What is ADHD?
–persistent pattern of inattention and/or hyperactivity-impulsivity.
–Hyperactivity refers to excessive motor activity at inappropriate times (this could include running around, fidgeting, tapping, or talkativeness)
–Impulsivity refers to hasty actions that occur in the moment without any kind of forethought.
Clinically relevant forms of impulsivity typically involve possibly harmful behavior (i.e. running into traffic).
How is ADHD diagnosed?
- -classified as a developmental disorder by the DSM5
- -ADHD begins in childhood, and the DSM5 requires that symptoms be present before age 12
- -these factors must be shown to impact development in a clinically significant manner meaning the adhd has to affect the individual and others to be diagnosed
What is the difference between ADHD and ADD?
According to the latest version of the DSM (DSM-5), ADD is not a diagnosis
You are either predominantly inattentive, predominantly hyperactive, or a combination of both
What are the key features of ADHD?
Children inevitably have occasional bouts of inattentiveness or hyperactivity – those are part of growing up. A key feature of the ADHD diagnostic is that manifestations of the disorder must appear in multiple settings.
This means that ADHD symptoms are not just limited to one place (school, for example), but appear no matter where the child is.
What makes ADHD hard to diagnose?
Context matters. Signs of the disorder may be minimal or absent when the individual is under close supervision, receiving frequent rewards for good behavior, in a novel setting, or doing something interesting.
This can make the disorder challenging to diagnose, as the doctor’s office often meets all of the above criteria.
How can ADHD cause other problems?
Academic performance tends to suffer
Social rejection is common as well (can result in depression)
Other comorbid disorders may also make it more challenging (e.g., ASD, OCD)
Why is ADHD not considered an intellectual disorder?
ADHD is not considered an intellectual disorder per se. Nevertheless, mild delays in language, motor and social development are common in children with ADHD.
This could be a consequence of simply not paying sufficient attention to things
What is the prevalence of ADHD?
–approximately 7.2%
–Male to female ratio is about 3:1
–Adult ADHD may have a prevalence as high as 2.5%. symptoms gradually reduce across the lifespan, but persist in 30-50% of cases.
impulsivity and hyperactivity tend to drop off more than attention. Many adults continue to struggle with attention their entire lives.
What is ADHD prevalence worldwide?
- -ADHD prevalence appears to vary worldwide, though not by as much as is often claimed.
- -North America, when considered as a whole, has higher rates of ADHD than most other places (South America and Africa being exceptions).
How has the DSM diagnostic criteria for ADHD changed over time?
- ADD was first defined in the DSM-III with three domains: Inattention, Impulsivity, and Hyperactivity. Children required several symptoms in each domain to receive a diagnosis.
- -The DSM-IV continued with this model, but allowed for diagnosis of either symptoms of inattention or hyperactivity symptoms. These seem to be less strict diagnostic criteria.
- -The DSM5 retains similar criteria to the DSM-IV, but removed ADD
Why is it hard to tell whether ADHD rates are increasing?
Since the diagnostic criteria has changed over time (from DSM-III to DSM-IV to DSM-V), it can be difficult to tell whether ADHD rates are actually increasing, or if it’s simply a matter of diagnostic criteria changing
How do cultural factors affect the diagnoses of ADHD?
- -Hyperactivity and inattentiveness would not be as much of a concern in times and places where children do not go to school (ex. hunter-gatherer children)
- -On the other hand, in areas where academic achievement is prized above all else, even minor levels of inattentiveness and hyperactivity would seem pathological
- -The current DSM5 diagnostic criteria still seems to be based largely on elementary school-aged North American boys
- -disorders such as anorexia nervosa are also highly dependent on cultural context
What is the comorbidity of ADHD?
Only about 1/3 of children are diagnosed with ADHD alone. The majority are diagnosed with at least one other DSM disorder
What is oppositional defiance disorder?
showing defiance in the face of authority
What is the genetical cause of ADHD?
–research has not yet uncovered much in the way of specific genes that might be to blame
—->Weak associations have been found with genes for the dopamine reuptake transporter and the D4 dopamine receptor
—->Theres two types of receptors for dopamine,
D1 and D2. D1 includes D1 and D5
D2 includes D2, D3, D4
—->The functioning of the reuptake transporter is altered in ADHD and the D4 receptor
What is the etiology of ADHD?
–The etiology of ADHD has been suggested to be up to 80% genetic. This makes it one of the most heritable disorders
Who is at an elevated risk of ADHD?
–ADHD is elevated in first-degree biological relatives of individuals with ADHD
What can smoking affect ADHD?
Children with a specific mutation in the dopamine reuptake transporter (DAT1) are more likely to exhibit symptoms of ADHD if their mothers smoked during pregnancy.
- –cigarettes contain nicotine which stimulates the central nervous system and specifically elevates activity in the prefrontal cortex. People who smoke nicotine products may be self-medicating mild ADHD
- –this alters the expression of those post-synaptic receptors which then crosses the placenta and impacts the brain development of the baby
What is perinatal hypoxia?
- -a temporary shortage of oxygen around the time of birth has also been linked to the development of ADHD
- -not getting enough oxygen may cause some cells to die (the hippocampus and the prefrontal cortex are some of the most vulnerable parts of the brain so if there is some trauma these are the brain regions that tend to be impacted and we see a range of symptoms as a result)
- -Perinatal hypoxia can result in a range of developmental disorders
What is the stanford marshmallow experiment?
- -late 1960s, psychologist Walter Mischel
- -children (ages 4-6) were brought into the lab and offered a treat of some kind, usually a marshmallow
- -They were told that they could eat the marshmallow right away, or they could wait 15 minutes and get two marshmallows instead (the researchers said they would be back at some unspecified time)
- -The experimenter would then leave the room, and observe the child through a two-way mirror.
- -Delayed gratification is one of the functions of the frontal lobe (as it grows, it allows people to have better delay of gratification and less likely to behave impulsively)
- -Addiction is a disorder marked by failure to delay gratification
- -The children that were able to wait had better executive functioning, more successful and more likely to pursue higher education
What are the behavioural markers of ADHD?
- -Children with ADHD will usually opt for immediate reward in psychological studies (such as the marshmallow study).
- —>This seems to happen regardless of previous experience in the experiment
- -Rewards apparently have less of an influence over the behavior of children with ADHD.
- —>Children’s performance in various cognitive tasks (tests of reaction time, accuracy, etc.,) improves when a reward is offered (rather than a punishment). This is not the case in children with ADHD – their performance remains low irrespective of reward.
What is the go/no-go task?
- -Children with ADHD have impaired performance in go/no-go tasks
- -Go/no-go task: kids sit in front of a screen and they get told to press enter when they see certain letters (go signal). Everything else is no-go. You have to inhibit the response to press the enter key. Kids with ADHD make many errors in omission and commission. They’re not paying attention enough to hit the key properly when they see those letters and they hit the key inappropriately (error in commission)
- -Interestingly, relatives of children with ADHD also show impaired performance on these tasks, even if they don’t have the disorder themselves. This suggests a possible endophenotype.
What is an endophenotype?
clustering of genes that code for specific functions that first-degree relatives may have some of that expression but may not show that exact constellation of disorder (ex eye tracking behavior in first-degree relatives of schizophrenia). We have genes that code for proteins. Certain genes are located right next to each other which could code for similar proteins. As a first-degree relative you may inherit specific protein or polymorphism (combination of DNA sequence) in your genes that makes that protein expression different (higher uptake or breakdown of dopamine in the prefrontal cortex)
What is the Iowa gambling task?
- -measures risk taking and impulsivity and assess the functioning of frontal lobe
- -Patients are given 4 decks of card and they’re told to pick from the cards randomly. The object of the game is to win as much money as possible and to lose as little as possible. Unbeknownst to them, two of the decks are high risk decks (meaning the pay-offs are big but so are the losses). The other two decks are low pay-off but also low loss.
- -Patients who have frontal lobe disorders, addiction, ADHD, they tend to pick from those high risk cards repeatedly (show more risky behavior)
