Science hasn’t yet found the specific cause of ADHD, but as the research grows, we gather more clues. Researchers have identified several risk factors for developing it, including:
- Genetic factors
- Environmental factors
- Brain injuries
- Gender
Several twin and adoption studies, as well as brain studies, have linked specific genes to ADHD. It’s possible that this disorder may be genetic or dependent on brain structure.
Environmental factors have long been viewed as one of the most common causes of ADHD. Some external factors that can increase the risk of developing ADHD include:
- Smoking and drinking alcohol during pregnancy
- General exposure to nicotine and alcohol
- Low birth weight or premature birth
- Childhood diet and quantity of food additives consumed
- Exposure to lead
Another risk factor, brain injury, is one of the least common causes of ADHD. But it can happen. One study found that 62% of children treated for a traumatic brain injury developed ADHD.
Finally, gender plays a crucial role in ADHD diagnosis. Boys are much more likely to receive a diagnosis than girls. In a 2016 national survey, the CDC found that 12.9% of boys and 5.6% of girls have ADHD.
A long-suspected reason for this discrepancy is how society views gender. Girls who struggle with ADHD might be described as dreamy, sensitive, or immature. Teachers and parents tend to be more accepting of their symptoms, so girls have a tougher time getting a diagnosis.
Boys, on the other hand, show more obvious signs of ADHD. Parents and teachers quickly notice the symptoms because they are expressed outwardly. Acting out, being rude and impatient, and having too much energy are easy to spot signs.
These differences might explain why boys often receive a diagnosis at a younger age. Surveys show that boys are usually diagnosed around seven years old and girls at around twelve years old.
But even more commonly, girls don’t get a diagnosis at all. Research shows that over 75% of girls with inattention type ADHD aren’t even diagnosed!
