candidate genes that are associated with ADHD, including those related to neurotransmitter regulation and neural development. 

However, no single “ADHD gene” has been definitively identified, and it’s more likely that the disorder results from a combination of multiple genetic factors.

Neurobiological Factors

ADHD is often linked to abnormalities in brain structure and function. Neuroimaging studies have shown that individuals with ADHD tend to have slightly smaller brain volumes, particularly in regions responsible for attention, impulse control, and executive function. Dysregulation of neurotransmitters, such as dopamine and norepinephrine, is also associated with ADHD.

These neurotransmitters play a vital role in cognitive functions, motivation, and emotional regulation. Dysfunctions in the brain’s reward system may contribute to the symptoms of impulsivity and inattention.

Environmental Factors

While genetic and neurobiological factors play a significant role, environmental factors can also contribute to the development of ADHD. Prenatal and early-life exposures can have a lasting impact: 

1. Prenatal Factors
   Exposure to certain prenatal factors, such as smoking during pregnancy, alcohol consumption, maternal stress, and exposure to environmental toxins like lead, may increase the risk of ADHD in children.
   
   
2. Low Birth Weight and Prematurity
   Children born with low birth weight or prematurely are at a higher risk of developing ADHD. The stress of an early birth and potential brain development issues may contribute to the disorder.
   
   
3. Postnatal Factors
   Postnatal factors, including early exposure to high levels of lead or other environmental toxins, can be a risk factor for ADHD. Additionally, childhood trauma, neglect, and adverse childhood experiences have been linked to an increased likelihood of developing ADHD.