There are many different panic attack causes, and it’s impossible to tell which one causes panic disorder. As a matter of fact, more and more research shows that the panic attack causes can be found in genetic and environmental factors, such as possessing certain genes and/or experiencing traumatic events. This page discusses scientific evidence that explains why both environmental and genetic factors partially contribute to the development of panic disorder. Please note, however, that having family members with an anxiety disorder, or having experienced childhood traumatic events, does not mean that a person will develop panic disorder; they are panic attack causes, but it only increases the chance for someone to develop panic disorder.
There are a lot of scientific articles linking certain genes to the increased chance of developing panic disorder. The heritability of panic disorder is moderate (ranging from 31 to 88%) . An overview:
Study  found shared genetic determinants to be the major underlying cause of the developmental continuity of childhood separation anxiety disorder into adult panic disorder . One such determinant could be the monoamine oxidase A allele. Among German and Italian females with panic disorder (participated in study ), researchers found significantly longer alleles (3a, 4, and 5), compared to German and Italian females without panic disorder. Reduced monoamine oxidase A activity is associated with impulsiveness and aggressiveness in humans, but it is unclear to which panic disorder symptom (panic attacks, anticipatory anxiety or phobic avoidance) monoamine oxidase A contributes . Another such factor could be the personality trait neuroticism ; researchers founds the genes responsible for neuroticism to be present in people with internalizing disorders, such as panic disorder. People who score high on neuroticism are more sensitive to symptoms of stress, anxiety, and panic.
In study , researchers found a moderate total heritability of 41 to 44%. This is in line with findings from other studies where researchers found that when one twin has panic attacks, the other twin has a bigger chance (ranging from 31-88%) of having an anxiety disorder . Another study demonstrated that more than 90% of the probands and first-degree relatives with panic disorder also had an affective disorder diagnosis, such as bipolar disorder . (Probands are the first in the family tree to develop a certain mental disorder). Also, another study found a link between panic disorder and the ADORA2A gene , which has been reported in several studies.
There is a high genetic corrolation between generalized anxiety disorder (GAD) and panic disorder: 0.83, which suggests a common etiology between panic disorder and GAD . The connection between GAD and panic disorder is further supported by study  where researchers found GAD symptoms to be responsible for 37.9% for panic disorder symptoms and PTSD symptoms. The panic disorder symptoms were responsible for 20.7% for the GAD symptoms and PTSD symptoms .
People with panic disorder display a strong conditioned fear generalization compared to people without panic disorder. According to study , panic people react stronger to less threatening information compared to healthy people. This overgeneralization could lead to encounter more panic reminders in the days/weeks/months following a panic attack.
Environmental factors partially explain the development of panic disorder and its symptoms. Also, traumatic experiences seem to be a predictor of the onset of panic disorder .
Researchers found that life experiences with other relatives or alone increase the risk of developing panic disorder . A modest relationship between shared environmental risk factors and neuroticism and internalizing disorders  was found in a twin study, which suggests that experiencing the same events increases the development of internalizing disorders (such as panic disorder), but not as much as genes do. NOTE: by life experiences they mean those that negatively affect someone’s life.
Significantly more people with panic disorder, compared to people without a psychiatric disorder, report traumatic childhood experiences (68.7% versus 37.1%), reported the attitude of their parents as more restrictive, and providing less love, care, and attention . Also, there were more psychiatric disorders present in the families of those with panic disorder . A connection between PTSD and panic disorder has also been found in study ; 21.3% of the PTSD symptoms could explain panic disorder symptoms, and  where 24.1% of women and 5% of men with panic disorder reported a history of being sexually molested.
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