ADHD: Etiology and Comorbidities

00:01 Hi, I'm Doctor Rhonda Lawes and this is a discussion on the etiology and pathophysiology of ADHD.

00:07 Now a cardinal symptom of attention deficit hyperactivity disorder is this general distractibility. That means that children or adults shift their attentional focus to stimuli that are irrelevant to what they're doing or what they need to be focusing on.

00:22 Now, this has traditionally been attributed to a deficit in the dopaminergic signaling in the corticostriatal networks, and this is what regulates our goal directed behavior.

00:33 Now, I know that's a lot, but it's just a quick review.

00:35 But we're going to break this down a little more.

00:38 Now we talk about executive function.

00:39 That's the set of your cognitive processes.

00:41 And that's what facilitates our ability to have goal directed behaviors and adaptive responses to complex situations.

00:49 This is where people with ADHD can sometimes struggle.

00:53 They have to develop different processes to help them in that area because executive functions are higher order mental abilities, and this is what enables an individual so they can plan, organize, strategize.

01:05 They can prioritize tasks and they can manage their time efficiently.

01:10 Now, as I'm going through this list, I want you to think about your exposure to someone with ADHD.

01:17 These executive functions are where they will struggle, and you start to think about the behaviors that you see.

01:23 So if they have a hard time with planning, organizing and strategizing, it would make sense that prioritizing tasks would also be a challenge.

01:31 They have a hard time knowing what they should do first.

01:35 Now, managing their time efficiently is a problem because sometimes people with ADHD have what we call time blindness.

01:42 They're not aware of how much how much time it would take them to complete a task.

01:46 In addition, they have troubles with regulating emotions and monitoring their own performance. Now, I know that sounds like a really intense list, but people can overcome this. They're not stuck with these behaviors through treatment plans, therapy, medications, and just working on processes in their life.

02:06 They can overcome all these things and become stronger in it.

02:11 The reason is, as a provider, you want to help them improve their executive functions because they're crucial to their problem solving, decision making, impulse control and working memory, which is essential for learning.

02:24 So you want to help them strengthen their executive functioning.

02:29 We're going to talk about an overall treatment plan.

02:31 But before we get into that, in this series of discussions, I want you to understand the etiology and the pathophysiology because this involves the coordination of various cognitive processes, and that is what helps everyone achieve their specific goals and function in their daily activities that require flexibility, adaptability and self-regulation. So let's start with the etiology and pathogenesis.

02:56 Now you'll see on the screen there we have genetics and environmental factors.

03:01 So when you're thinking about what do I need to know as a provider about helping patients with ADHD, I want you to think about the etiology of this.

03:10 So the two categories that you see there are genetics and environmental factors.

03:16 Now what I'm doing with you is I want you to think of me as your study partner.

03:21 I'm studying with you as we go through this discussion because I want these pieces to stick. So you'll hear me use repetition.

03:29 You'll hear me point out things on your slides, because I want you to get the most out of spending this time studying with us and about ADHD.

03:38 So, you know, the etiology, the two factors, there are genetics and environmental factors.

03:42 Those are the ones that are a little more controversial.

03:45 But when it comes to genetics, here's what we know.

03:48 Adhd is strongly influenced by genetics.

03:51 But how exactly genes cause ADHD? It's not really that straightforward, and it involves a lot of factors.

03:58 Now look at that catecholamine metabolism imbalance.

04:02 That's big words for meaning.

04:04 Catecholamines are what help control our attention and behavior.

04:09 If they're not balanced correctly, and the part of the brain that's responsible for the thinking and decision making, i.e.

04:15 the cerebral cortex.

04:16 This imbalance can contribute to symptoms of ADHD that you have likely observed, such as difficulty paying attention, impulsiveness, and hyperactivity.

04:26 So the genetics, we know they're complex, we don't completely understand them, but they're there. And we know that people with ADHD have a catecholamine metabolism imbalance in their cerebral cortex.

04:39 Now let's talk about the cerebral cortex for just a minute.

04:42 I know you know this, but I just want to do a quick review to kind of level set for us together as we're studying together.

04:48 So the cortex is the outer layer of the brain surface.

04:52 That's why I put an image up there of you for the brain and then zero it in so you can see the see the cerebral cortex.

04:58 It's located on the top of the cerebrum.

05:00 And this is what controls memory thinking, learning, reasoning, problem solving, emotions, consciousness and sensory functions.

05:08 And this is where we're going to have some challenges in ADHD.

05:12 Now look at this list of common comorbidities that go along with ADHD.

05:18 Stop. Before you try to memorize a list, I just want you to pull back and kind of see the big picture.

05:23 And that's the best way to remember things, because when you look at this list and you take what we've already talked about with ADHD, you can see how these would have some overlap. Some things that are different and some things that have overlap.

05:37 You've got the list there from autism learning disorders, tic disorders, depressive disorders all the way through that list.

05:45 As we continue with this discussion, you're going to see the areas that overlap.

05:50 But what we wanted to bring this out in the very beginning is because sometimes it's very difficult to distinguish what is ADHD and what is one of these common comorbidities.

05:59 So as a provider, just be aware that these can happen together.

06:04 And you'll have to be very careful in separating out treatment plans and knowing what you're treating. And a lot of it is unfortunately very educated trial and error and observing and talking with your patients and building that relationship.

06:19 So these common comorbidities remember you're back to that.

06:23 Catecholamines. Those catecholamines are what control all those high level cognitive processes. And remember clients with ADHD have an imbalance in their metabolism.

06:35 Now let's look at the environmental factors.

06:37 Okay. So we've already talked about the genetics and we've talked about the catecholamine imbalances.

06:42 Now we're going to talk about environmental factors.

06:44 And this is where people get all worked up right.

06:47 It's still controversial.

06:49 You'll see in the literature people have looked at things, everything from what happens prenatally.

06:54 Natalie. So were they exposed to tobacco smoke or alcohol or drugs? Maybe that has an impact.

07:00 What about patients who had premature birth? They were born early or they had a low birth weight.

07:04 They've looked at lead exposure.

07:06 And, you know, someone can come into contact with lead in old paint or bad plumbing.

07:10 What about a brain injury? Is there a link to that with ADHD? So there is some thought that suffering head injuries can affect brain function and may also contribute to ADHD.

07:20 Severe stress. So someone has a significant stress or trauma early in their childhood and even diet. So lack of proper nutrition or exposure to certain food additives.

07:31 Now, the reason I did not list all of those out for you on the screen is because they are controversial, but know that there is likelihood there is a high likelihood that these can play a factor, but it's controversial to know which ones exactly and to which extent.

07:48 And we didn't want to go down that rabbit hole.

07:50 I just wanted to make you aware of that.