2-Minute Neuroscience: ADHD

​Attention-deficit/hyperactivity disorder, or ADHD, is a condition characterized by difficulties with attention and/or hyperactivity and impulsivity. In this video, I discuss perspectives on the neuroscience of ADHD.​

TRANSCRIPT:

Attention-deficit/hyperactivity disorder, or ADHD, is a condition characterized by difficulties with attention and/or hyperactivity and impulsivity. ADHD involves strong genetic influences, but environmental factors, and interactions between genetics and the environment, are thought to play an important role in ADHD as well.

Much of the recent research into the neuroscience of ADHD has focused on understanding the brain networks that might underlie different aspects of cognitive function in ADHD. One example is the default mode network, which is a collection of brain regions that is more active during mind-wandering and introspection, and less active when a person is attempting to complete a specific task. Studies have found that people with ADHD have atypical connectivity in the default mode network, which might be associated with distractibility.

Individuals with ADHD also display lower activity in brain networks that are involved in attention and cognitive control. Typically, activity in these networks increases when activity in the default mode network decreases, and vice versa. Thus, one hypothesis is that in ADHD activity in the default mode network is dysregulated and interferes with the function of networks involved in attention and cognitive control.

Studies have also found that people with ADHD tend to display atypical activity in the reward system, a group of structures that are involved in motivated behavior, anticipation, and reinforced learning. This atypical reward system activity might be associated with a tendency to overestimate the value of short-term rewards in comparison to long-term rewards, which could also affect planning and decision-making. The reward system includes some of the major dopamine pathways in the brain, and dopamine is often implicated in ADHD because medications that are commonly used to treat the condition, such as amphetamine and methylphenidate, cause increased transmission of dopamine and norepinephrine.

REFERENCES:

Faraone SV, Asherson P, Banaschewski T, Biederman J, Buitelaar JK, Ramos-Quiroga JA, Rohde LA, Sonuga-Barke EJ, Tannock R, Franke B. Attention-deficit/hyperactivity disorder. Nat Rev Dis Primers. 2015 Aug 6;1:15020. doi: 10.1038/nrdp.2015.20. PMID: 27189265.

Gallo EF, Posner J. Moving towards causality in attention-deficit hyperactivity disorder: overview of neural and genetic mechanisms. Lancet Psychiatry. 2016 Jun;3(6):555-67. doi: 10.1016/S2215-0366(16)00096-1. Epub 2016 May 13. PMID: 27183902; PMCID: PMC4893880.

Posner J, Polanczyk GV, Sonuga-Barke E. Attention-deficit hyperactivity disorder. Lancet. 2020 Feb 8;395(10222):450-462. doi: 10.1016/S0140-6736(19)33004-1. Epub 2020 Jan 23. PMID: 31982036; PMCID: PMC7880081.

[omarbadran]

ADHD is a misnomer that most scientists in the field want to change to something like executive function disorder. And the reason they are not changing it is mostly politics inside the DSM committee. It's way more complex than blaming a neurotransmitter or a network. I have treatment resistant ADHD and been researching and trying medications since I was 14, and now I'm 22 and barely started to see improvements after trying every f'ing psychoactive drug available in my country. I'm a software engineer and I have nothing to do with biology, but here is a small explanation from what I understand about the disorder:

As for the dopamine hypothesis, research does show that ADHD has a lot of dopaminergic abnormalities, but that does not explain a lot. It also contradicts with a lot of other facts that we know about ADHD. For example, some ADHD drugs (e.g. Intuniv) and most of the ones that are being developed right now barely touch dopamine at all. And most of Parkinson's drugs that increase dopamine either don't show any benefit or a very small one and only rarely used to augment stimulants (i.e. amantadine). So how would the dopamine hypothesis explain that? And how do we explain the fact that drugs such as stimulants which are insanely powerful at increasing dopamine only helps about 80% of patients and out of these about 40% of them don't get full symptomatic relief. And how does the DMN abnormality explain a lot of the symptoms such as emotional dysregulation, time-management problems, delayed circadian rhythm phase (Up to 75% of adult patients), and motor coordination problems which are present in most ADHD patients?

It's a very long subject, but the most recent explanations of ADHD is that it's an executive function disorder that affects all the functions related to goal-directed behavior. You can think of attention as the navigation system of your brain, that is always scanning the environment and once a stimulus is relevant to a goal, your brain releases dopamine which then increases the silence of that stimulus, which shifts your attention to it and allow you to sustain your attention and helps you problem-solve that task using your other executive functions (i.e. manipulating the environment according to your goals). And along this process, there are multiple parts of your brain that each has a role in this system. For example, if you get distracted by something that has an emotional component to it (i.e. anger at a coworker) usually the DLPFC is the part that allows you to inhibit that automatic response if inhibition was the preferred long-term response according to your goals (i.e. not getting fired). Now if the distraction is something such as an idea to go do something more rewarding (watch YouTube videos), then other parts of the PFC engage in a coordinated way to inhibit that behavior and go back to the task at hand. And the list goes on for other processes related to executive functioning such as planning, prioritizing and sustaining, and shifting attention, regulating alertness, and processing speed.

So when we treat ADHD, we do our best to shift this abnormal connectivity closer to normal as much of that as possible. And this abnormal connectivity is slightly different for each patient, as ADHD is a "highly complex and heterogeneous disorder".

Now obviously stimulants play a huge role which is why they are the first line medications, but most of the time patients need a combo of drugs such Intuniv+Stimulant, Strattera+Stimulant, Qelbree+Stimulant, etc. So that we cover as many affected areas as possible. And we have new drugs being developed that target totally different systems, such as H3 antagonists like Betahistine, and Nicotinic agonists like ABT-089.

CBT also plays a huge role, although not very effective without medications. But studies show that the combination of CBT and stimulant treatment is more efficacious than either alone. And not any form of CBT, only the one designed specifically for ADHD, such as the ones developed by Russell Ramsay or Mary Solanto.

Here is a good start:


(This wall of text is proudly brought to you by Ritalin)
(Also, fuck, I should be working right now)

[amtahboub]

This is extremely validating.. ten years on I still feel like a fraud when I go to my psychiatrist for ADHD

[dontbeabutt]

I had to watch this like 4 times because I kept looking at the sidebar but after the 4th time I was very validated thank u

[powerpuff_avenger]

I got tested for ADHD once (in 1 day) and they said I didn't have it, despite constantly fighting mentally to compete the tasks given to me. Most of the time, it takes A LOT of energy to focus and I find myself just "gone", staring blankly at my screen when reading something or following an online class. The movements of the teacher in an on site class keep me focused a little bit better (especially when there are no windows I can easily stare into without going owlish with my neck). I can be pretty impulsive (I will think I've thought about a decision long enough, no one else really agrees lol). I'm getting re-evaluated for autism/ADHD atm, we'll see how that goes...

[darthrincus]

ADHD is scrolling through the coments while the video is playing

[zach]

That was a wonderful watch, it feels extremely validating to see someone so elegantly explain what I couldn't put into words for a long time.

[aamirrazak]

Great video I feel i learn something new every time I watch one of your videos! If ADHD involves deficits with dopamine, I wonder if treatments for Parkinson’s which involves destruction of dopaminergic neurons, could help alleviate symptoms of adhd

[scottw]

I had ADHD in 1961 at St Pacal's Catholic School in Toronto, Ontario and my Nun teacher tried to beat it out of me with the strap, Scott, "Are you ready for your daily strapping?" but this dosen't even compare with the abuse dished out at the Residential Schools in CANADA on the indigenous young people at the time.

[muhammedcagrkartal]

man the content is great
please start doing cognitive neuroscience videos as well.

[eleksitia]

I just finished watching the video on Autism Spectrum Disorder, your video on Restless Leg Syndrome, and now this video on ADHD (in that order)


I have all three of these,


I also enjoyed the videos. The short form format helped me keep my attention on them.

[elywood]

If you believe you may have ADHD inattentive type or are treatment resistant, look into sluggish cognitive tempo.

[zhill]

As someone with severe adhd that is in college to be in both pharmacology and neuroscience, After alot of thinking and personal feelings and experiences, i think its both genetic and how you grow up/how its managed throughout puberty.Now my hypothesis is people like me probably have a genetic mutation on Dopamine receptor D2, aswell as D1 and D4.I also believe People with adhd tend to have excess amounts of norepinephrine, dopamine within their synaptic cleft.People with severe adhd may also have tics, coming from rapid dopaminergic influxes.ALSO people with adhd have a higher chance for risk taking and addiction because Of Dopamine fluctuations, this is also due to a mutation in Monoamine Oxidase, allowing more monoamines to be in the blood.Lastly, my recent studies have shown that The striatum & Dorsolateral Prefrontal cortex in people with adhd functions both more effectively and neuroplasticity happens in a quicker manner.I believe the DLPFC is a bigggg target for this.

[levelthefield]

Your videos are amazing! Thank you for introducing me to the field of neuroscience in an unintimidating and fun way!

[senseofmindshow]

Awesome summary! Whenever I hear about the neurological causes of psychiatric conditions, my mind always goes to individual variability. It sometimes seems like neuroscience is trying to find single causes of conditions that may, in reality, be clusters of symptoms that each have different (though sometimes overlapping) causes. My guess is that neuroscience combined with genomics and behavioral genetics will start to show that. Thank you for your content!!

By the way, I make neuroscience videos as well and I’m wondering if you’d ever be interested in doing an interview on my channel?

[AngDevigne]

OMG!!! So happy you posted this. Thank you.

[Brandon-tzpn]

Got to the end of the video and realized I was lost in thought and didn't listen to a thing. I literally cant finish this video. This is the 4th time I had to replay it.

[jacksonmajor]

My foundations of behavioral neuroscience teacher plays your videos in class

[quietnerdything]

Funnily enough, I had to rewatch this twice to actually pay attention to everything

[kerstoneshepherds]

I got to about 0:22 when i suddenly did the *back to reality head shake* as i said "wait, what??" realizing i had ALREADY zoned out. Oops. LMFAO Going back to finish watching now, then the COVID 19 video next. Post-COVID brain was like taking my usual ADHD and cranking it up from a level 10 to level 100. And the aphasia was horrible, very frustrating, and rather scary.... to know that you KNOW something, but its like totally random bits of data being corrupted or deleted from your harddrive.

[ellibrador]

Anybody else set the speed playback to 0.5 to keep with this guy and understand the video?