Attention deficit hyperactivity disorder

00:00 / 00:00



Attention deficit hyperactivity disorder

Psychological disorders

Bipolar and related disorders

Bipolar disorder

Feeding and eating disorders

Anorexia nervosa

Bulimia nervosa

Medication-induced movement disorders and other adverse effects of medication

Neuroleptic malignant syndrome

Serotonin syndrome

Somatic symptom and related disorders

Factitious disorder

Somatic symptom disorder

Trauma and stressor-related disorders; Abuse

Physical and sexual abuse

Post-traumatic stress disorder


Attention deficit hyperactivity disorder


0 / 10 complete

USMLE® Step 1 questions

0 / 2 complete

High Yield Notes

6 pages


Attention deficit hyperactivity disorder

of complete


USMLE® Step 1 style questions USMLE

of complete

An 11-year-old boy is brought to the pediatrician by his parents for evaluation of behavior problems. The patient has been frequently interrupting his parents when they are speaking with others. He often forgets to complete tasks assigned to him, such as cleaning up toys or taking out the trash and is easily distracted. His parents state that when they speak to him, he often does not seem to listen. The patient has been performing poorly in school, and his parents are scheduled to meet with the teacher next week. Past medical history is notable for a tonsillectomy at age 9. Height and weight are consistently tracking at the 50th percentile. Physical examination is unremarkable. Which of the following would be most useful in identifying the patient’s underlying condition?  

External References

First Aid








Attention deficit disorder (ADD)

amphetamines for p. 243

Attention-deficit hyperactivity disorder (ADHD) p. 580

drug therapy for p. 596

smoking and p. 638

sympatholytic drugs for p. 244

Tourette syndrome p. 580

treatment p. 726


Content Reviewers

What most people know—or think they know—about attention deficit disorder, or ADD, is that it’s used to describe somebody who can’t stay focused…and when they REALLY can’t focus, they have attention deficit hyperactivity disorder, or ADHD. This continuum from one to the next isn’t quite how it works, though.

ADD and ADHD are actually synonymous, as in, they’re the same.

ADD’s an outdated term used prior to 1987, after which it evolved into ADHD to encompass more of the symptoms that people with ADHD often experience, which in addition to being inattentive, includes both hyperactivity and impulsiveness.

So somebody might be diagnosed with ADHD because they have symptoms related to not being able to pay attention, but they also might be diagnosed with ADHD if they have symptoms relating to being overly active and impulsive.

They might also have ADHD if they have symptoms of both.

According to the diagnostic and statistical manual for mental disorders, the fifth edition, the most recent update being in 2013, ADHD is split into these three subtypes: inattentive, hyperactive-impulsive, or both.

Inattentive and hyperactive-impulse have a set of nine symptoms.

For example, someone with the inattentive subtype might make careless mistakes, or not listen, or be easily distracted; and someone with the hyperactivity and impulsive subtype might fidget, or squirm around, or get up from their chair often.

Now, you might be thinking that everyone fidgets now and then, right? Well a diagnosis is given when someone has 6 of the 9 symptoms for either subtype for at least 6 months.

Most commonly though, children have symptoms of both subtypes and therefore have the combined subtype.

Since ADHD is considered a neurodevelopmental disorder, the symptoms also have to have started between age 6 and 12, and the behavior can’t be appropriate for their age.

Alright, but what causes someone to be hyperactive, or impulsive, or inattentive? Well, as you might guess, it’s pretty complicated...and we don’t really know, probably a lot of different factors, and ultimately they all fall into some combination of environmental and genetic factors.

One interesting clue to a genetic component of ADHD is looking at families—for example, a child with a sibling that’s been diagnosed with ADHD is more likely to develop it themselves.

Furthermore, if those siblings are identical twins, meaning they have the same DNA, their chances of developing ADHD is considerably higher.

Having identical DNA doesn’t mean that the twin is definitely going to develop ADHD, though, which again, suggests that both genetic factors and environmental factors play a part.

As to a specific gene, it’s probably not one single gene that leads to ADHD, but rather multiple genes that determines how severe their symptoms are.


Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.