Autism disorder has a wide spectrum of severity ranging from high functioning to low functioning individuals. This disorder is characterized as affecting communication skills, social behavior and learning abilities. Autism has been distinguished as highly genetic but new evidence has linked environmental factors during gestation of a human baby and the susceptibility to it has to being born with autism.
There are many environmental factors that I have been linked to autism including zinc deficiency in the mother, maternal diabetes, the age of parents during conception as well as prenatal exposure to various toxins including valproic acid or thalidomide. The factor that I want to focus on in this blog post is stress on the mother and its affect on the baby being born with a form of autism. No mother wants to hear that it is their fault their baby developed a form of autism, but recent research has shown that heightened prenatal and perinatal stress has been seen to possibly lead to increased chances of their baby developing a form of this disorder.
The hypothalamic pituitary adrenocortical (HPA) axis plays a major role in the regulation and response to stress. When the HPA axis is activated, there is a release of cortisol, which is the primary stress hormone in humans. Cortisol stimulates placental adrenocorticotropic-releasing hormone (CRH) in pregnant women and fetuses so there is a positive feedback loop created between them. Cortisol is needed in normal fetus development but too much of it has been shown to have very negative affects. Under stressful conditions and sustained activation of the HPA axis in the mother, there is a loss of the positive feedback loop between the mother and child due to extremely high levels of cortisol. With the imbalance of cortisol (levels being too high) and the loss of the positive feedback loop, research has shown that there is an increased risk in the occurrence of Autism in the developing baby. Pregnant women general have 2 times higher cortisol levels than that of non-pregnant women, so as I said cortisol is needed in normal fetus development. It is when the levels of cortisol are TOO high (due to sustained activation of the HPA axis) that the baby could be affected.
There are more cases of Autism disorder than ever before and many do not know if this is due to an actual increase in the incidence of Autism or if it is simply being over-diagnosed. Regardless of that issue, there seems to be many different factors that can cause Autism to arise in a person. Genetic factors as well as environmental factors have been scientifically shown to play a role in the risk of Autism arising in an individual. It wasn’t until reading this article did I realize how many things could do wrong in a pregnancy and yet somehow millions of people all over the world are able to give birth to healthy babies everyday. It amazes me that healthy babies can even be born due to the large amount of factors that could affect a fetus negatively. Hopefully more research will give rise to more information on this disorder which overall is quite the mystery because there is still no cure.
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The Environmental Autism
Autism is a disorder that most of us have heard of and are aware of some of the behavioral issues that can accompany someone diagnosed with this disorder. Autism is a developmental disorder that can range on a wide spectrum from Asperger’s disease to severe autism. It’s characteristics include awkward social behavior and trouble communicating with others.
Scientist have been conducting research about this disorder but are still unsure what exactly causes it. They have learned that like most brain disorders genetic factors can play a role in it. Also they have found that nutrition and other factors such as stress during fetal development and early childhood can have a huge impact in developing Autism.
This poor nutrition, such as a deficiency in zinc can lead to learning and memory impairment. Because of this it is important to make sure that pregnant women are maintaining a diet that balances their zinc concentrations. Aside from nutrition, stress can also increase the risk for autism by weakening the immune system which increases the risk for viral infections that can hinder brain development. Scientists have not found a direct cause of Autism, but being conscience of the environment a child is developing in can greatly reduce the risk of Autism.
It is always hard to admit that there is a limited amount that scientists know about such an important disease, but they are making great progress in the right direction. One thing we can do as the general public is inform ourselves on the disease. Knowledge is a very powerful tool that can be used to help people understand how to interact and be patient with a person who has autism.
Mom and Dad: Our Role in Autism
Mom and Dad: Our Role in Autism
Autism is a developmental disorder that is characterized by impairment in communication and social behavior. But there is no single exact idea for what exactly autism is; it exists as a spectrum from nearly unnoticeable to extremely severe. Because of this, physicians often have a difficult time diagnosing patients as autistic. Also, because autism is a developmental disease, it is first recognized in children when they are most often quite young. As autistic children mature and develop, a range of symptoms can appear such as problems with facial expressions, lack of empathy, repetitive use of language, and preoccupation with certain topics to name a few. For a more comprehensive list of possible symptoms, you can visit the following link: http://www.webmd.com/brain/autism/autism-symptoms.
But what lies at the heart of this disorder? What brings about its cause, and is there a way it can be treated? If we think about the situation, because the disease has its onset so early in the child’s life, I think of a few possible culprits: 1. Genetics, 2. Developmental Issues (either by random chance or by maternal influence in utero), and 3. Early environmental influences after birth. Autism is quite common, and many people have somewhat of an idea about what this disorder is. But there are many new and interesting factors of which most people are unaware!
For this brief article, I want to focus in on the role that “Mom and Dad” might have. I hope to touch collectively on some interesting ideas that you may not have thought of before that may play a role in the onset of autism. However, I will not claim that any of these specific things will certainly cause autism; as a whole, even researchers still are not sure exactly what the overall cause is. Ultimately, it appears that there are many factors in play that there is not necessarily ONE specific cause. Rather, the cause of autism should perhaps be considered a convoluted interweaving web of factors─ the sum of which collectively forms the disorder we have come to describe as autism. But I digress; let’s explore what scientists have learned thus far.
Talking about Dad is short. In development, we know that his role is important, but after conception, there is not much he can do for the development of the baby other than offer his tender love and care, making sure that the mother is comfortable and healthy. Nevertheless, his sperm must contribute half of the genetics to the child. Because men produce sperm continually, there is a small chance for random mutations in the genes to occur in each sperm. As the man ages, these random mutations can accumulate, and the risk for one of them to contribute to autism is therefore increased. On the other hand, females carry all of their eggs and do not produce new ones, so the risk of accumulating mutations is not a factor unless the mutations had been present from birth. So in the case of the mother, the factors that contribute to autism must come from elsewhere.
The mother has an incredibly important role in the development of the child. It is honestly a miracle that her body is able to coordinate the growth of another human being inside of her. With all of the parts and pieces that must be perfectly aligned, it is amazing that it all happens correctly!
During development, a variety of factors such as poor nutrition, bacterial/viral infections, and high stress can all contribute to the risk of autism. How you might ask? Again, we do not know exactly, but I will tell you what we do know so far. In nutrition, zinc is especially important. A zinc-deficiency can lead to neuropsychological symptoms such as learning and memory impairment. In addition, it can also lead to impairment of the immune system. When the immune system of the mother is impaired, the fetus is more at risk for damage from bacterial/viral infections while still in the uterus. In this critical time of development, any problems from outside factors can be detrimental to the baby. Finally high stress placed on the mother can dislodge the equilibrium of the child and may lead to impairment of the child’s immune system. Then, when born, the child can be at higher risk for bacterial/viral infection that can further hinder the child’s brain development.
Overall, it is impossible to place blame on either parent, or on any single factor for being “THE CAUSE OF AUTISM.” We really do not know enough about autism to be sure, and much more research must be done as we move toward a better understanding of the disorder. In the future, I hope that we will come to know an exact cause of autism and how it can be treated. However, in the meantime, it is important to be aware of some of these risk factors as we proceed in attempt to give ourselves the best chances for reducing the prevalence of autism for the future.
Final thoughts on autism written by Steven Dotzler
How Mom and Dad Cause Autism
Autism, a developmental disorder that has its roots in both genetic as well as environmental factors is characterized by learning and social behavior impairments. According to recent research, the environmental factors may be more entangled with the genetic factors than was thought previously. As you might expect, the behavior and lifestyle of an expecting mother has a lot to do with the risks of autism for her unborn child. Less understood, however, is the effect the father has on a child’s risk of developing autism.
Some important environmental factors linked with the mothers health are immune system abnormalities and zinc deficiency. Immune system abnormalities is obviously a negative thing for a pregnant woman as any deficit in her immune system can lead to things like viral infections that can damage the fetus’ neurodevelopment. It can be caused by various different things such as prenatal stress, toxins, melatonin deficiency, and even the age of the mother.
Zinc deficiency may be a little more ambiguous to someone not familiar with studies on autism. Zinc is a metal ion used in many processes in your body and competes for absorption with calcium ions. Low zinc levels have been associated with not only autism but patients with bipolar disorder, eating disorders, and depression as well. Low zinc levels are usually caused by abnormal eating habits such as pica, or the eating of non-nutritive substances. Zinc deficiency and immune system abnormalities are linked by many different factors and are correlated with the genetic factors of autism as well.
Not to put all the blame on mothers, fathers also have some say in the genetic makeup of a child. It was found that the age of the father could have some relation to the risk of autism in the child. As the father ages, genetic mutations in the sperm cells become more and more prevalent. Because autism has a very real genetic component as well as environmental, these mutations don’t bode well for developing fetuses.
Vaccinate Your Children
This week we discussed autism in our neurochemistry course. Most of our discussions have revealed this year that the diseases and disorders in the brain are incredibly complicated. Autism is not, in this sense, an isolated case. It has many complicated genetic causes. Some of these genetic causes come about from mutations called de novo mutations in the father’s germ line. The paper we read discussed many of the environmental factors associated with causing autism. A couple of these include immune system of the mother, zinc deficiency, and stress on the mother during prenatal and perinatal timescales.
I found many of these pathways interesting, but their highly convoluted nature made it hard to formulate a possible plan of attack to combat, cure, or treat autism.
With all this confusion it’s hard to know where to go or what to do about the rising diagnosis of autism. However, what is painfully clear about autism is that vaccination absolutely does not cause autism. This terrible misunderstanding is the vestigial tail of a fraudulent claim made by a scientist in the UK. The ramifications of this claim are incredibly detrimental. In the 20th century mankind, through science, has accomplished unbelievable things such as the eradication of diseases that once plagued humans. These diseases killed many of our ancestors and maimed many more, and we now have the beautiful gift of not even fearing smallpox or polio. The anti-vaccination movement, founded on this ignorant study out of the UK, has sought to bring these diseases back into our society for some odd reason. The authors of the paper we read, and many other scientists, explicitly and in no uncertain terms have repeatedly said that vaccination does not cause autism. So parents, please vaccinate your children.
Putting the Puzzle Pieces of Autism Together
Autism spectrum disorder is the term used to describe a range of neurodevelopmental disorders characterized by communication difficulties, social impairments, and repetitive, restricted, and stereotyped behavior. The U.S. autism rate is currently 1 in 68, though it remains to be determined whether this is due to an increase in prevalence or diagnosis. The severity of autism can range from a milder form, Asperger syndrome, to the most severe form, autistic disorder. Most cases are identified before the age of 3. Hallmark features in infants are unresponsiveness to people or an intent focus on one item with the exclusion of other items for long periods of time. Children with ASD may fail to respond to their own names and avoid eye contact with other people. Additionally, ASD children engage in repetitive movements such as rocking or self-abusive behavior like head-banging or biting. They have difficulty interpreting the thoughts and feelings of others because they do not understand social cues such as facial expressions or tone of voice. A variety of influential factors contributing to the onset of ASD have been identified, though the exact cause of ASD has yet to be determined.
Autism Diagnosis
Below is a list of indicators used in the diagnostic process of autism. Severe cases of autism are usually diagnosed at a much earlier age than milder cases. Asperger’s syndrome, a mild form of ASD, is typically identified by later indicators. Individuals with Asperger’s have relatively normal intelligence and cognitive ability but impaired social functioning. Diagnosis is completed through a comprehensive evaluation by a team including a psychologist, psychiatrist, neurologist, speech therapist, and other professionals involved in ASD diagnosis.
Early indicators
- no pointing or babbling by age 1
- no response to name
- poor eye contact
- loss of social skills or language
- no single words by 16 months or 2-word phrases by age 2
- no smiling or social responsiveness
- excessive lining up of objects or toys
Later indicators
- impaired ability to initiate/sustain a conversation with others
- impaired or absent imaginative or social play
- impaired ability to make friends with peers
- preoccupation with certain objects or subjects
- repetitive, stereotyped, or unusual language use
- restricted patterns of interest with abnormal focus and intensity
- inflexible adherence to specific rituals or routines
Contributing Factors to ASD Onset
Although genetic factors are involved in ASD onset, they only account for 15% of autism cases. Maternal nutrition, infection during pregnancy, prematurity, and parental age are among the environmental factors implicated in ASD. Immune system abnormalities and zinc deficiency also play a role in altered synaptic transmission present in ASD.
- Fetal brain development failures are connected to an increased autism risk. Infections associated with autism include: prenatal influenza, rubella, and cytomegalovirus infections.
- Zinc Deficiency is present in those with ASD. Zinc is the second most abundant trace element in the body, and is implicated in processes such as cell division and differentiation. A deficiency of zinc causes neuropsychological symptoms, memory and learning impairments, behavioral issues, and enhanced glutamate excitotoxicity. Zinc deficiency is also connected to compromising the immune system, which may be connected to prenatal infection risk.
- Abnormal melatonin synthesis may also be implicated in autism. Melatonin is a neurohormone responsible for regulating circadian rhythms, the body’s internal clock involved in regulating the sleep/wake cycle. Low melatonin levels are observed in individuals with ASD. Children with ASD have sleep abnormalities such as frequent interrupted sleep, reduced duration, and prolonged sleep onset latency. The circadian abnormalities ins ASD may be due to genetic abnormalities related to melatonin synthesis.
- Maternal diabetes is another ASD risk factor. Obesity, diabetes, and hypertension have been found to occur more often in mothers of ASD children. Obesity has the most significant association with ASD risk.
- Prenatal stress may also increase ASD risk. Prenatal exposure to stress hormones or psychological stress has been shown in various studies to result in abnormal infant immune function that persisted to late childhood. A high stress environment during the prenatal period can prolong the activation of the HPA axis, which is involved in the body’s stress response. Prolonged HPA activation lowers the immune system’s ability to fight off infection.
- Prenatal exposure to valproic acid, an anticonvuslant has also been implicated in ASD onset. Valproic acid is a medication used to treat epilepsy and bipolar disorder.
- Increased parental age in both the mother and the father are connected to ASD risk. Paternal age is linked to ASD risk due to a greater number of mutations present in older sperm that can increase ASD risk. Maternal age is connected to ASD risk through increased pregnancy complications and autoimmunity.
Take-Home Message
The extensive list of possible contributing factors and recent statistics regarding autism is daunting, but it is important to note that the presence of one factor does not necessarily guarantee ASD onset. The identified factors are implicated in ASD, but their relationship to one another is not fully understood. One ASD factor that has been affirmatively ruled out is vaccination. This is NOT connected to ASD in any way, though this idea still seems to continue to circulate. The researcher who conducted the vaccination study was stripped of all medical practicing abilities after it was revealed that the study and data were fabricated. Individuals with ASD greatly benefit from treatment such as social skills training, speech therapy, and applied behavioral analysis. Some medications can be used for side effects such as obsessive-compulsive disorder or anxiety, though the presence of these side effects vary from one case to another. Hopefully with continued research, we can identify the link between the contributing factors and perhaps determine the cause of ASD.
For more information on autism: http://www.ninds.nih.gov/disorders/autism/detail_autism.htm
http://www.autismspeaks.org/
Sources:
Image link: http://img.washingtonpost.com/news/to-your-health/wp-content/uploads/sites/26/2014/03/1-in-68-graphic-with-logo-296×398.jpg
A Disorder of Growing Uncertainty: Autism
Global rates of autism have been increasing, and although we have identified several genes and environmental factors with development of the disease, the ultimate cause is yet to be determined. One might argue that this global increase in autism rates is due to increased diagnosis and classification of the disease. While this could be true, it is not the whole story.
There have been many different genes associated with autism. Most of these genes are caused by certain mutations that occur within the genome. While parents may not carry the mutation themselves, it is possible for the mutations to occur in their reproductive cells or to the baby during pregnancy. Many different environmental factors have been connected with increased risk of gene mutations. As you can see in the figure below, mutations can be attributed to Mendelian Disorders, rare de novo mutations, and chromosome abnormalities.
The question that is trying to be answered now is what makes up the remaining 77% of genetic mutations? Studies have shown connections between environmental factors during pregnancy and early development and rates of autism. These environmental factors include:
Prenatal Viral Infection: Maternal infection and complication of immune system health during pregnancy has been integrally linked with development of autism.
Zinc Deficiency: Zinc deficiencies have been observed in autistic children. This deficiency could play a large role in gene expression.
Abnormal Melatonin Synthesis: Inability to produce sufficient melatonin has been observed at high rates in autistic patients. This abnormal melatonin synthesis leads to complications in the circadian rhythm, leading to abnormal sleep patterns.
Maternal Diabetes: Maternal diabetes during pregnancy has lead to a twofold increased risk of the child developing autism.
Prenatal and Perinatal Stress: High levels of stress have been associated with increased risk of autism.
Toxins: Many toxins have also been associated with gene dysfunction and the development of autism.
Parental Age: The age of both mother and father have a profound influence on the development of autism. The older the parents are, the more likely complications will occur in pregnancy, leading to autism.
Postnatal Risk factors: Gastrointestinal abnormalities, allergies, exposure to drugs, infection, and heavy metals have also been associated with development of autism after birth.
Many different causes have been proposed, and currently there is no one cause that stands out as the one and only cause to the disorder. Further research must be done to better understand autism and how it can be prevented. However one thing is certain. Vaccination has been discounted as a source of autism. So parents, DON’T HESITATE, VACCINATE!!
Incidence of Autism linked to Stress?
Autism is a neurodevelopmental disorder that is characterized by impairment in communication and social behavior and by repetitive behaviors. Like most any other disease that affects someone for the majority of their life, a large portion of the cause of autism is due to genetic factors but genetics is unable to account for all cases of autism. So this brings up the effects that our environment has and its implications in the onset of autism. The most critical time for the environment to have it effects on an individual causing autism is while the mother is carrying her child during pregnancy. Recent research has shown many imbalances due to environment during pregnancy lead to autism and in particular the mother being stressed.
Normally during pregnancy a woman has elevated levels of cortisol which is the body’s natural stress hormone, but this slight elevation during pregnancy is important for a normal pregnancy. If, for some reason, the cortisol levels of the pregnant woman were to increase to abnormally high levels research has shown that cortisol from the mother that is able to reach the fetus may potentially alter fetal development and growth, which in the case of neurodevelopment could be extremely detrimental. It has been shown that the cortisol levels of pregnant women can increase to abnormally high levels during particularly stressful situations such as major storms or natural disasters. Research has also shown that the placenta is also affected by stress by releasing Corticotropin releasing factor that can cross the blood brain barrier and cause damage to the function and integrity of the hippocampus of the developing fetus. Another stress to the mother that could be harmful to the fetus is sickness. Research has shown that if the mother contracts a virus or bacteria that are able to reach the fetus likelihood of the fetus developing autism is much higher.
After reading this article I think that it is very important to make sure that the environment that a fetus is developing in is as stable and safe as possible to ensure the healthiest offspring possible, but at the same time I don’t think that it is something to be so worried about that people start to panic and quarantine their pregnant woman to prevent disease. If you think about it the fact that there aren’t more diseases or incidence of autism is amazing because there are so many things and ways that things can go wrong in the development of a fetus that a completely healthy newborn is in itself a miracle. I think that is just a testament to how amazing the human body is and well it does what it does.
Autism: An Environmental Perspective
Autism is a spectral disorder that is becoming commonly diagnosed. In fact, 1 in 68 children are diagnosed as part of the spectrum. This brings up the question whether the criteria for diagnosing are becoming fine-tuned and therefore more accurate or whether people are stretching the diagnosis because parents demand an answer to why their child is “different.” Because it is a spectrum disorder, autism includes a broad range of social, behavioral, and cognitive deficits. From high-functioning cases of individuals with high IQs and low social skills to cases where communication is not possible, there is no one way to define autism.
Just as with all facets of development, there is a balance between genetics and environment that plays into expression of hereditary traits. There are a number of genes that predispose an individual to becoming autistic, but what is most interesting is the role of environmental factors. Since most cases of autism of diagnosed in early childhood, it is possible that fundamental structures in the brain are altered while in utero, but are not noticed until key developmental periods. Parents might see cognitive deficits from delayed speech progression, abnormal social behaviors, repetitive behaviors, etc. The phenotype for autism lies in the neurological changes in the brain which include alteration of important synaptic proteins needed for long term potentiation. In addition, autistic individuals have a smaller amygdala and hippocampus. The amygdala is important for emotions, emotional behaviors, and motivation while the hippocampus is important for long-term memory. This week’s article focused on how prenatal environment affects the neurological development of the autistic brain.
The author suggests two central components to environmental factors are immune system abnormalities and zinc deficiencies. Maternal stress is one contributor to the altered immune system and changes within the brain. Specifically, mothers under stress have high levels of cortisol which cross the placenta and alter the neurological development. The small hippocampus of autistic patients also leads to high cortisol secretion which may also contribute to abnormal growth. Parental age of both the mother and father contributes to the increase the risk for autism in the offspring. Mothers over 30 years old are more likely to have an autoimmune disorder. The antibodies of these mothers may inappropriately target the growing fetus during critical periods of development. Fathers have an increased risk of sperm mutations with age. Lastly, prenatal infections such as influenza may cause inflammation of the brain. The other major factor for autism, zinc deficiency, actually plays into the altered immune system because low levels of zinc promotes inflammation and impairs immune responses. In addition, zinc deficiency causes gastrointestinal abnormalities commonly linked to autism.
There are many hypotheses for how these abnormalities lead to autism. The immune system alters long term potentiation, a mechanism required for learning and memory. In addition, pro-inflammatory cytokines can affect neurotransmitter release and the ability to send neurological signals. The modification of NMDA receptors necessary for excitation of the neuron is another possible mode of action. There are many other mechanisms touched on in the paper, but I focused on the immune system mechanisms.
Many factors increase the risk for autism, but there is not a complete understanding of the mechanism. Does a zinc deficiency cause autism, or is it merely a side effect? More research is required to form the complete picture of the genetic and environmental causes. Autism might be diagnosed more and more because parents want a single answer to certain quirks or abnormalities of their child. However, autism might be expressed to greater degree because of our culture. Our generation starts families later in life to allow time to establish their careers. In addition, our fast-paced society may contribute to the stress of mothers, producing a dangerous environment for a fetus. No longer are people in the dark or misinformed about what causes autism. I think education is the first step in understanding autism spectrum disorder and moving towards a better understanding.
Resources:
http://www.autismspeaks.org/what-autism
Obesity: What happens when you can't trust your gut
Obesity is frequently demonized as a disease of laziness – one that people could avoid if they would only get off the couch and eat healthier. Recent research, however, has identified several brain-related components to this disease, possibly enough to categorize it as a brain disorder. While it is true that some individual responsibility is required for overcoming obesity, several other factors must be understood in order to really tackle this issue.
Much of the brain dysfunction that occurs in obesity does appear to come as a result of high-fat diet. Chronic intake of high amounts of fat can inflame and damage some parts of the brain, including the hypothalamus, which controls hunger (among other homeostatic processes, like sleep). Inflammation in the rest of the brain will eventually lead to a cascade of events resulting in loss of memory function. Overconsumption of carbohydrates, another obesity-associated eating behavior, can lead to insulin resistance, which has been shown to have a negative effect on cognition and induces type 2 diabetes. But if an unhealthy diet causes obesity and so many other health issues, how can people not be expected to assume more responsibility for themselves?
First to consider are the social issues linked with obesity. There is the obvious issue of fast food and other generally unhealthy food being usually cheaper than more nutritional food. This especially affects low-income communities: one 2010 study found that BMI and income were inversely related, indicating a correlation of low wages to increased risk for obesity. Not only are there many factors that can predispose people to being obese, but once weight gain begins, it can be hard to go back. This is especially true when exposure to high-fat foods begins early in life. For example, rats exposed to a high-fat diet when nursing or pregnant leads to overweight offspring. Additionally, another study found that when rats are exposed to the same type of diet during the postnatal growth period, they tend to favor high-fat foods in their adult lives, leading to an increase in risk for obesity.
Perhaps the most interesting element involved in obesity is the modulation of metabolism and intestinal signaling by microbiota which naturally occur in the digestive system. Bacteria play a role in the speed by which food is transferred from the mouth through the rest of the gut, an activity which happens more quickly in obesity. This leads to feeling hungry sooner after eating as well as altered absorption of certain nutrients. Interestingly, a study found that by simply transferring bacterial cultures from obese mice to nonobese mice, they developed symptoms associated with metabolic syndrome – one of which is obesity.
Perhaps it can be said that obesity begins with poor nutritional choices – but these choices can be influenced by society and perpetuated by alterations to brain morphology and predisposition to metabolic disorders. By understanding the complexities underlying obesity and how societal pressures, differences in biochemistry, and even nonhuman microorganisms can affect the body’s response to how it handles overnutrition (too many carbs, too much fat, etc.), we can begin to make obesity more about personal medicine rather than personal morality. After all, we don’t treat depression as the result of an unwillingness to be happy; while this can perpetuate the illness, it is accommodated for and worked around in current therapies. If obesity could be resulting from a combination of effects not directly related to personal choice, why can’t we treat it the same way?
For more information on gut bacteria, a great summary can be found here.