The brain function that underlies anxiety and depression is inherited, a new study finds — but there is still plenty of space for experience and environment to reduce the risk of a full-blown mental disorder.
The research focused on rhesus monkeys. Like humans, some young rhesus monkeys have what’s called an “anxious temperament.” Expose them to a mildly stressful situation, like being in a room with a stranger, and the monkeys will stop moving and stop vocalizing while their stress hormones skyrocket. Extremely shy children do the same, said Dr. Ned Kalin, a psychiatrist at the University of Wisconsin–Madison.
Kalin and his colleagues scanned the brains of young monkeys, anxious and not, and found three brain regions associated with anxiety that also showed evidence of heritability. About 30 percent of the variation in early anxiety is explained by family history, the researchers reported Monday (July 6) in the journal Proceedings of the National Academy of Sciences.
Anxiety and depression are widespread disorders. According to the National Institute of Mental Health (NIMH), about 18 percent of U.S. adults have experienced an anxiety disorder in the past year, and about 7 percent have had a major depressive episode. The average age of onset for anxiety disorders is 11.
Kids with extremely anxious temperaments are at a 50 percent risk of developing a mental disorder later in life, Kalin told Live Science. He and his colleagues are trying to figure out the brain basis of this temperament, in hopes of developing early interventions that can nudge kids away from anxiety and depression.
The researchers used PET scanning to image the brains of 592 young rhesus monkeys at the Wisconsin National Primate Research Center. These monkeys are raised in pairs at the center and vary in their levels of anxiety, Kalin said.
During the scanning, a stranger entered the room and did not make eye contact with the monkey. This is a mildly stressful scenario for the monkeys, enabling the researchers to watch what happens in the animals’ brains during an anxiety-inducing encounter.
(Animal rights activists and others have criticized and even tried to stop Kalin’s work with rhesus monkeys, though at least one petition against his research has erroneously suggested that Kalin subjected the monkeys to extreme stress and solitary confinement, according to the University of Wisconsin–Madison’s response to the petition.)
Because the researchers know exactly how all the monkeys in their colony are related, they were able to trace the inheritance of anxious behaviors through the family tree. They found that 35 percent of the variation in anxiety could be explained by the genes passed down by mom and dad.
But the researchers took this finding one step further. They looked at specific brain regions that activated during stressful situations, and then matched those up with brain regions whose structure and function were inherited in the same pattern as the anxiety. They found that structure did not seem to affect an anxious temperament. But the function of three brain regions was both heritable and involved in anxiety.
The first, the orbitofrontal cortex, sits behind the forehead and is the most evolutionarily advanced part of the brain, Kalin said. The next was the amygdala, an almond-shaped region deep in the middle of the brain that is involved in fear and emotion. The third was the limbic system, which sits at the very base of the brainstem and is a part of even the most primitive reptile brains.
“What we find is more activity” in the anxious brains, Kalin said. It’s as if the parts of the brain that have evolved to deal with normal threats have gone supercritical, responding to mild threats as if they were major, he explained.
“We believe that our study shows that the overactivity of that system is inherited from our parents,” Kalin said. This overactivity may then leave a person vulnerable to developing depression and anxiety later. But given that nearly 70 percent of the variation in risk of these disorders is not genetic, there is a lot of hope for treatment and intervention, Kalin said.
“This now focuses us on very early childhood, to be thinking about alterations in brain function in children and ideally to be developing ideas that are new about what we can do to help kids that have this brain overactivity,” Kalin said.
The next step is to continue using rhesus monkeys to understand the brain systems and molecular interactions that lead to hyperactive fear regions, he said. The researchers are also following young children over a period of years, scanning their brains to determine what makes the difference between the half of anxious-temperament children who develop a mental disorder and the half who don’t. A separate line of research has already found that a secure attachment to a caregiver helps prevent later mental disorders for extremely shy kids.
“These are very serious illnesses that are common and affect lots and lots of the population,” Kalin said. “We need to understand better what causes them, what the genetic underpinnings are and come up with new treatments to reduce suffering and hopefully do this early in life.”
Follow Stephanie Pappas on Twitterand Google+. Follow us @livescience, Facebook& Google+. Original article on Live Science.
- Anxiety: Hereditary brain chemistry explored
- Anxiety networks unraveled
- Heritable connectivity
- Anxiety is caused by behavior, not genes
- Genes, Depression, and Anxiety
- Anxiety Disorders
- Is Anxiety Genetic?
- Is it Nature or Nurture?
- The Power of Behavioral Inhibition
- Anxiety, Learning Theory and the Role of Environment
- More Research is Necessary
- Seven New Genes Linked To Anxiety Disorders
- Genetics of anxiety disorders: Genetic epidemiological and molecular studies in humans
Anxiety: Hereditary brain chemistry explored
By investigating the brains of hundreds of genetically related monkeys, researchers have identified the brain regions and networks involved in anxiety. They have also shown that changes in connectivity between them are heritable.
Share on PinterestA new study investigates the heritability of anxiety.
Anxiety disorders are a considerable global concern. Affecting almost 1 in 5 adults, they can significantly impact an individual’s quality of life.
Characterized by intense feelings of worry, anxiety disorders can also produce physical symptoms, such as an increased heart rate and shaking.
As with many disorders of the mind, little is known about the nuts and bolts — for example, which cells, regions, and pathways are to blame. Because of this, medications tend to attack the symptoms rather than the source of the issue.
A recent study helps pad our understanding of the brain chemistry behind anxiety disorders; it forms another rung in the ladder toward better treatment.
Building on previous findings, researchers from the University of Wisconsin School of Medicine and Public Health in Madison investigated anxiety in a population of almost 400 rhesus monkeys. Using MRI scanning technology, they shine a light on the dimly lit pathways involved in anxiety. Their results were published recently in the journal JNeurosci.
Anxiety networks unraveled
The scientists, led by Dr. Ned Kalin, focused on behavioral inhibition and anxious temperaments that appear at a young age. These traits are of interest because they strongly predict the development of anxiety disorders later in life.
Understanding the basis of these characteristics could offer insight into how and why anxiety disorders develop.
In earlier MRI-based studies, Dr. Kalin and his team pinpointed brain networks that play a part in producing overly anxious behavior. Of particular note is the central extended amygdala, which is part of the brain’s reward system; this network encompasses an array of nuclei, all of which connect to the amygdala.
Two of the primary divisions of the central extended amygdala are the central nucleus of the amygdala (Ce) and the bed nucleus of the stria terminalis (BST). Metabolism in these tightly interconnected regions has been correlated with variation in anxious temperament; in other words, the amount of activity in the Ce and BST predicts how anxious a particular person will be.
To investigate further, the researchers first assessed each young primate’s natural anxiety level; they did this by exposing them to a human intruder and noting their behavior — more anxious individuals moved around less and made fewer vocalizations. The scientists also measured cortisol levels as a measure of stress.
As expected, monkeys with higher levels of anxiety were found to have increased activity in the Ce and BST.
The animals used in the study came from the same pedigree and were, therefore, all related to different degrees. Because their breeding had been carefully documented, the investigators knew who was related to whom and how closely. This allowed the team to calculate how heritable anxiety is and whether the heritability matches up with changes in brain activity.
They found that the levels of connectivity between the Ce and BST were, indeed, strongly heritable; as the authors explain:
“In the current study, co-heritability analyses demonstrated that Ce-BST functional connectivity and are passed down the family tree together , supporting the hypothesis that Ce-BST functional connectivity and share molecular underpinnings.”
These results support the theory that interplay between the Ce and BST are important in trait anxiety; they also add further evidence that anxiety is heritable and point to new avenues of research.
Although no new treatments for anxiety disorders will come directly from these findings, it is a step forward. Because early-life anxiety predicts mental health in later life, understanding how it develops could be an important step toward intervening and preventing it from developing further.
Anxiety is caused by behavior, not genes
Written by: Jim Folk.
Medically reviewed by: Marilyn Folk, BScN.
Last updated: April 9, 2019
It’s because of our behaviors, not a genetic predisposition
Too often we hear people say, “Anxiety runs in my family, so I guess I just have to learn to live with it.” Or, “My doctor said my anxiety disorder is caused by my family’s genes and I need to take medication to manage it.”
Fortunately, both of these statements are untrue. Yes, it is true that anxiety often runs in families, but that’s because of learned behavior, and not because of genes.
Anxiety is caused by the way we’ve learned to live in unhealthy ways, thus more fearfully and stressfully than others. And since we live more fearfully and stressfully than others, our bodies become more stressed than others, and therefore symptomatic. And since anxiety personalities are notorious worriers, our worry about our symptoms often fuels the anxiety fire.
But since we have learned to live more anxiously than others, we also can learn to live less anxiously, too. Identifying and addressing the unhealthy behaviors at the root of our anxiety is key to eliminating anxiety as a disorder and its symptoms.
So, no one needs to suffer with or put up with an anxiety disorder. Anxiety disorder is fully reversible with the right information, help, and support. Normal health is available to anyone willing to do the work required to learn to live healthier. And this is great news for anyone tired of living with an anxiety disorder.
NOTE: Genes are turned on and off by the way we behave and react to our environment. So just because we have a genetic code doesn’t mean that our destiny is “hardwired.” Quite to the contrary, our behaviors have great influence over what our genes do. As Dr. John Krystal, editor of Biological Psychiatry, stated, “Genetics is not destiny.”
For more information, see our “Anxiety is caused by a genetic predisposition myth”.
Recent study finds web-based technologies revolutionizing mental health care.
A recent study by Dr. Sam Ozersky, a psychiatrist with the mood disorders clinic at the University Health Network in Toronto, found that online self-help materials are revolutionizing mental health treatment and care. He also found that getting psychotherapy online—at a distance removing the need to go to a caregiver’s office—is also changing the face of treatment and care.
“Unless the diagnostic couch is strategically placed beneath a computer screen, it’s rapidly moving to extinction,” Dr. Ozersky says.
Carole Sinclair, director of treatment services at the Hincks-Dellcrest Treatment Centre in Toronto, agreed that e-mental health is the way mental health services will be delivered in the future. “I don’t think we’ve begun to understand the potential of the Web for improving mental-health services.” Dr. Sinclair, also chairs the ethics committee of the Canadian Psychological Association.
Since we’ve been using this approach for the past 13 years, it’s nice to see others in the health communities discovering the same kinds of advantages.
“There are a lot more upsides than downsides and we’re just beginning to understand how much we can do online,” said Dr. Sinclair. “The potential is so great that it’s almost unethical to not pursue this avenue.”
We agree. The successes we’ve seen using web-based self-help information coupled with therapy delivered at a distance have been remarkable. The results we’ve seen far outpace traditional methods.
With today’s technologies, accessing good help is available to anyone no matter where they live. As long as they have an Internet connection, they can access the best help available, and often at a reduced cost. It’s exciting to see so many people get the help they need from those who truly understand anxiety disorder and know how to resolve it. Now, there’s no reason to suffer needlessly!
Click the link for more information about the most effective way to overcome anxiety disorder.
“I can’t express enough gratitude for the amazing help I have received through Doug Wildman and the resulting transformation I have been going through with assistance from the member’s area of the anxietycentre.com website. My life has changed forever and I am finally turning into the person that I always wanted to be…and the person I never thought I could be.” – N.F., Canada
Read more about a recent testimony we received.
For more information about anxiety symptoms, see our Anxiety Symptoms section.
Return to Anxiety Tips.
For a more detailed explanation about all anxiety symptoms, why symptoms can persist long after the stress response has ended, common barriers to recovery and symptom elimination, and more recovery strategies and tips, we have many chapters that address this information in the Recovery Support area of our website.
The combination of good self-help information and working with an experienced anxiety disorder therapist is the most effective way to address anxiety disorder and its many symptoms. Until the core causes of anxiety are addressed – the underlying factors that motivate apprehensive behavior – a struggle with anxiety disorder can return again and again. Identifying and successfully addressing anxiety’s underlying factors is the best way to overcome problematic anxiety.
- For a comprehensive understanding of: Anxiety Disorders Symptoms & Signs, Types, Causes, Diagnosis, and Treatment.
- Anxiety and panic attacks symptoms can be powerful experiences. Find out what they are and how to stop them.
- How to stop an anxiety attack and panic.
- Free online anxiety tests to screen for anxiety. Two minute tests with instant results. Such as:
- Anxiety Test
- Anxiety Disorder Test
- OCD Test
- Social Anxiety Test
- Boundaries Test
- Anxiety 101 is a summarized description of anxiety, anxiety disorder, and how to overcome it.
Return to our anxiety tips page.
Genes, Depression, and Anxiety
While it’s natural for everyone to feel sad or nervous from time to time, individuals should seek help if they are experiencing profound sadness and intense nervousness for a long period of time. There is no exact science that prescribes either when someone should get over the loss of a family pet or when a person should stop fretting over an impending public speaking gig. In either case, individuals should not allow depression and anxiety to paralyze them.
Often times, what starts off as a few days of feeling sad or anxious can balloon into weeks, months, or even years of depression or anxiety. Without developing the appropriate coping mechanisms that allow you to acknowledge, accept, and manage problems, you are likely to develop anxiety and depressive disorders. Although some people with anxiety and depression can function in the beginning, the symptoms of these disorders will eventually affect their careers, health, and social lives.1,2
Factors that contribute to feelings of anxiety and depression are only the tip of the iceberg. So what’s really going on beneath that humdrum disposition?
Why So Glum?
Although depression is a mood disorder, anxiety is not. Rather anxiety affects your mood secondarily by causing you to worry excessively. Despite depression and anxiety being separate conditions, many of their symptoms—fatigue and decreased energy, sadness and nervousness, poor concentration, and trouble sleeping—overlap. So depression and anxiety occur more frequently together than they do in isolation.3
Of the precipitating factors that cause anxiety and depression, chemical imbalances in the brain is a big problem. Genes that produce mood-enhancing neurotransmitters are switched off by epigenes that are chemical tags serving as an intermediary between genes and the environment. Epigenes have the ability to turn on or turn off gene segments in ways that promote health or facilitate disease. Because of faulty chemical signaling in the brain, neural circuits go awry and lead to depression and anxiety. Which is why many antidepressant and antianxiety medications target certain neurotransmitters (brain chemical messengers). Here are some of the neurotransmitters that affect mental health:
Serotonin (5-HT) has analgesic effects and controls sleep, appetite, and mood. Research shows that 5-HT plays a role in the control of mood, depression, and even suicide.
Norepinephrine is a neurotransmitter that affects the cardiovascular system by constricting blood vessels and increasing blood pressure. It also appears to be involved in motivation and reward. Low levels have been linked to anxiety and depression.
Dopamine, an important neurochemical necessary for movement, affects motivation. It’s also plays a role in the brain’s reward center and may trigger substance abuse issues. In postmortem studies, dopamine levels were significantly deficient in the brains of those who had a diagnosis of severe depression.4
Gene Changes That Modify Your Mood
Epigenes are inheritable and environmentally modifiable tags. This is demonstrated largely in part by studies using identical twins who despite having the exact same genes develop epigenetic variations over the course of their lives.5
Stress is a normal bodily response that is good; it helps us to respond appropriately to danger or motivate us. Yet, when stress is persistent, it can lead to emotional problems such as anxiety and depression. Studies also show that stress can be transmitted transgenerationally through epigenetic changes.6 For example, glucocorticoid receptors (GCR) play a role in regulating stress hormones. And researchers found that depression during pregnancy led to highly methylated GRC genes (methylation is an epigenetic change that silences genes).7 In infants, the increase in methylation resulted in an excessive release of stress hormones in times of stress. These epigenetic modifications occurred in the fetus in response to maternal stress and continued well into the child’s adolescent years. Interestingly, weakened GCR activity has been linked to depression and obesity.
People with major depression disorder (MDD) often suffer from poor sleep and now researchers have made progress in figuring out why this happens. By examining the human brain tissue of non-depressed and depressed individuals, researchers were able to identify that the circadian-related genes were disrupted in the brain tissue of those who had a diagnosis of MDD.8 Using gene expression activity in the tissue, the scientists predicted the time of death (TOD) for depressed and non-depressed people and compared the time to the actual time of death. While the TOD was accurately estimated in those without depression, the time in those with depression was significantly off. In fact, the circadian rhythmic genes exhibited nighttime patterns in the daytime and vice versa.
Boost Your Mood
Poor sleep and stress are risk factors for depression and anxiety. But food, however, can vastly improve mood. In my latest book, The Gene Therapy Plan, which is scheduled for release in April 2015, I offer healthful dietary tips to elevate mood and control anxiety. These tips are backed by science-based medicine that I’ve been using for over 20 years to treat my patients. The following are some foods to elevate your mood:
Watermelon, which ranks 34 out of 51 fruits and vegetables listed on the Environmental Working Group’s (EWG) pesticide list, contains loads of vitamin B6—a nutrient involved in regulating mood and sleep.
Apples rank No. 1 on the EWG list; however, you shouldn’t forgo eating them. Apples contain a compound that is an essential anti-inflammatory agent and helps to maintain healthy brain function—quercetin. Whenever feasible, opt for organic fruits and vegetables. If buying organic produce isn’t always an option for you, don’t skip out on eating fruits and vegetables. Instead take special care in washing any fruit and vegetable you buy.
Eggs are a good source of protein and contain amino acids that produce dopamine.
Honey increases insulin. The hormone allows tryptophan—an amino acid in certain foods that promotes sleep and relaxation—to enter the brain readily.
Asparagus is a good source of folate. Low folate levels have been linked to depression. Alternatively, try these other folate-rich foods: spinach, turnip greens, broccoli and Brussels sprouts.
Green tea contains mood-boosting phytochemicals such as theanine, which has a calming effect and promotes concentration and focus.
Turkey contains tryptophan; it’s an amino acid involved in the production of melatonin and other sleep-related chemicals in the body. Other sources of tryptophan include chocolate, chickpeas, and chicken.
Vitamin D3 enhances mood and energy. Low vitamin D levels aren’t that uncommon. Because sun exposure is the best way to get vitamin D, this becomes increasingly more difficult during the months in which daylight is less. Foods that contain vitamin D are eggs, mackerel, salmon, and tuna. Since most people are deficient in vitamin D, ask your doctor to check your levels.
Other mood-enhancing activities include physical activity and meditation. Next time you’re feeling stressed, depressed, or anxious, try going for a walk or hike, socialize with friends or family, get lost in a hobby, or soak in a nice warm bath.
1. Mendlowicz MV, Stein MB. Quality of life in individuals with anxiety disorders. The American journal of psychiatry. 2000;157(5):669-682.
3. Bakish D. The patient with comorbid depression and anxiety: the unmet need. Journal of Clinical Psychiatry. 1999.
4. Dunlop BW, Nemeroff CB. THe role of dopamine in the pathophysiology of depression. Archives of General Psychiatry. 2007;64(3):327-337.
5. Fraga MF, Ballestar E, Paz MF, et al. Epigenetic differences arise during the lifetime of monozygotic twins. Proceedings of the National Academy of Sciences of the United States of America. 2005;102(30):10604-10609.
6. Pembrey M, Saffery R, Bygren LO, et al. Human transgenerational responses to early-life experience: potential impact on development, health and biomedical research. Journal of medical genetics. 2014:jmedgenet-2014-102577.
7. Radtke KM, Ruf M, Gunter HM, et al. Transgenerational impact of intimate partner violence on methylation in the promoter of the glucocorticoid receptor. Transl Psychiatry. 2011;1:e21.
8. Li JZ, Bunney BG, Meng F, et al. Circadian patterns of gene expression in the human brain and disruption in major depressive disorder. Proceedings of the National Academy of Sciences. 2013;110(24):9950-9955.
What is an anxiety disorder?
Anxiety is a normal human emotion. Many people feel anxious, or nervous, when faced with a problem at work, or before taking a test or making an important decision. Anxiety disorders, however, are different. They can cause such distress that it interferes with a person’s ability to lead a normal life.
An anxiety disorder is a serious mental illness. People with anxiety disorders respond to certain things or situations with fear and dread, as well as physical signs of anxiety such as a pounding heart and sweating. For people with anxiety disorders, worry and fear are constant and overwhelming, and can be crippling. An anxiety disorder is diagnosed if the person’s response is not appropriate for the situation, if the person cannot control the response or if the anxiety interferes with normal functioning. Anxiety disorders can get worse if not treated; however, effective treatments are available.
What are the types of anxiety disorders?
There are several recognized anxiety disorders, including the following:
People with this disorder have feelings of terror that strike suddenly and repeatedly with no warning. Other symptoms of a panic attack include sweating, chest pain, palpitations (unpleasant sensations of irregular heartbeats) and a feeling of choking, which might make the person feel like he or she is having a heart attack or “going crazy.”
Post-traumatic stress disorder (PTSD)
PTSD is a condition that can develop following a traumatic and/or terrifying event, such as a sexual or physical assault, the unexpected death of a loved one, or a natural disaster. People with PTSD often have lasting and frightening thoughts and memories of the event, and tend to be emotionally numb.
Social anxiety disorder
Also called social phobia, social anxiety disorder involves overwhelming worry and self-consciousness about everyday social situations. The worry often centers on a fear of being judged by others, or behaving in a way that might cause embarrassment or lead to ridicule.
A specific phobia is an intense fear of a specific object or situation, such as snakes, heights or flying. The level of fear usually is inappropriate to the situation and might cause the person to avoid common, everyday situations.
Generalized anxiety disorder
This disorder involves excessive, unrealistic worry and tension, even if there is little or nothing to provoke the anxiety.
How common are anxiety disorders?
Anxiety disorders affect about 40 million adult Americans. They are the most common mental illnesses in the U.S. Most anxiety disorders begin in childhood, adolescence and early adulthood. They occur more often in women than in men.
What causes anxiety disorders?
The exact cause of anxiety disorders is not known; but anxiety disorders — like other forms of mental illness — are not the result of personal weakness, a character flaw or poor upbringing. As scientists continue their research on mental illness, it is becoming clear that many of these disorders are caused by a combination of factors, including biology and environmental stresses.
Like certain illnesses, such as diabetes, anxiety disorders might be caused by chemical imbalances in the body. Studies have shown that severe or long-lasting stress can change the balance of chemicals in the brain that control mood. Studies also have shown that anxiety disorders run in families, which means that they can be inherited from one or both parents, like hair or eye color. In addition, certain environmental factors — such as a trauma or significant event — might trigger an anxiety disorder in people who have an inherited susceptibility to developing the disorder.
What are the symptoms of an anxiety disorder?
Symptoms vary depending on the type of anxiety disorder, but general symptoms of anxiety include:
- Feelings of panic, fear and uneasiness
- Uncontrollable, obsessive thoughts
- Repeated thoughts or flashbacks of traumatic experiences
- Ritualistic behaviors, such as repeated hand washing
- Problems sleeping
- Cold or sweaty hands
- Shortness of breath
- An inability to be still and calm
- Dry mouth
- Numbness or tingling in the hands or feet
- Muscle tension
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Is Anxiety Genetic?
As a therapist, I often work with many clients who live with anxiety. That should come as no surprise as anxiety disorders are among some of the most common mental health conditions, especially in the United States. Around 40 million people deal with an anxiety condition annually. One question that comes up from time to time is, “is my anxiety genetic?”
Is it Nature or Nurture?
In many circles, the question of whether anxiety is genetic or mostly environmental (nature vs. nature) comes up often. The nature versus nurture conversation is one that I’ve been exposed to since I was first exposed to psychology.
There are some who place a great deal of emphasis on biology. They believe that we are most often at the whims of our genetic coding. Others believe that life experiences and difficult circumstances are primarily responsible for our development of anxiety conditions. However, most of the research, and most providers will likely tell you, for most people developing an anxiety condition is a mixture of both nature and nature.
It’s not uncommon for me to have conversations with clients when I’m gathering family history where I believe that a client may have inherited some of the anxious traits of their parents. It’s relatively common, in fact!
However, that also has to take into account that most children live with their parents for many years, often witnessing and learning their parents’ ways of engaging with the world. This can often include what their parents find frightening or anxiety provoking. Anecdotally, it’s hard to decipher between whether nature or nature is in the driver’s seat. Research has, and continues to, make some ground in answering the question.
What Science Says About the Genetics of Anxiety
Twin studies on anxiety disorders demonstrate a genetic foundation for developing an anxiety condition. That is, there is some belief that anxiety conditions do run in families, suggesting relatively strong genetic relationships. Some research of Generalized Anxiety Disorder indicates a “moderate genetic risk” at 30%.
However, the findings on specific gene-mapping have been less clear. This has led researchers to believe that there may be many different genes responsible for the development of anxiety conditions such as Generalized Anxiety Disorder or Panic Disorder (Villafuerte & Burmeister, 2003). Gene-mapping is still a very new field of study in medicine, therefore the research community expects to have more valuable findings as more studies are conducted in the future.
The Power of Behavioral Inhibition
One significant finding in research states that there are some personality or temperamental characteristics that are more commonly genetically transferred or inherited through families.
One example is behavioral inhibition. The belief is that anxiety-motivated behavior often manifests as avoidance, stress, and withdrawal in unfamiliar situations and with unfamiliar people. Theorists state that for the 15-20% of the children who demonstrate this kind of behavior, they are at increased risk for anxiety disorders (Ollendick, Shortt, & Sander, 2008). The research also indicates that those children with more extreme reactions in these unfamiliar situations may be at higher risk for a clinical diagnosis, suggesting a strong genetic predisposition being exacerbated by certain settings and environments.
Anxiety, Learning Theory and the Role of Environment
On the other hand, anxiety researchers also cite social learning theory as a significant contributor or nexus to the development of clinical anxiety conditions (Ollendick, Shortt, & Sander, 2008). There are mainly four ways in which the development of anxiety is explained:
- That fear and anxiety can be learned through being exposed to some traumatic event and that event being connected to some previously neutral experience (eg. being bit by a dog after having neutral experiences with dogs before)
- People learn anxiety and fear through watching the reactions and experiences of those around them (modeling)
- Fear or anxiety may be exchanged just by talking about situations, objects or people
- Through avoidance, children may negative reinforce anxiety symptoms over time leading to the development of a clinically significant anxiety condition
As you can see here, the question of “is anxiety genetic?” is about as easy to answer as “What came first, the chicken or the egg?” Further research must be done in order to sufficiently answer the question definitively whether anxiety conditions are genetic or not. That being said, the most recent research on genetic mapping is promising for determining predisposition for certain health conditions.
More Research is Necessary
One flaw of the research out there is that it’s been difficult to gather large enough populations to adequately study and sample such a wide range of conditions. There are many disorders that fall under the umbrella term of anxiety conditions. In order to have a better understanding of the nature of these illnesses, many more people will need to participate in research. With this, hopefully we will be better able to accurately assess whether anxiety is genetic or not and identify the best strategies in treatment overall.
Seven New Genes Linked To Anxiety Disorders
Researchers have linked seven new genes to anxiety disorders such as obsessive compulsive disorder, panic disorder and social anxiety disorder.
These gene links mean that new drug treatments could be created to target these gene products specifically in the treatment of anxiety disorders. It gives hope to thousands of people who currently have no treatment plan.
Treatments for anxiety disorders involve both drug-free and drug-based therapies. The most effective treatment strategies are a combination of the two, differing in application from patient to patient.
To treat these conditions using drug-based therapies, drugs have been designed to target specific genes which produce proteins associated with the progression of disorders. Because these disorders are so complex, gene discovery is difficult.
Currently, there are only two core pathways that are associated with drug-based therapies: the dopaminergic and the serotonergic pathways. Dopamine changes have been linked to movement, motivation, reward-response and addiction. Serotonin in the brain has been linked to mood, social behaviour, memory and cognitive function.
Drug-based therapies work on roughly half of those affected and treated, leaving a large number of people without tangible assistance. The current treatments for anxiety disorders are not as effective as hoped. A better understanding of why and how these disorders exist is essential for better treatment strategies.
Looking At Novel Gene Targets
Our research uncovered several new genes that could potentially play roles in how anxiety disorders develop and progress. We used an interdisciplinary approach on both animals and people to uncover these genes.
To help us identify the candidate genes, we focused on the striatum section of the brain in which the synaptic plasticity pathway was chosen. In neuroscience, synaptic plasticity refers to the ability of synapses (connections in the brain) to strengthen or weaken over time in response to a stimulus. The striatum helps co-ordinate motivation with body movement. It can be as simple as fine-motor function or as complex as behavioural inhibition depending on social interaction.
The result was that we identified seven new genes as possible candidates for further study. Six of these genes have never been implicated in anxiety disorders before.
To date, global research has identified a number of risk factors for anxiety disorders. These can be grouped into two categories: genetic factors and environmental factors. Genetic factors relate to differences in one’s genetic code that either protect or put you at risk for developing anxiety disorders. Environmental factors include childhood trauma and substance abuse.
To further complicate things, these categories tend to interact with one another. Scientists believe the interaction is what results in a plethora of differences among patients even when they have the same disorder. For example, two people may have severe obsessive compulsive disorder and be on the same treatment schedule. Due to the differences in their genetic make-up and lifestyles, they could respond differently to treatment.
Drug-based therapies only work for half of the people suffering from anxiety disorders.
Some of these candidates also appear to interact with environmental stressors. Trauma experienced during early developmental years has been thought to be a risk factor for anxiety disorders for a number of years now. It is believed to be a key factor in the variation seen among different patients.
Although this theory is difficult to investigate and depict, it was possible using the strict and specific conditions that we did. The finding provides a precedent for future work to try and better understand how the environment interacts with genetics to manifest in disease.
Anxiety disorders such as obsessive compulsive disorder, panic disorder and social anxiety disorder are among the most severe and debilitating conditions. They currently affect up to 350 million people worldwide.
Despite this disease burden, they have not achieved the visibility, attention or funding they comparatively deserve. For example, the US allocated (in millions) $3920 to cover all brain disorders research for the 2015 financial year. HIV, with an incidence rate well below anxiety disorder – let alone brain disorders in general – received $3000 (in millions).
Myths, fear and stigma are the persistent barriers in the understanding of mental illness. It also hampers public awareness. As a result, as history has shown, those who suffer from mental health illnesses have been ostracised in communities, treated with prejudice and considered second-class citizens.
The Way Forward
By uncovering these new candidates genes – involved not only in risk, but environmental interplay – there is new hope for better and improved treatment strategies.
But whether it is by realising new drug targets, a better understanding at a molecular level or how one’s environment influences disease, a small – yet promising – arsenal of candidates could shed a little more light on a rather dimly lit road.
Nathaniel McGregor is Postsdoctoral Researcher, Department of Psychiatry and Department of Genetics at Stellenbosch University.
This article was originally published on The Conversation. Read the original article.
Genetics of anxiety disorders: Genetic epidemiological and molecular studies in humans
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