Update on ADHD

ATTENTION DEFICIT hyperactivity disorder (ADHD) is among the most common mental health diagnosis in children and adolescents. The U.S. Centers for Disease Control and Prevention (CDC) reports that nearly 12 percent of American children have a current ADHD diagnosis.¹

While many will find their symptoms ease as they enter adulthood, some six percent of adults are also presently diagnosed with ADHD in the U.S.² (Interestingly, many of them were diagnosed only after they became adults.)

With diagnosis rates in children rising rapidly — an increase of 33 percent from 1997 to 2008 — there is a growing focus on ADHD within the medical and mental health professions. While some therapists argue the leap in diagnosis rates is due to ADHD being overdiagnosed — categorizing normal childhood behavior as a disorder — a significant number of others believe it is in fact underdiagnosed, depriving children of critical treatment that could markedly improve their quality of life.³

The specific term “attention deficit hyperactivity disorder” is a relatively recent formal diagnosis, only being added to the Diagnostic and Statistical Manual of Mental Disorders (DSM) revised third edition in 1987. The first inclusion of this disorder under any name in the DSM (the standard reference for mental health professionals) was in the second edition in 1968 as “hyperkinetic reaction of childhood.” That was updated to attention deficit disorder (ADD) in the third edition in 1980, and then, as mentioned, to ADHD in 1987.

Yet, the first description of the symptoms associated with ADHD was likely by Scottish physician Alexander Crichton, who in his 1798 three-volume overview of mental health included a chapter titled “On Attention and Its Diseases.”⁴ However, modern researchers and clinicians point out that the symptoms he described are also present in other conditions such as epilepsy and metabolic dysfunction.

Subsequent developments in describing and then diagnosing ADHD include:

• German physician Heinrich Hoffmann published a series of illustrated children’s books in 1844, including a story about “Fidgety Phil.” In this book, a young boy at the dinner table exhibits symptoms consistent with a modern diagnosis of ADHD.
• In 1902, British physician George Frederic Still gave a lecture at the Royal College of Physicians of London on behavior he described as a “lack of moral control” that occurred “without general impairment of intellect and without physical disease.”
• Two German doctors in 1932 described what they called “hyperkinetic disease” in young children, in which they seemed incapable of sitting still for more than short periods of time.
• Five years later, U.S. physician Charles Bradley, in seeking to treat painful headaches in his patients following the use of pneumoencephalogram brain imaging, discovered that while benzedrine was ineffective in relieving their pain, it did ease symptoms of inattention in the classroom. This led to the eventual adoption of stimulants as a primary course of treating ADHD4 (alongside ongoing therapy to impart effective coping skills).

What is ADHD?

ADHD is classified as a neurodevelopmental disorder. It is actually a bit of an umbrella term, taking in two distinct sets of symptoms that often coexist. These are classified into three subtypes of ADHD:⁵

• Predominantly inattentive (ADHD-I): Patients struggle to focus on the task at hand, may be forgetful and are often unorganized. This diagnosis is what replaced the earlier ADD.
• Predominantly hyperactive-impulsive (ADHD-H): Patients struggle to stay still, and may be moving or climbing when not socially appropriate to do so. This is usually accompanied by poor impulse control, including excessive talking.
• Combined ADHD (ADHD-C): Patients exhibit symptoms of both of the other types; this is the most common ADHD diagnosis.

In ADHD patients, symptoms will interfere with their ability to function successfully in school, work or social settings.

While it was originally thought children would outgrow ADHD,⁶ today it is believed that is true for only fewer than half of patients. The manifestation of symptoms changes in adulthood — primarily in the hyperactivity component. While in children the hyperactivity component often results in actual physical activity, in adults it is more likely to be experienced as a feeling of restlessness.⁷

Researchers have also shown that untreated ADHD increases the risks of developing depression or an anxiety disorder, and is tied to an increased likelihood of suicide. It is also tied to higher rates of drug abuse, criminal behavior and even medical complications such as sleep disorders. Less dramatically, but nearly as harmful, are lower educational outcomes, poorer professional performance and difficulty managing personal finances.⁸

What Causes ADHD?

The underlying cause of ADHD is not fully understood. Researchers believe it is a combination of genetic predisposition and exposure to environmental factors, including injury, nutrition and social interactions.⁸

Some schools of psychology view the condition as wholly psychological. Psychoanalytic theory (Freudian psychology) holds that ADHD is the result of early parent-child interactions. Some psychoanalysts do acknowledge the biological component, but theorize that the negative early interactions affect the brain’s own physical development.³

On the other hand, evolutionary psychology teaches that ADHD is an orphaned trait that formerly bestowed survival benefits in an earlier environment, but is maladaptive to modern life.³

However, research has discovered that patients with ADHD have measurable differences in the structure of their brain compared to non-ADHD patients.⁹ While it is not understood how exactly this leads to ADHD, or whether everyone with these structural differences will develop ADHD, it is widely accepted that there is a connection.

In addition, it is known that ADHD runs in families. Recent research indicates there is no single gene tied to ADHD, but instead many different genes each contributing a small variation.¹⁰

Of particular note are genes tied to the regulation of neurotransmitters.¹¹

And, one recent study found a strong correlation (more than 40 percent) between post-viral fatigue syndrome or myalgic encephalomyelitis/chronic fatigue syndrome and ADHD.¹²

Diagnosing ADHD

Since there is no single test for ADHD, arriving at a diagnosis consists of cataloging symptoms and measuring them against the DSM criteria, while also ruling out other potential causes.

A diagnosis of ADHD requires that:

• Symptoms are developmentally inappropriate for the patient’s age
• Symptoms last longer than six months
• Symptoms manifest in at least two different settings
• Symptoms cause impairment in these settings
• Other possible causes of the symptoms have been ruled out

For children (under age 17), six of nine symptoms for ADHD-I or ADHD-H must be confirmed, while only five are required for a diagnosis in an adult. (Having three from one list and three from the other does not meet the criteria.) In all patients, no matter the age at the time of initial consultation with a physician or therapist, at least some of the ADHD symptoms must have begun before age 12.

Conditions such as bipolar disorder, autism spectrum disorder, oppositional defiant disorder and certain learning disabilities can present similar symptoms and should be considered before a final diagnosis is made.¹³

A physical examination should also be performed to rule out any potential physiological causes of symptoms such as a sleep disorder, thyroid issues, seizure disorders, diabetes and others.¹⁴

For children or adolescents, physicians or therapists should reach out to the patients’ teachers, coaches or other adults in their life to gain feedback about their behavior in these different settings.

The checklist of symptoms in the DSM-5 are broken up into ADHD-I and ADHD-H.

The nine criteria for ADHD-I are:¹⁵

• Does not pay attention to details or makes careless mistakes in schoolwork or with other activities
• Has difficulty sustaining attention on tasks at school or during play
• Does not seem to listen when spoken to directly
• Does not follow through on instructions or finish tasks
• Has difficulty organizing tasks and activities
• Avoids, dislikes or is reluctant to engage in tasks that require sustained mental effort over a long period of time
• Often loses things necessary for school tasks or activities
• Is easily distracted
• Is forgetful in daily activities

The nine ADHD-H criteria are:

• Often fidgets with hands or feet or squirms
• Often leaves seat in classroom or elsewhere
• Often runs about or climbs excessively where such activity is inappropriate
• Has difficulty playing quietly
• Often on the go, acting as if driven by a motor
• Often talks excessively
• Often blurts out answers before questions are completed
• Often has difficulty awaiting turn
• Often interrupts or intrudes on others

If patients meet six of nine criteria in both categories (five each for adults), then a combined ADHD diagnosis will be made.

Symptoms may present differently in adults than in children. ADHD-I may manifest by missing deadlines or forgetting meetings at work, or with difficulty paying attention during uninteresting meetings. ADHD-H may look like interrupting others, talking louder than appropriate or intruding on projects to which they’re not assigned.¹⁶

And, in children, symptoms may manifest more subtly in girls than in boys — which is likely at least partially responsible for 16 times as many boys as girls being diagnosed with ADHD. Among those who are diagnosed, girls are more likely to have ADHD-I, while boys are statistically more likely to have ADHD-H. Even within the same subtype, the behavior is likely to differ. Where boys might become physically aggressive, girls may exhibit verbal aggression. And, because inattentiveness isn’t as disruptive to a classroom setting, teachers may not think to talk to the parents about having the student tested.¹⁷

There is some evidence that cultural and sociological stereotypes may also be subconsciously affecting diagnosis in different populations, with white males more likely to receive an ADHD diagnosis than females¹⁸ or non-white males, even when presenting with identical symptoms.¹⁹ In many cases, Black males are diagnosed with conduct disorder even though they meet the diagnostic criteria for ADHD.³ There is a stereotype of a typical ADHD patient being a white boy, and that may unknowingly shape a clinician’s own expectations without any intent of bias.

In addition, with widespread access to ADHD criteria lists, parents of pediatric patients or adult patients themselves may have already self-diagnosed and have pressured a therapist for a formal diagnosis.¹⁴

Treating ADHD

ADHD in children is generally treated with a combination of behavior therapy and medications. The specifics will be based on the type of ADHD diagnosed, the age of the patient, the severity of the symptoms and any co-occurring medical or mental health conditions affecting the patient.

For patients younger than 6 years, CDC recommends training the parents in behavior management as the first course of action. This training helps parents create a stable routine and daily structure for the child, reducing the severity of symptoms. Research has shown parental training is just as effective as medication in young children, and the side effects of medication are often more pronounced in them.²⁰

Parent training is recommended through about age 12 years, at which point psychosocial therapy for the patient is advised, along with medication (if not already begun). Teens should meet with a therapist who will teach them about their condition and symptoms they’re experiencing, and then identify a couple of behaviors to work together to improve.²¹

Adult patients are most commonly referred for cognitive behavioral therapy (CBT). This focuses on teaching patients to be self-aware of their own behaviors, and allows them to intentionally change their actions to a desired behavior. There is also some research that shows a regular exercise program can help ease symptoms of ADHD.²² CBT has not proven effective in youth, however.

Medication can be prescribed for children who are at least 6 years old, and has proven to be effective in easing symptoms of a majority of patients. (Some medications can be prescribed as young as 4 years if symptoms are severe and therapy has proven ineffective.)

Two classes of medications are generally prescribed to treat ADHD, particularly in children: stimulants and non-stimulants.

The most widely prescribed ADHD drug is the stimulant methylphenidate (MPH), with the most popular brand name being Ritalin. This drug blocks the dopamine and norepinephrine reuptake transporters in the nervous system, which results in higher levels of those hormones that regulate how the brain works.²³ Long-term studies indicate MHP is effective not only in modifying behavior, but also in improving school learning outcomes, particularly in math.

Where Ritalin is a short-acting tablet (three to four hours), another MHP formula is sold under the brand name Concerta — which is an extended-release tablet that can last up to 12 hours. Ritalin can cause increased blood pressure and have negative interactions with blood pressure and other heart medications, making it less appropriate for many adult patients.

Another stimulant, dexmethylphenidate (brand name Focalin), comes in both short-acting and extended-release versions.

Several amphetamines are also approved by the U.S. Food and Drug Administration (FDA) for treating ADHD. These include Adderall, lisdexamfetamine (Vyvanse) and dextroamphetamine (Dexedrine, Zenzedi, ProCentra). These work similarly to MHP, resulting in elevated levels of dopamine and norepinephrine.

Non-stimulants typically take longer to be effective than stimulants, but have different side effects. For patients who suffer sleep disruption or weight loss from stimulants, this second class may be more tolerable.

Two types of non-stimulants are prescribed to treat ADHD: selective norepinephrine reuptake inhibitors (NRIs) and alpha-2 adrenergic agonists.

NRIs — which include atomoxetine (Strattera) and viloxazine (Qelbree) — work somewhat similarly to MHP in that they block the brain from reabsorbing norepinephrine, resulting in elevated levels. Atomoxetine is associated with an increased rick of suicidal ideation, and carries a warning to that effect on its packaging.

Alpha-2 adrenergic agonists include brand names clonidine (Catapres, Kapvay, Onyda XR) and guanfacine (Intuniv). These drugs work by targeting specific receptors in the frontal cortex, which improves impulse control and attention.²⁴

Also, patients can have other conditions in addition to ADHD. As many as 70 percent of ADHD patients have co-existing psychiatric disorders, including anxiety and depression. These will also need to be treated in parallel with the ADHD.²³

Ongoing Research Into ADHD

As one of the most common disorders in children, ADHD understandably is the subject of numerous ongoing research studies. FDA’s clinicaltrials.gov site lists just under 2,000 recent or current trials for ADHD. These range from the physiology of ADHD to the genetics thought to underlie it, to potential new drugs that may effectively treat it with fewer side effects, as well as using existing FDA-approved drugs off-label to treat ADHD.

Primary research is attempting to learn the specific causes of the condition. When that is more fully understood, more effective treatments can likely be developed.

In the meantime, as with many chronic medical conditions, a growing body of evidence suggests inflammation plays a role in ADHD.²⁵ One such recent study suggested anti-inflammatory drugs should be explored as a potential treatment for ADHD.²⁶ 

And, another recent study out of Washington University in St. Louis, Mo., found the stimulant drugs actually work by stimulating the brain’s reward center, and by increasing wakefulness.²⁷ If true, this changes our understanding of how these drugs work, and suggests another approach to devising new drugs.

Transcranial direct current stimulation, in which very low-level electrical currents are delivered to the brain, was studied at Bradley Hospital in Rhode Island a few years ago. Previous research had found subjects who underwent this noninvasive procedure exhibited improved impulse control.²⁸

For the foreseeable future, however, physicians and therapists will continue to treat ADHD patients with an existing array of options that are safe and generally effective.