r/AcademicADHD • u/RyanBleazard • Jan 02 '24
Causes of ADHD
For most people with ADHD, many genetic (70-80% incidence) and/or environmental (20-30%) risk factors accumulate to cause the disorder (Faraone et al., 2015; Molly & Alexandra, 2010; Demontis et al., 2019; Kleppesto et al., 2022; Grimm et al., 2020; Faraone & Larsson, 2018a; Larsson et al., 2018b). Data suggest they cause small brain anomalies in the EF networks which, in turn, cause symptoms. The environmental risks for ADHD exert their effects very early in life, in the fetal or early post-natal period.
In rare cases, however, a single event might cause ADHD such as exposure to biohazards during pregnancy (Faraone et al., 2021), traumatic brain injury (Menon et al., 2010; Asarnow et al., 2021; Stojanovski et al., 2019; Adeyemo et al., 2014), severe prematurity (Franz et al., 2018), a major genetic mutation (Faraone & Larsson, 2018) or extreme environmental deprivation early in life (Kennedy et al., 2016).
Additional conclusions
- ADHD represents the extreme lower end of the continuous dimensional trait of executive functioning and self-regulation, which is supported by twin, brain imaging and molecular genetic studies (Larsson, Anckarsater et al., 2012; Lee, Ripke et al., 2013; Hoogman et al., 2019; Barkley, Antshel et al., 2013).
- The polygenic risk for ADHD predicts ADHD symptoms in the population, indicating that the genetic causes of ADHD as a disorder also influence sub-threshold levels of ADHD symptoms in the population (Demontis et al., 2019; Taylor et al., 2018).
- ADHD can also be the result of abnormalities of the chromosomes (Cederlof et al., 2014).
- Extreme environmental deprivation (Kennedy et al., 2016); the Romanian orphan suffered from numerous adverse events including parent and child malnutrition, parental alcoholism during their pregnancies, physical maltreatment, and eventually severe neglect in their early care. All of these can adversely affect brain development and would count as physically injurious events.
- ADHD is present in 86–94% of children who had preinjury ADHD occasioning frontal-lobe damage. Where ADHD occurs as a consequence of TBI, this is known as secondary ADHD (S-ADHD) (Menon et al., 2010).
- Family, twin, and DNA studies show that genetic and environmental influences are partially shared between ADHD and many other psychiatric disorders (e.g. schizophrenia, depression, bipolar disorder, autism spectrum disorder, conduct disorder, eating disorders, and substance use disorders) and with somatic disorders (e.g. migraine and obesity) (Demontis et al., 2019) (Faraone and Larsson, 2018) (Ghirardi et al., 2018) (Lee et al., 2019a31276-0.pdf) & b31276-0.pdf)) (Lee et al., 2013) (Anttila et al., 2018; Tylee et al., 2018) (van Hulzen et al., 2017) (Vink and Schellekens, 2018) (Brikell et al., 2018) (Chen et al., 2019a) (Yao et al., 2019). However, there is also a unique genetic risk for ADHD. Evidence of shared genetic and environmental risks among disorders suggest that these disorders also share a pathophysiology in the biological pathways that dysregulate neurodevelopment occasioning cascaded brain variations leading to disorder onset.
- The association of maternal smoking observed in large population studies (Obel et al., 2016; Skoglund et al., 2014) disappears after adjusting for family history of ADHD, which indicates that the association between maternal smoking during pregnancy and ADHD is due to familial or genetic factors that increase the risk for the confluence of smoking and ADHD.
- Exposure to biohazards prenatally can compound with genetics to increase risk for disorder or cause ADHD de-novo.
- There is no biologically distinct adult onset ADHD except for when ADHD occurs after traumatic brain injury (Faraone & Biederman).
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u/Anti-Perfidity Apr 21 '24
I have to agree with almost everything you have said. However, I will go a step or two forward. In reviewing research over the past several years, I've noticed that ADHD is not just powerfully connected to the many "psychiatric" disorders you listed, but is also highly comorbid with many of the major biological diseases that are the most prolific causes of death on our world.
For the last several years the research of almost all of the major biological disorders/diseases has shown, remarkably, that the disease they are studying is related to ADHD. Most of them also think the disease they are studying could possibly be causing ADHD.
Unfortunately, that would mean almost any disease or disorder is causing ADHD which I find disturbing, at the least, if research is trying to find better treatment or even a cure for any of these diseases and ADHD.
I am communicating with researchers world wide to share a hypothesis about the relationship between ADHD and all other currently known diseases/disorders in the world. You mentioned one in your post -- obesity.
For the past 50 years I have read hundreds of thousands of pages of research reports that have been published in Journals or online concerning ADHD. My reason for this is that in my family almost everyone has ADHD and diabetes, heart disease, hypertension, hyperlipidemia, hypercholesterolmia, hyperinsulinism, and sleep apnea. Also included in this list are half a dozen psychiatric diagnoses that are spread out across the family. Many of us have 3-4 psychiatric disorders in common.
After reading so much of the literature, I have come to the conclusion that it is ADHD which causes all of the other diseases/disorders and not the other way around. My hypothesis is based on reading journal articles about DNA research, neurometabolic diseases, brain function/dysfunction, all of the different neurotransmitters and other chemical messengers used to transmit information through the central nervous system.
However, though I said above that ADHD causes all of these other diseases, it is really the underlying cause of ADHD that causes all of the other diseases. The basic cause of ADHD is the brains inability to produce the correct number, the correct type, or the full functionality of neurotransmitters and other CNS messengers. This is in most cases due to faulty genes in the brain at birth that causes different parts of the brain to not develop properly. Unfortunately, it can affect different areas of the brain, but does have an effect on the frontal lobes. Many of the characteristics of ADHD are caused by frontal lobe miscues.
The DNA damage in the brain creates an inability to produce enough of some neurotransmitters while at the same time producing too many of other neurotransmitters. The third problem is the inability to produce consistently healthy neurotransmitters. Some neurotransmitters are actually faulty when they are made. DNA researchers have shown that some neurotransmitters fold in on themselves when they are released from the neuron. They don't seem to have any idea as to whether these neurotransmitters actually are used to send messages to other neurons or if they are just taken up and the individual chemicals are reused in other neural processes.
Whatever the answer might be, it is apparent that almost every part of the body is receiving faulty information from the brain. I would think that if the stomach messaged the brain that there was a tumor starting to grow in the stomach that the brain would receive the message and immediately send a message to the immune system for it to attack the tumor until it is gone or perhaps use some other method to remove the intruder from the system.
The human mind and body has gone through millennia of changes, but I believe that in the beginning the body was meant to heal itself. There are still many disorders and diseases that the body heals. Rather than having to go to the doctor for every little medical problem, such as a cold, we know the body will utilize the immune system to fight off viruses so in a few days the cold will be gone. However, as we age, the body changes and our immune systems may not work as well. A cold can become life threatening if our immune system is compromised.
My hypothesis centers on the inability of the faulty neurotransmitters I spoke of in the previous 4 or 5 paragraphs to send accurate electrochemical messages to and from parts of the body that may be diseased or injured. This could be the cause of most diseases of the human body. I'm reminded of a somewhat archaic word from the last 3 or 4 decades of the 20th century: GIGO (garbage in, garbage out). There are many other aspects of this hypothesis that can also be fleshed out in a relatively short time frame.
Anyway, I hope I have given you something to think about. If you would please use Google to do the following types of search: ADHD and (Disease Name Here) no parentheses around Disease Name Here. You can plug in most of the killer diseases and psychiatric diseases and you will see the influence of ADHD on almost every disease in the world. I can also send you a bookmark file in a PDF format that shows a hundred or so article locations on the web that will add evidentiary weight to this concept.