The Connection Between ADHD And Autism

Reviewed by Lauren Guilbeault

Published 06/24/2022

People often suspect attention deficit hyperactivity disorder (ADHD) when someone cannot focus on tasks, has trouble sitting still, or cannot make and sustain eye contact. These symptoms are identical to what most people know about the common neurodevelopmental disorder ADHD. Even many physicians tend to lean towards that diagnosis. However, ADHD might not be the only issue. Before making a diagnosis of ADHD, it might help understand the connection between autism and ADHD and how easy it is to confuse them.

ADHD And Autism

ADHD is a common neurodevelopmental condition that usually affects children. About 9.4% of children in the United States between ages two and 17 have an ADHD diagnosis. Three forms of ADHD are known: predominantly inattentive, predominantly hyperactive-impulsive, and a combination of the two. The combined form of ADHD is the most common. The average age of diagnosis is seven years, and boys are more affected by the condition than girls, although it could be how it presents itself.

Autism spectrum disorder (ASD) is another common childhood condition. It is a group of complex disorders that affect development, behavior, and communication. Approximately one in 68 children in the U.S. has an ASD diagnosis. Boys are more likely to get a diagnosis than girls.

Up until a few years ago, the American Psychiatric Association’s diagnostic manual stated that the two conditions occur independently of each other. It was in 2013, with the introduction of the current Diagnostic and Statistical Manual of Mental Disorders” (DSM-5), that a dual diagnosis became allowed. However, autism and ADHD usually overlap. About 30%-80% of children with autism also fit the criteria for ADHD, and equally, 20%-50% percent of children with ADHD for autism. Considering the overlap level, scientists are starting to consider the connection between the two conditions and search for common biological origins.

One study proposed that ADHD and autism are different indicators of a single disorder with several subtypes, each with a unique time of onset, a combination of behaviors, and progressions. With this proposition, ADHD can manifest without the indicators of autism, but autism can occur with the signs of ADHD and other conditions. This might be the reason for the question, “Is ADHD on the autism spectrum?”

As interesting as the ‘single-condition’ proposition might be, the evidence is not entirely conclusive. Many genetic studies agree with the opinion of some shared contributing factors between autism and ADHD. However, imaging studies comparing brain structures and connections have produced a mind-boggling mix of differences and similarities. Also, some behavioral research has suggested the chances that seemingly similar features hide unique underlying mechanisms. For instance, inattention in someone with autism might cause sensory overload, and noticeable social issues in someone with ADHD may show impulsivity.

However, knowledge of the connection between the two conditions can improve treatment methods, which is crucial. People who exhibit traits that show both ADHD and autism diagnosis usually face a more serious challenge than people with a single diagnosis. They may suffer a higher disruption of adaptive functions, which describes self-care and daily living skills and other social and cognitive problems.

The Similarities Between ADHD And Autism

In the early stages of the condition, it is easy for Autism and ADHD to be confused. Children with the conditions may have trouble expressing themselves or focusing. The major criteria for diagnosing the conditions are still unique in the DSM-5: social communication disorder and restricted and recurrent behaviors for autism, inattention or hyperactivity, and impulsivity, or both for ADHD. The two conditions affect the central nervous system, which controls memory, movement, language, social and focusing skills. Therefore, both conditions can delay speech, keen sensory responses, defiant attitudes, and issues with controlling emotions and challenges with planning and constraining behavior.

The strongest support for similar origins is traced back to studies of families and twins, which shows that family members of people with either disorder are more likely to have both. For example, according to a study in 2014, women with ADHD stand at six times more likely to have ADHD and carry more than twice the risk of having autism compared with the rest of the population.

Another study evaluated the risks on the opposite side. Looking at the medical data from almost two million people, the study discovered that people with autism and their extended family members are at a higher risk of ADHD. As expected for genetic conditions, ADHD risks are higher with identical twins of patients with autism and increases even in cousins. The cousins' increased susceptibility backs the idea of a genetic link between the two disorders – since cousins are usually more genetically similar than non-relatives but have fewer chances than twins to have been exposed to the same environmental factors during development. These results show that the conditions share certain genetic risk factors.

Although ADHD and ASD can occur together in adults, the combination is not as widespread as it is in children. While ASD is regarded as a lifelong condition, long-term studies have discovered that only one-third or two-thirds of children with ADHD have symptoms that last into adulthood.

The Differences Between ADHD And Autism

Many children receive their first diagnosis of ADHD when they begin preschool or kindergarten because their behavior is unlike other children. ADHD can make children restless at all times, act impulsively, or struggle with paying attention. However, some children's signs may be different, like focusing on one object and not wanting to play with something else.

For some children with autism, the signs are apparent before they clock two. For others, the signs of ASD may not be noticed until they reach school age and their social traits are distinct from other children. Children with autism usually avoid eye contact and often refuse to play or engage with others. Their communication skills may develop slowly or not at all. They may obsess with food textures or make repeated movements, usually with their hands and fingers.

Specific Behaviors

Usually, patients with ADHD struggle to focus on a single task or activity. They may get distracted easily. It is difficult for children with ADHD to finish a task before skipping to another, and they are usually physically unable to stay in one position. however, some children with ADHD may be so engrossed in a topic or task that they “hyperfocus.” Although focusing on one task might be a good thing, it may mean that the child struggles to shift their attention to other tasks when instructed.

Children with autism are more likely to stay overfocused, unable to change their focus to another task. Their routines are usually inflexible and have low or zero tolerance to change. This may mean going through the same path and taking the same food every day. Some of them have high sensitivity to noise, light, touch, pain, smell, or taste or develop strong interests. They may create food preferences based on texture or color and may make signals like repeated hand movements. This powerful concentration means that people with autism are usually able to recollect detailed facts for long periods and may be excellent at science, math, art, and music.

Watch the child’s attentiveness. Those with autism find it hard to focus on things they dislike, such as puzzles or reading a book, instead focusing on the things they prefer. Those with ADHD dislike and avoid tasks that require concentration.

You should also check how the child is learning communication skills. While the two conditions cause problems with interaction, those with autism have a lower social awareness of people around them. They usually struggle to articulate their thoughts and feelings and may not point to something that explains their speech. They also struggle to make eye contact.

On the other hand, a child with ADHD may talk a lot. They may likely disrupt someone else’s speech in an attempt to try to keep the conversation unilateral. Also, some kids with autism may speak non-stop about a subject they find interesting. An autistic person prefers order and repetition, but those with ADHD do not, even if it is helpful.

Getting Appropriate Treatment

If you suspect your child has ADHD or autism, the first step to getting the correct treatment is getting an accurate diagnosis. This may mean consulting a behavior disorder specialist. It is hard to diagnose the two conditions, so you can start with the pediatrician, who may provide a referral to a specialist—many general practitioners and pediatrician lack specialized training to decipher the combination of symptoms. The best medical provider for someone with ADHD and ASD is a doctor who has experience treating the two conditions.

To diagnose ADHD, the medical professional will check for behavioral patterns over time. They will also request feedback from parents, teachers, and other caregivers. They also need to eliminate the possible underlying conditions that may cause the symptoms and complicate the treatment plan. It will start with filling questionnaires about the person, usually about behaviors that began early. Additional tests and tools may include surveys, checklist, interviews, and observed activities.

Treatment for the symptoms of ADHD can also help manage autism symptoms. Behavioral therapy is a potential treatment for ADHD and is suggested as the first treatment for those below age six. For children above six years, behavioral therapy may include medications. Different forms of therapy, including sensory integration, speech, and occupational, can help kids speak and interact better. Drugs do not provide a cure but can make dealing with symptoms (like inattention and hyperactivity) easier.

The behavioral techniques that the specialist will teach the patient may also reduce the symptoms of ASD. Therefore, receiving proper diagnosis and treatment is important. The medical professional may have to try different treatment alternatives before finding the most effective option. Multiple treatment options may be combined.

The Bottom Line

There is no universal way to deal with ADHD or Autism. Usually, the symptoms and treatment may change as the child grows older. Scientists are still studying the connection between the two disorders. Studies may provide more information about the origins of the condition, and patients may have access to more treatment options. You can take an assessment test for ADHD here.