Diseases and Disorders

Attention Deficit Hyperactivity Disorder (ADHD): An Overview

Annie Pan


Attention deficit hyperactivity disorder (ADHD) is a chronic condition marked by persistent inattention, hyperactivity, and sometimes impulsivity [1]. To this day, between 5.29% - 7.1% of children and adolescents as well as 3.4% of adults suffer from ADHD worldwide [2]. There are over 3 million cases of ADHD each year, and ADHD has become an ongoing problem for kids and adults [3]. Throughout this article, we will look at the causes, symptoms, and solutions to ADHD.


Causes and Risk Factors

ADHD is one of the most prevalent disorders that appear during childhood. Research conducted at the National Institute of Mental Health (NIMH) and the National Institute of Health (NIH) has suggested that ADHD may be caused by interactions between genetic factors and environmental or non-genetic factors [1].

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Figure 1. A chart of all risk factors associated with ADHD [7].

Like many other illnesses, a number of factors may contribute to ADHD, such as genetics, cigarette smoking and alcohol/drug use during childbirth, exposure to environmental toxins (e.g. lead) at a young age, and brain injuries [1]. Research suggests that there is a possible correlation between ADHD and pesticides. A 2010 study in Pediatrics found that children with higher urine levels of organophosphate, a pesticide used on produce, had higher ADHD rates [4]. Another 2010 study showed that women with higher urine levels of organophosphate were more likely to have a child with ADHD. Fetal exposure to alcohol has also demonstrated a strong correlation between ADHD and drug/alcohol abuse [4][5]. Children exposed to tobacco smoke prenatally are 2.4 times as likely to have ADHD as those who are not. But one of the biggest risk factors that lead to children developing ADHD is lead. A 2009 study found that children with ADHD tend to have higher blood lead levels than other kids. Because of lead’s toxicity, it can damage developing brain tissues and have effects on a child’s behavior [4]. Studies have shown that families with a history of ADHD are more prone to inherit the disorder. Thus, genes have been proven to play a huge role in inheriting ADHD.

There have been many suspicions over sugar being a risk factor for ADHD, but no reliable research has proven that there is a correlation between the two. Another popular belief is that allergies and sensitivities cause ADHD, but research has failed to prove the idea that diet plays a large role in the development of ADHD [4][5]. As more resources and money are being allocated towards research, researchers have the potential to gain more understanding about ADHD.



According to the Mayo Clinic, “The primary features of attention-deficit/hyperactivity disorder include inattention and hyperactive-impulsive behavior. ADHD symptoms start before age 12, and in some children, they're noticeable as early as 3 years of age. ADHD symptoms can be mild, moderate or severe, and they may continue into adulthood.” Because of the varying effects of ADHD, afflicted individuals may need to seek varying treatments depending on the severity of their symptoms. ADHD occurs more often in males than in females, and behaviors can be different in boys and girls. For example, boys may be more hyperactive and girls may tend to be quietly inattentive. There are three subtypes of ADHD: predominantly inattentive, predominantly hyperactive-impulsive, and combined [3, 5]. The predominantly inattentive subtype occurs when the majority of the symptoms fall under being inattentive, while the predominantly hyperactive-impulsive subtype occurs when the majority of the symptoms fall under being hyperactive. The combined subtype is a mix between hyperactive and inattentive and is the most common in the US [5].

The most noticeable symptoms of ADHD is inattention, hyperactivity, and impulsivity. Children that have ADHD may be easily distracted, have trouble paying attention, fidget, and be very interruptive. They may struggle to complete activities quietly and appear to not listen even when spoken directly to [1, 5]. Symptoms can cause children to be unable to express their feelings properly, learn subjects, and pay attention to people talking to them. These symptoms can negatively impact children in regard to their school, home, and social life [3, 5].

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Figure 2. A chart of all the common symptoms associated with ADHD [8].



Though there is no definite cure for ADHD, there are types of therapies and medications that can be taken to reduce symptoms. For many people, ADHD medications reduce hyperactivity and impulsivity, improving their ability to focus, work, and learn. Some medications offered to ADHD patients are stimulants. Although it may seem unusual to treat ADHD with a medication that is considered a stimulant, it is effective. Many researchers think that stimulants are effective because the medication increases the brain chemical dopamine, which plays an essential role in thinking and attention. Non-stimulants can also be offered. Doctors may prescribe a non-stimulant if a person had bothersome side effects from stimulants, if a stimulant was not effective, or in combination with a stimulant to increase effectiveness. Two examples of non-stimulant medications include atomoxetine and guanfacine. Although antidepressants are not approved by the U.S. Food and Drug Administration (FDA) specifically for the treatment of ADHD, antidepressants are sometimes used to treat adults with ADHD. Older antidepressants, which are called tricyclics, sometimes are used because they, like stimulants, affect the brain chemicals norepinephrine and dopamine [1, 5]. There are also different types of therapies to aid individuals afflicted with ADHD. Parents may want to take their children to behavioral therapy and social skills group if they have ADHD [6]. There are many treatments and medications available to those diagnosed with ADHD. Though there is still no cure for ADHD, over time, ADHD researchers may discover a cure and end the widespread threat of ADHD to both children and adults once and for all.


  1. “Attention-Deficit/Hyperactivity Disorder (ADHD): The Basics.” National Institute of Mental Health, U.S. Department of Health and Human Services, www.nimh.nih.gov/health/publications/attention-deficit-hyperactivity-disorder-adhd-the-basics/index.shtml. Retrieved; 2/12/2019.

  2. “ADHD Epidemiology.” ADHD Institute, adhd-institute.com/burden-of-adhd/epidemiology/. Retrieved; 2/12/2019

  3. Rodak's Hematology: Clinical Principles and Applications - Google Search, g.co/kgs/5v7et7. Retrieved; 2/12/2019

  4. “What Causes ADHD? 12 Myths and Facts.” Health.com, www.health.com/health/gallery/0,,20441463,00.html?slide=120342#120342. Retrieved; 2/12/2019

  5. “Attention-Deficit/Hyperactivity Disorder (ADHD) in Children.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 16 Aug. 2017, www.mayoclinic.org/diseases-conditions/adhd/symptoms-causes/syc-20350889. Retrieved; 2/12/2019

  6. Team, Understood. “Treatment for Kids With ADHD.” Understood.org, www.understood.org/en/learning-attention-issues/treatments-approaches/treatment-options/treatment-for-kids-with-adhd. Retrieved; 2/12/2019

  7. “Pre- and Perinatal Risk Factors for #ADHD | ADHD | Pinterest | ADHD, Adhd Treatment and Adult Adhd.” Pinterest, Pinterest, www.pinterest.com/pin/495466396475501364/ Retrieved; 2/24/2019

  8. “3 ADHD Subtypes: Inattentive, Hyperactive/Impulsive and Combination.” Bonnie Terry Learning, 5 Oct. 2016, bonnieterrylearning.com/blog/suspect-adhd-diagnosed-with-adhd-adhd-symptoms/ Retrieved; 2/24/2019

Annie Pan

Annie Pan

Hi, I'm student at Ladue Horton Watkins High School who enjoys reading books. Have a good day!