5 Top Theories about the Causes of ADHD

Boy with finger to his lips, sitting at a desk with a pencil and notebook.

Attention deficit hyperactivity disorder (ADHD) has become one of the most common childhood disorders that persist into adulthood, affecting about four percent of adults in the U.S. Many theories have been proposed over the years as to the causes of this disorder. Some have been rejected, while others require more research to be done.

Below are five of the most common theories about causes of ADHD:

1. Genetics

Too often people dismiss ADHD as the result of a poor diet high in sugar or bad parenting. Research has identified certain genetic abnormalities to be the cause of ADHD. It has been shown that the brains of children with ADHD develop differently from other children.

A study published in The Lancet reported that scientists at Cardiff University in Wales found children with ADHD more likely to have some small segments of their DNA either missing or duplicated.¹

According to the study, it identified significant overlap between these segments, known as copy number variants (CNVs) and genetic variants implicated in autism and schizophrenia, thus demonstrating supporting evidence that ADHD is a neurodevelopmental disorder.

2. Pesticides

Lead researcher in the study, Maryse Bouchard, Ph.D., explains how organophosphates are designed to have a toxic effect on the nervous system.² The pesticides interfere with a set of brain chemicals closely related to those involved in ADHD. According to the EPA, most people’s exposure to these pesticides comes through food (commercially grown fruit and vegetables), drinking water, and residential pesticide use. There are approximately 40 organophosphate pesticides registered with the U.S. Environmental Protection Agency (EPA).

3. Complications During Pregnancy

Studies have shown that complications during pregnancy can lead to ADHD.³ Complications that have been identified include high blood pressure during pregnancy, bleeding before the birth, extended pregnancy beyond the due date, long delivery time, and any complications affecting the baby’s oxygen supply during birth.

4. Cigarettes and Alcohol

Multiple studies have consistently shown that smoking during pregnancy is a perinatal factor in the incidence of ADHD.⁴ Researchers have found that children with ADHD are more likely to have a maternal history of smoking during pregnancy than healthy controls. Alcohol consumption has been a proposed risk factor in ADHD. Moreover, ADHD is often diagnosed in children with fetal alcohol syndrome and in children of alcoholics. Research indicates that children born to mothers who had abused alcohol throughout pregnancy had more behavioral and attention problems than children born to mothers who did not consume alcohol during pregnancy.⁵

5. Lead Exposure

Although U.S. governmental regulations have substantially reduced environmental exposure to lead by regulating automobile fuel and paint ingredients, children may continue to be exposed if they live in older homes and apartments, which contain older plumbing fixtures as well as lead-based paint still on walls and woodwork.Lead is found in a variety of things ranging from children’s jewelry and toys to certain foods, food containers, and certain cosmetics. Research suggests that chronic long-term low level exposure to lead is a cause of ADHD.⁶

The researchers discovered that children diagnosed with hyperactive and impulsive symptoms had slightly higher levels of lead in their blood compared with children who did not demonstrate these behaviors.

ADHD Is My Super Power and It Comes with Great Super Strength

by Alana Moore

PSN Link: https://amzn.to/3j11p5L

Sources:

First direct evidence that ADHD is a genetic disorder: Children with ADHD more likely to have missing or duplicated segments of DNA. ScienceDaily. 2010.

Attention-Deficit/Hyperactivity Disorder and Urinary Metabolites of Organophosphate Pesticides. Pediatrics. 2010.

ADHD and Pregnancy. The American Journal of Psychiatry. 2014.

Prenatal nicotine exposure during pregnancy results in adverse neurodevelopmental alterations and neurobehavioral deficits. Advances in Drug and Alcohol Research. 2023.

Fetal alcohol syndrome. MayoClinic. 2024.

Annual Reserach Review: Perspectives on progress in ADHD science – from characterization to cause. Journal of Child Psychology and Psychiatry. 2022.

Child with head in hands at a desk with schoolwork.

Understanding the Mental Skills Affected by ADD and ADHD (Part 1)

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Jennifer says:
August 14, 2015 at 7:22 am
There are only 2 items listed here. Where are the other 3?
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- Chantai Snellgrove says:
  August 15, 2015 at 11:46 am
  Hi Jennifer: Click on the continued reading link to read the rest of this article.
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Taylor Stout says:
April 26, 2017 at 6:22 pm
When was this article published?
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5 Top Theories about the Causes of ADHD

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