The ADHD Brain vs. the Non-ADHD Brain

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental conditions diagnosed in children. This means there are differences in the ADHD brain that affect development.

Children with ADHD may have difficulty paying attention to parents and teachers, following rules and staying on task, and behaving in appropriate ways. They may seem overly active, disruptive, and impulsive. Symptoms may change throughout their lifetime, but adult ADHD does exist and can cause difficulties in relationships, work, and everyday life. 

This article will detail the differences between the ADHD brain and a neurotypical brain (without ADHD), as well as provide information on treatment.

Differences Between the ADHD Brain and the Neurotypical Brain

ADHD is a complex condition associated with detectable differences in the structure and function of specific brain regions. Understanding these differences validates the disorder and help reduce stigma associated with ADHD. 

Brain Structures

Several structural differences have been identified in the ADHD brain compared to the non-ADHD brain. A 2018 review of ADHD-patient brain scans demonstrated smaller brain sizes in those with ADHD. Brain size is not, however, linked to intelligence. The brain volume size was also smaller in five subcortical areas (located deep within the brain). The differences were greater in children and less prominent in adults.

Here are some differences in brain structures in people with ADHD:

• Prefrontal cortex and frontal cortex: Located at the front of the brain, the prefrontal and frontal cortex are responsible for high-level executive functioning. Executive functioning is associated with organizing, planning, and maintaining attention. Brain structure and function differences in this region are associated with difficulties in developing and displaying executive functioning skills. 
• Limbic system: Deep within the brain, the limbic system is responsible for emotional regulation. This includes impulse control. Differences in this area are associated with difficulties in self-regulating. Examples include having a hard time being quiet or controlling emotions. One 2017 study demonstrated that people with ADHD have dysfunction in the limbic system.
• Basal ganglia: The basal ganglia is a group of structures associated with processing information. It receives information from other brain areas and relays the messages back and forth from the motor center. It’s linked to motion planning, which is characterized as knowing what steps to take and in what order. Dysfunctional information processing has been shown in the circuit areas of people with ADHD. Dysfunction doesn’t also mean deficient, though. Resting-state MRIs (magnetic resonance imaging scans) suggest people with ADHD may actually have an increased level of functional connectivity in certain brain regions than those without ADHD.
  
• Reticular activating system (RAS): The RAS is a network of neurons in the brain stem that are involved in filtering information or organizing what’s important and what's not. While it sounds simple, your brain has to filter through a lot of information. Dysfunction in the area is therefore associated with a variety of ADHD symptoms like inattention, impulsivity, and/or hyperactivity.

Brain Activity and Function

Brain regions aren’t operating in isolation. This means dysfunction in one area may result in dysfunction in other areas. For example, increased brain activity (functional connectivity) in certain brain areas has been associated with more severe hyperactivity symptoms in people with ADHD.

With time, people with ADHD may show improvements in these areas, as the brain matures and as they develop or improve coping skills. This is one explanation why childhood ADHD doesn’t always follow into adulthood or why symptoms may be less severe as a person enters adulthood.

Brain Chemistry

Different neurotransmitter activity and functioning have also been demonstrated in the ADHD brain. Neurotransmitters are chemical messengers, or pieces of information being sent to different brain regions. 

Dopamine and norepinephrine are two neurotransmitters associated with the ADHD brain, as such:

• Dopamine is most known for its role in reward and motivation.
• Norepinephrine is associated with many important functions, including mood regulation, energy levels, and focus. 

Diagnosing ADHD and Outlook

A psychologist, or psychiatrist will diagnose ADHD based on symptoms as they relate to the criteria listed in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Assessing symptoms typically includes a detailed patient/parent interview, medical history review, and tests to measure attention, distractibility, and memory recall.

Brain Imaging and ADHD

Researchers use several brain imaging techniques to examine structure, function, and activity in the ADHD brain. These include:

• Functional magnetic resonance imaging (fMRI)
• Positron-emission tomography (PET)
• Single-photon emission computed tomography (SPECT)

Gender and ADHD

The role of gender in ADHD diagnosis is important as girls and women have been underdiagnosed and even undiagnosed due to gender bias in testing and criteria. This trend has led to girls incorrectly receiving anxiety and depression diagnoses since girls may appear inattentive or process their emotions internally more so than boys. Boys tend to demonstrate hyperactivity symptoms more so than girls.

One review of 73 studies suggests that gender differences are at least partially attributed to methodological artifacts (such as the way testing for ADHD has been conducted) or social and cultural influences (such as preconceived notions about how males and females “should” behave), rather than fundamental differences in how ADHD is expressed in men and women.

Treatment for ADHD

ADHD is often treated with medications and/or lifestyle changes. While lifestyle changes usually cannot treat ADHD on their own, they can help relieve some symptoms of ADHD.

ADHD Medication

In children 6 years and older, medication is the first-choice treatment for ADHD. Stimulant medications are the gold standard. Between 70%–80% of children with ADHD have fewer ADHD symptoms when taking these fast-acting medications, according to the Centers for Disease Control and Prevention (CDC). Non-stimulant medications are also an option, although they don't act as fast.

Lifestyle Changes

Lifestyle changes may also be helpful, particularly in children or teens still developing habits and coping skills. 

Lifestyle changes known to be helpful for people with ADHD include:

• Building a network of ADHD-aware or ADHD-friendly people 
• Improving sleep habits, which include sticking to a regular sleep schedule
• Exercising, which also helps reduce stress
• Eating a healthy diet that includes enough protein to maintain stable energy levels
• Creating an ADHD-positive environment free of distractions for break or study times 

Outlook

There is no cure for ADHD, but it can be managed with the right treatment. The best treatment for one person may not be the best for another, though. If you’re ready to discuss with your doctor, know that this will be an ongoing conversation. Since there are many options, finding what works for you or your child may take some trial and error but can improve life quality. 

Summary

Brain differences have been demonstrated in people with ADHD vs. people without ADHD. The complexity of the brain and the disorder make it impossible to say any one difference over the other is the “cause” of ADHD. It’s more likely a combination of many factors working together. Regardless, treatment is available and can help reduce symptoms and improve overall everyday functioning. 

A Word From Verywell 

If you or someone you love has been diagnosed with ADHD, please know that it’s still entirely possible to live a satisfying and successful life. If you’ve been wondering if you have ADHD, particularly if you’re a female with other diagnoses, you may want to consider speaking with your doctor about symptoms you're experiencing. With the right diagnosis, treatment, and support, you may find your life becoming much easier.