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ADHD Comorbidity, a long analysis.
I wrote a rather lengthy paper on the topic of ADHD Comorbidity, and the regions of the brain that are activated when coupled with low prefrontal cortex activity.
Here's a raw paste of the document
Thanks for reading.
By: Eric Whittle
I am not a professional, I am not a doctor. I am someone with ADHD, and I am fascinated with the diverse range of conditions that come with it, as well as the overactivity of other parts of the brain when paired with ADHD.
ADHD Comorbidity and Cerebral Adaptation
ADHD (Attention Deficit Hyperactivity Disorder) is the inability to focus over extended periods of time, accompanied by restlessness. Most often diagnosed in children, due to a few very conspicuous symptoms, talkativeness, inability to stay seated, and inability to pay attention. This is jokingly referred to as "Teacher Annoyance Syndrome", which isn't really a misnomer when you look at the number of children diagnosed with ADHD. Numbers ranging anywhere from 7% in some areas, and up to 12% in other areas. The average age of diagnosis for ADHD, is 7. However, ADHD affects adults with a frequency not much less than that of children, around 5-7%. They will be the main age group discussed here, but more specifically, adults with ADHD, the comorbid conditions that come with ADHD, and the parts of the brain that are overactivated while having an underactive prefrontal cortex.
Neurology of ADHD
A person with ADHD will show lowered levels of activity in the prefrontal cortex, the two most notably affected organic chemicals in this region are norepinephrine, and dopamine. Dopamine is the brain's reward chemical, it lets you know when you've done something good, because it makes you feel good. Norepinephrine is responsible for focus, motivation, and the fight-or-flight response. Dopamine is converted to norepinephrine, so I'm sure you can see why not having these two chemicals would be detrimental. These two chemicals are synthesized in the prefrontal cortex, but are also synthesized in other areas throughout the body. So a person with ADHD is not devoid of them, but the levels of them are still very, very low. What does a brain without an effective prefrontal cortex do, then? How does it deal with this lack of motivation and reward?
The Different Types of ADHD
There are 7 different types of ADHD, I say "different", here, instead of "distinct", because there are a wide range of similarities between all of them, but there are also key differences. These types have been identified primarily by Dr. Amen, the leading expert in ADHD. They are as follows:
TYPE 1: CLASSIC ADD/ADHD
TYPE 2: INATTENTIVE ADD
TYPE 3: OVER-FOCUSED ADD/ADHD
TYPE 4: TEMPORAL LOBE ADD/ADHD
TYPE 5: LIMBIC ADD/ADHD
TYPE 6: RING OF FIRE ADD/ADHD
TYPE 7: ANXIOUS ADD/ADHD
(A more expansive look at the types, and their respective brain region overactivation, can be found here http://www.amenclinics.com/conditions/adhd-add/)
ADHD and Comorbid Conditions: An Overview
It is well known that there is a high likelihood of other mental health conditions devoloping in combination with ADHD, even when treated, around 50%. It is thought that this is caused by the frustrations and problems that accompany coping with the condition. This is an unsettling conclusion, because 50% isn't small. 50% develop mental conditions, even when given proper treatment from a young age, because they're coping with another condition? In no way do I think that this isn't possible; this is extremely pragmatic reasoning. Everyone copes with things in different ways, and thus the resulting condition would fall in line with whatever coping mechanism they chose. For example, if you cope with your ADHD in a way that causes you to lose hope that anything can change, that might result in depression. If you cope with it in a way that makes you anxious around others because you feel stigmatized due to your condition, you might develop an anxiety disorder. These are reasonable assumptions, and are backed up by clinician's ongoing treatment of their patients, and what the patients tell them.
This is another problem with the treatment of ADHD, and all mental disorders. More often than not, psychiatry is the only field of medicine where the doctor doesn't actually look at the body part they are treating. The patients are not given an MRI, they are given a questionnaire. There are several problems with this method of diagnosis and treatment:
1. People lie
2. People forget
3. The general public does not have substantial knowledge about their condition
4. A set list of questions is a very rudimentary way to diagnose a sometimes lifelong
condition that effects several aspects of life.
ADHD with Comorbid Depression
20-30% of those with ADHD have some sort of learning disability that is attributed to the ADHD itself, and by extension, the inactivity in the PFC. So those affected by other conditions are somehow not a result of the brain functioning due to inactivity in the PFC. That is what most assume. Again, 20-30% is not a small number, but learning disabilities are the only comorbid condition that is attributed to the root problem. All others are assumed to be an auxiliary effect of dealing with the condition, which is sometimes true. However, developing an entirely separate medical condition due to dealing with an existing one and the problems that come with it, isn't as cut and dry as it sounds. When SPECT scans are used, the areas of the brain associated with the comorbid condition are active. This is true for anyone with a mental condition, for this example, depression. There are several areas of the brain that are affected due to depression, Dr. Amen's SPECT scan results summarize it best "Decreased prefrontal cortex activity with increased deep limbic system (thalamus) activity. This subtype is often associated with symptoms of moodiness, negativity, low energy, sleep and appetite problems and poor concentration. It often responds best to dopaminergic or noradrenergic interventions such as buprion, imipramine or desipramine."
The above is an example of just one type of depression. In this type, the PFC has decreased activity, and the limbic system (thalamus) has increased activity. Sound familiar? That's because it's the fifth type of ADHD. Limbic ADHD, which is characterized by "Primary ADD symptoms plus chronic mild sadness, negativity, low energy, low self-esteem, irritability, social isolation, poor appetite, and sleep patterns.". It is ADHD and depression wrapped up into one condition. This is nothing new, Dr. Amen has written books on much of what I've said here, if not all. But the incorrect way of thinking remains. The accepted way of thinking in psychiatry stipulates that a single condition is a single condition, all those that follow are auxiliary, and separate.
Cerebral Adaptation: An Overview
The brain is comprised of receptors, and communicates with itself, and the rest of the body, through electricity. Neurotransmitters. It's like an elaborate machine, and, like any machine, it takes more than a few parts to make an executive function. A brain without the ability to harness the prefrontal cortex has other means of preserving the body, and getting through life. It uses other parts of the brain which act like norepinephrine and dopamine, to much effectiveness in some cases, and pure detriment in others.
Much like the old tale of putting moonshine in a gas tank when you don't have gasoline, the ethanol in the moonshine acts like gasoline. It's octane rating is within range. It combusts. It doesn't stop any of the parts from working, it gets you where you need to go. However, constant usage over time results in degradation of the engine. This is analogous to the way the brain utilizes other centers to mirror the effect of the prefrontal cortex. Whether by coincidence or purposeful reinforcement.
The effects of the different types of ADHD can be learned about through Dr. Amen's website. The reason there is a differentiation between the types is due to the parts of the brain that are selected when the PFC (Prefrontal Cortex) is inactive, or otherwise ineffective. These different parts are identified by Dr. Amen, but the reason for them being selected and the intricacies of the parts selected are not delved into in any way. Why are they selected? Why do they work effectively as a substitute for the PFC? Are they a substitute at all? Could it be that the parts of the brain that are selected and become overactive are just coincidence?
Selective Cerebral Adaptation
The natural selection of beneficial traits is widely known, and accepted. Here, I won't use Darwinian examples dealing with entire generations selecting traits. I will instead use another well known example. Blindness. A blind individual's senses, other than sight, are heightened when given enough time, even without purposeful training of those senses. Not just the five main senses we are taught about as children, there are up to twenty one different functions that could be categorized as "senses". From balance, to heat detection. Many of them function at a much higher level than those with sight.
This is also true for some that are affected by autism. The affected individual cannot tie his or her shoes, but can recite entire symphonies from memory on a piano, after only hearing the piece once. There is also substantial research into the reason for this. Those reasons being, that when the brain cannot be used to perform behaviors that are considered necessary to survive, or be accepted socially, it instead uses those centers to do much more extraordinary things. This would have gotten you killed if humans still lived as hunters and gatherers, but is very useful and fascinating in a world where we do not have to worry about those above us on the food chain. Instead of having to manually exercise these regions in order to achieve these seemingly unachievable feats, it automatically activates the centers responsible, and keeps them activated. Eliminating the need for repetition and learning. The autistic brain, in some instances, bypasses the need to learn, using working memory to great efficiency, resulting in profound applied results. They are not doing anything that a person with an unaffected brain couldn't do, they are just doing things so quickly it seems that way. Does anyone applaud a man who goes to college for years, gets a Ph.D, knows his entire field in an out, and does his job? After the graduation ceremony, not usually. But when those years of dedication and learning are applied all at once in a short amount of time, you could imagine the envy that man with a Ph.D would feel for someone affected by autism. What you could not imagine, is how the person with autism feels. Constant sensory input, inability to speak, ceaselessly overwhelmed. A fully charged battery with nothing to expend it's energy on. If those with this extreme and rare form of autism could speak, that man with a Ph.D would not be so jealous.
Brain Regions: Overactivation in ADHD Types
The 7th type of ADHD, activates the basal ganglia, causes anxiety, worry, doubt, and constant negative thought. These are traits which the basal ganglia is used for. This region has a dual purpose, though (as do all of the regions that are overactivated with their respective ADHD subtypes). It is also responsible for the control of voluntary motor movements, procedural learning, routine behaviors or "habits", eye movements, and cognition. Accompanying those negative outcomes of overactivity are a few very positive ones that may occur, due to the nature of the basal ganglia (as well as a few that are just peculiar)
1. Voluntary motor movements- Improved dexterity, when combined
with the other positive effects, proves very useful. The opposite end is apparent, too.
Resulting in involuntary movements. (see number 3)
2. Procedural learning- Can follow direction (when interested) with autonomous
efficiency. Can also create directions, quickly, and efficiently.
3. Routine behavior, "habits"- Constant, repetitive movement of the extremities. Tics.
Combined with number 1 and 2, propagates the ability to do repetitive procedural
tasks that require good hand eye coordination, with minimal effort.
4. Cognition- Improved problem solving, memory, working memory, "computation",
decision making. Again, the opposite end is apparent. Lack of attention, judgement, and
The 3rd type of ADHD, which has a primarily overactivated anterior cingulate cortex (ACC), results in cognitive inflexibility, trouble shifting attention, being stuck on negative thoughts or behaviors, worrying, holding grudges, argumentativeness, oppositional, and saddled with a need for routines. The ACC is also responsible for rational cognitive functions, reward anticipation, decision-making, empathy, impulse control, and emotion. Again, the same case as ADHD type 7, those functions which do not impact the person negatively, impact the person positively. Someone with ADHD type 3 may have the following occur, due to the nature of the ACC.
1. Rational cognitive functions- When this is improved in the person with ADHD
it results in both positive and negative outcomes. Rationality is a good trait to have,
but not if it is coupled with a lack of empathy, impulse control, and emotional self
awareness. The person would seem calloused. Almost too rational, but cannot
maintain control over their own emotions.
2. Reward anticipation- Improvement of this mechanism in someone with ADHD
would mitigate some of the effects of an ineffective PFC, as well as make others worse.
The person would have drive to do something to completion, regardless of focus,
the person would come back to the task after losing interest, in anticipation of reward.
However, since dopamine is not present, there is no actual chemical reward.
Resulting in frustration, thinking they have failed. Or, thinking that they "can't do anything
3. Decision-making- Another counteraction to the symptoms of ADHD. Improved
ability to make decisions lessens the severity of impulsivity. In combination with
improved reward anticipation, makes the person with ADHD less prone to doing
things that are reckless or harmful
4. Empathy- Primarily negatively impacted due to the lack of dopamine. Can
be positively impacted depending on experiences with other people.
Holding grudges would only be natural if impacted negatively.
5. Impulse control- Yet another counteraction to the symptoms of ADHD. Better
impulse control, but not total impulse control. The person is more aware when they
give in to the impulse, resulting in frustration.
6. Emotion- Negatively impacted, furthering the assumption that the person is calloused.
Inability to empathize, combined with the inability to reconcile their own emotion
leads to oppositional defiance, and argumentativeness.
These are just two glaring examples of what the brain does without proper function of the PFC, within the types of ADHD. This same balancing act can be done with every single type.
Purposeful, Accidental, or Selective; Nature or Nurture
Now, is the overactivity in specific regions in the brain the result of the brain knowing it needs PFC stimulation, so it substitutes another part of the brain while searching for that stimulation? Or are they activated due to genetic predisposition? Do those centers get used more due to experience in childhood and adolescence? Or, the most reasonable assumption; all of the above.
Whether the regions of the brain are overactivated to adapt to the PFC deficiency, or as a result of coincidence is an issue here. As it stands, there is no real way to know. There hasn't been enough research done on this topic. The most that can be done from my end, is to learn about the intricacies of the brain, and hope I can one day learn by directly observing, instead of just studying.
Title: Neurology of ADHD
Title: ADHD and Comorbid Conditions: An Overview
https://www.mentalhelp.net/articles/adhd-comorbidity/ ; http://www.medscape.org/viewarticle/418740
Title: ADHD With Comorbid Depression
Title: Selective Cerebral Adaptation
Title: Brain Regions; Overactivation In ADHD Types
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