ATTENTION DEFICIT HYPERACTIVITY DISORDER IN CHILDREN AND YOUTH WITH CONGENITAL HEART DISEASE- PART I
PART I: What is ADHD and What Does It Look Like in Children with and without CHD
David D. Schwartz PhD ABPP
Neuropsychologist, Texas Children’s Hospital
Associate Professor of Pediatrics, Baylor College of Medicine
Katherine Cutitta PhD
Psychologist, Texas Children’s Hospital
Assistant Professor of Pediatrics, Baylor College of Medicine
Background
Children with congenital heart disease (CHD) are more likely to develop Attention Deficit Hyperactivity Disorder (ADHD) than their peers. One recent study at Texas Children’s Hospital found that children with CHD (regardless of severity) were more than twice as likely to develop ADHD compared to all other patients. Other studies have shown that roughly 30% of children with more complex CHD have significant attention problems and/or hyperactive/impulsive behavior. In Part I of this Practitioner’s Post, we describe the core symptoms of ADHD and place them in the context of a broader model of self-regulation and self-control, and review the etiology (causes) of ADHD with a focus on children with CHD. In Part II, we explain what to do if you think your child with CHD also has ADHD, with a focus on evidence-based assessment and effective treatment and management strategies.
PART I: What is ADHD and What Does It Look Like in Children with and without CHD
ADHD is one of the most common neurodevelopmental disorders, affecting roughly 1 in 10 school-age children and adolescents. It is characterized by difficulties with focus and paying attention, hyperactive or restless behavior, and a tendency to act without thinking (impulsivity). People with ADHD often have more difficulty waiting, may struggle to motivate themselves to complete boring or demanding tasks, and can find it challenging to manage their time and stay organized. At the same time, ADHD may be associated with positive characteristics including a high energy level, creativity, and an ability to hyper-focus on tasks perceived to be especially interesting. People with ADHD can be successful in their lives, but to do so they often need support and accommodation.
ADHD is defined based on symptoms—there is no blood test, and it cannot be diagnosed based on a brain scan or other physiological measure. Diagnosis is based on the clinical history (usually taken by a pediatrician or psychologist) and parent and teacher ratings on standard behavioral questionnaires. The clinician will also rule-out alternative explanations for the symptom presentation, and to screen for comorbid conditions such as learning disabilities, behavioral disorders, anxiety, and depressive disorders.
To meet criteria for an ADHD diagnosis, the child has to show symptoms of inattention and/or hyperactive/impulsive behavior for at least 6 months in at least two settings.
Children with inattention have problems focusing and paying attention, especially on tasks that they find boring or mentally demanding; they may also get distracted more easily, and have difficulty keeping their mind on one topic.
Children with hyperactivity may be overactive and have difficulty staying still; they may act impulsively, without thinking through consequences first; and they may have difficulty with waiting, and choose immediate rewards rather than wait for something potentially better.
There are three subtypes of ADHD. Children who only show attention problems but are not hyperactive are considered to have the Predominantly Inattentive Presentation of ADHD (which used to be called ADD). Children who are hyperactive without obvious attention problems are considered to have the Predominantly Hyperactive-Impulsive Presentation, and children who have both attention problems and hyperactivity are considered to have the Combined Presentation (this is the most common presentation). It is important to keep in mind that the symptoms by themselves do not warrant a diagnosis of ADHD unless they also cause impairment and have a significant impact on the person’s daily life.
An additional criterion for diagnosis is that symptoms have to have been present before age 12. However, a kind of secondary or acquired ADHD has been recognized as an outcome of brain injury that can occur at any age. For example, an older adolescent who has a stroke after heart transplant may develop attention problems that meet all of the other criteria for ADHD except for age of onset. While there is some disagreement among professionals about whether a diagnosis of ADHD can be given if symptoms first arose after age 12, many still find a diagnosis useful in these cases, as it can help guide treatment interventions.
For more information about ADHD, click here and here.
ADHD and Executive Functioning
ADHD is associated with deficits in executive functioning, which refers to a set of abilities involved in controlling and regulating your own behavior, either in response to what’s happening in your immediate environment, or in the service of longer-term goals. There are different models of executive functioning, but most include three core abilities:
Inhibition – stopping an initial response or reaction, which gives you time to think about alternatives. For example, a child may inhibit himself from grabbing a cookie and ask instead, or from blurting out an answer in class and instead raise her hand.
Working memory – the ability to hold information in mind, often while using it in some way. An example might be figuring out in your head how much change you should get back from a purchase, or weighing different responses to a problem in your mind.
Shifting (or “mental flexibility”) – the ability to shift attention from one thing to another, change tasks, or choose an alternative response. Examples include shifting attention from a video game to get washed up for dinner, or changing your approach when something you’re doing isn’t working.
People with ADHD typically show deficits in all three core executive functions. They have difficulty inhibiting behaviors, keeping information in mind without getting distracted, and shifting to a different idea, task, or response (or, alternatively, they may shift too frequently, and have difficulty staying on one topic). As a result, they may also have difficulty with more complex executive functions—such as planning, problem-solving, and decision-making—which rely on these three basic abilities.
Some researchers have argued that ADHD can be thought of as an executive function deficit disorder, a disorder in self-regulation and self-control. From this point of view, attention problems can be thought of as a deficit in controlling what you pay attention to.
Almost no one has difficulty paying attention to things that are interesting and “capture your attention”—the problem is when you have to make yourself focus on something boring or mentally demanding. A common example is playing video-games.
Parents will often say that their child can’t have ADHD because they can sit and play video-games for hours, but the real problem is that they can’t easily stop playing and shift to a different task—which is why they may have a huge tantrum if made to stop. Similarly, hyperactivity can be thought of as a difficulty with controlling excess movement, and impulsivity with controlling an impulse to say or do something without thinking about it first.
Difficulty with controlling emotional responses is less often talked about, but may be just as common in ADHD as deficits in attentional and behavioral control. Everyone experiences a surge in emotion when frustrated, excited, or upset, but then a counter-regulatory response usually kicks in to calm us enough to pause and consider how best to respond. Individuals with ADHD often have difficulty with putting the brakes on their emotional reactions. They tend to show poor frustration tolerance, and are more impatient, excitable, and quick to anger. They may also have more difficulty distracting themselves from whatever upset them, and shifting their attention to something else.
Finally, we sometimes also see motivational deficits in children and youth with ADHD. As noted, people with ADHD tend to be more strongly motivated by immediate rewards and have difficulty with deferred gratification, and they find it more difficult to “force themselves” to complete boring or mentally-demanding tasks. This is why using immediate rewards can be especially effective for children with ADHD. It is also why these children may have an especially hard time shifting attention away from video games, which actively engage the reward circuits in the brain. It is important to understand that such motivational deficits are likely brain-based and do not reflect “laziness,” defiance, or a lack of a desire to please others.
How can ADHD affect my child’s daily life?
ADHD can have pervasive effects on a person’s life. School problems are common. Children with ADHD may daydream in class, get distracted easily, and have difficulty staying focused on work (especially mentally-demanding work). Younger children may exhibit disruptive behavior in the classroom (or at home), resulting in a pattern where they are frequently reprimanded and in trouble, which can in turn result in a negative self-image as a “trouble-maker” or “bad kid.” They may also have more difficulty making and keeping friends due to inattention to social cues, immature or overly silly behavior, or difficulty keeping their hands to themselves.
Adolescents are expected to be responsible for staying on top of their schoolwork, managing their time, and meeting due dates, all of which may be more challenging due to the organizational and executive difficulties that come with ADHD. Teens with ADHD are also more prone to impulsive, risk-taking, and rule-breaking behavior. They are more likely to become parents at an earlier age, have more driving accidents, and may “self medicate” with alcohol or other drugs. Adults with ADHD may have more difficulties sticking with a job and maintaining long-term relationships.
Children with chronic illnesses like CHD often have to follow medical regimens such as taking medication at a certain time each day, which become their responsibility as they get older. Forgetfulness, disorganization, and inattention can all affect a youth’s ability to stay on top of a medical regimen, making parental oversight especially important.
So what causes ADHD, and how is it linked to CHD?
ADHD is considered a neurodevelopmental disorder, meaning most people are born with it, show symptoms in childhood, and may have delays in their development as a result. ADHD is highly heritable, which means it runs in families due to genes that get passed down from parent to child. If you have ADHD, your child is more likely to have it too.
Prenatal factors can also play a role in the development of ADHD. For example, fetal exposure to alcohol, nicotine, and other substances increases the risk that the child will have ADHD. In addition, children born prematurely also have a greater risk of ADHD. The basic idea is that, early in life, the developing brain is especially vulnerable to insult and injury, and one of the most common outcomes of early insult is ADHD.
It is this early vulnerability that places children with CHD at increased risk for ADHD. Congenital heart defects can result in reduced blood flow (ischemia) and reduced oxygen (hypoxemia) to the brain, which can have an effect on how the brain develops prenatally and in early childhood. Children with complex CHD often show immature brain development at birth, with reductions in both cerebral gray and white matter; and these differences are associated with increased risk for neurodevelopmental disability. In fact, children with CHD closely resemble children born prematurely in terms of their neurodevelopmental outcomes.
Cardiac surgeries, especially in the first few years of life, and associated procedures such as being placed on cardiopulmonary bypass or ECMO, can also affect how the brain develops, and add to the risk for ADHD symptoms. Children with cyanotic heart lesions, or with medical co-morbidities, are also at higher risk.
One of the brain regions most vulnerable to early insult are the frontal lobes, which take up about 1/3 of the total surface area of the brain. The largest part of the frontal lobe is the prefrontal cortex, which is the brain region most closely involved in executive functioning. It therefore isn’t surprising that executive dysfunction is among the most common (if not the most common) neurocognitive deficits seen in people with CHD.
Changes in symptoms over time
While most people with ADHD do not “grow out of” the disorder, the symptom presentation can change as children get older. Hyperactive behaviors are most common in younger children, and may moderate over time, especially as the child enters adolescence. Attention problems typically become more evident as children reach grade-school age and expectations for focus and concentration increase. While impulsivity often remains evident throughout development, it may become a different kind of problem in adolescence, as youth begin to have greater freedom from their parents, start to drive, and may be faced with risky choices such as whether to drink alcohol or use other substances, or to engage in unprotected sex. Teens may also begin to have more difficulty with self-esteem, anxiety, and depressed mood.
Children and youth with CHD may face a different kind of change in ADHD symptoms related to their heart disease. Chronic hypoxemia and heart failure may result in worsening attention over time. Complications of later-occurring heart surgeries, placement of ventricular assist devices, and transplant may also result in a worsening of symptoms. For children and youth with CHD, ADHD symptom surveillance is important, as is periodic re-evaluation every couple of years, or following any new significant cardiac event or surgery.
Dr. Katherine Cutitta
Katherine Cutitta, PhD, is an Assistant Professor at Baylor College of Medicine and serves as the dedicated clinical health psychologist for the Heart Center at Texas Children’s Hospital. She works with families and children with congenital heart disease, as well as adults with congenital heart disease to help improve quality of life and establish heart healthy habits with managing congenital heart disease.
Dr. David Schwartz
Dr. Schwartz is a pediatric neuropsychologist at Texas Children’s Hospital and Associate Professor of Pediatrics at Baylor College of Medicine. He has long worked with children, youth, and young adults with congenital heart disease. Dr. Schwartz currently conducts neuropsychological evaluations of patients seen through the Texas Children’s Hospital Cardiac Developmental Outcomes Program and Heart Transplant Program, and he has completed research on cognitive outcomes in adult survivors of CHD.