There is no one cause for anxiety but several factors that contribute to its development. Scientists have broken them down into three parts: brain chemistry, heredity, and life experiences.
Scientists and researchers are learning more about the factors that cause the development of an anxiety disorder. With new technologies and with more awareness of anxiety disorders, experts can learn more about the psychological and biological effects along with the development of an anxiety disorder.
The following are thought to be triggers for anxiety:
- Brain Chemistry
- Life Experiences
Anxiety Causes: Brain Chemistry and/or Chemical Imbalance:
In a large number of cases, individuals with symptoms of anxiety disorders are usually prescribed medications that change or alter the chemicals of the brain. Because symptoms of anxiety disorders are, in most cases, helped by medication, experts believe that brain chemistry seems to play a part in the trigger of anxiety disorders.
Chemical messengers, or Neurotransmitters, in the brain that regulate thought and feeling sometimes have a problem with brain messages sent out because of a chemical imbalance. Two of the primary neurotransmitters that affect thought and feeling are serotonin and dopamine. When these chemicals have an imbalance, one can feel depressed or anxious.
Scientific evidence tells us that anxiety-related problems such as stress, panic, and exaggerated fears are the result of a imbalance between the right and left hemispheres of the brain. Positron emission tomography or (PET) scans are being done to study this evidence.
Anxiety Causes: Heredity and/or Genetics:
There is evidence that anxiety disorders run in families. If parents or other close relatives have an anxiety disorder, children are at higher risk of developing an anxiety disorder in the future.
Being raised in a family where fear and anxiety are shown on a constant day to day basis can affect a person in adulthood. The brain and its learned behavior is inherited which is reason enough to believe anxiety is heredity. By changing the way one thinks, and changing thought patterns with Cognitive Behavior Therapy, one can overcome anxiety.
Anxiety Causes: Life Experiences:
Researchers believe that the relationship between anxiety disorders and a life of abuse, violence, or poverty is grounds for further study, as these life experiences may affect an individual's exposure to these disorders. Experts believe that anxiety is a learned behavior that can be unlearned. Events in childhood may lead to certain fears that, over time, develop into a anxiety disorder.
In some cases anxiety can be triggered by caffeine, cocaine, and amphetamines. It is a known fact that cocaine use over time can cause feelings of panic, and this terror often continues for years after the drug is stopped. Exhaustion and other stimulants, and even the side effects of certain medications can cause the symptoms of anxiety. Being taught to hold back negative feelings such as anger, or an excessive need for approval, can also be possible triggers.
However, there may be no clear reason why a person feels anxious. It could be a combination of one's personality, the things that have happened to them, or life-changes such as pregnancy, a new job, or loss of a loved one.
Lack of control over life events
Some people who have the symptoms of anxiety have feelings of being out of control. This might be due to rising debts, along with work or study pressures. For another, anxiety could stem from a stressful situation or experience.
Experts in the United States say the results of a study with mice suggests that stress in itself may cause anxiety and depression.
Harvard study of stress hormones
The neuroscientists from Harvard Medical School and Mclean Hospital have shown that long-term exposure to stress hormones such as cortisol and a corticotropin-releasing hormone in mice results in the anxiety that often comes with depression. Such hormones can help the response to an immediate threat.
They believe their findings support circumstantial evidence linking stress and depression, and may be the cause of some mood disorders They say the findings are important for understanding the causes of anxiety and improving the treatment of depression.
Scientists are already aware that many people with depression have high levels of cortisol, a human stress hormone, but it has always been unclear whether that was a cause or effect. This study appears to show that long-term exposure to cortisol exacerbates the symptoms of depression. Researchers Paul Ardayfio, BSC, a graduate student in molecular neurobiology, and Kwang-Soo Kim PhD made their discovery by exposing mice to both short-term and long-term durations of the stress hormone in rodents, corticosterone.
In the study the researchers gave 58 mice the hormone in drinking water so as not to confuse the results with the stress of injection. Chronic doses were 17 to 18 days of exposure; acute doses were 24 hours of exposure.
The mice were put through two tests; in one, mice in a dark part of a cage got the chance to explore a bright, open part of a cage and it was found that the mice that drank the spiked water on a daily basis were more hesitant to enter the exposed space. The researchers interpreted that hesitancy as anxiety.
In the other test, the researchers exposed the mice to a high-frequency sound and the mice under constant corticosterone exposure rather than having an exaggerated reaction had a dulled reaction to that sound the first 10 times they heard it. It suggests that constant exposure to the stress hormone may have depressed the mice, dimming immediate reactions and left them less able to handle a stressful event.
The authors believe this is the first experiment to compare the effects of chronic corticosterone with the effects of acute corticosterone on anxiety-like behavior.
Other evidence for a link between hormones and anxiety
Other evidence has linked depression and anxiety to a disruption in the hormonal system so the findings are not a complete surprise.
Fifty percent of those with Cushing's disease, where the adrenal system releases too much cortisol, have depression and anxiety and the "anxious-retarded" subtype of depression is commonly associated with disruption of that same hormonal system.
People receiving corticosteroid therapy for inflammatory and other disorders have increased mood-related side effects, including anxiety and depression and higher glucocorticoid levels for chronic periods have been linked to increased activity in anxiety related brain regions such as the amygdala in both rodents and humans.
All the evidence points to the fact that stress hormones cause anxiety, which appears with depression.
The authors conclude that chronically high levels of cortisol has detrimental effects on the brain and on behavior and this relationship may help researchers to design new psychiatric drugs that treat the causes of disease rather than the symptoms.
The research can be seen in an issue of Behavioral Neuroscience, published by the American Psychological Association.
No matter the cause, anxiety can become a vicious circle in which the fear of anxiety itself causes an anxiety attack.