Genetics and family history (e.g., parental anxiety) may predispose an individual for an increased risk of an anxiety disorder, but generally external stimuli will trigger its onset or exacerbation. Genetic differences account for about 43% of variance in panic disorder and 28% in generalized anxiety disorder. Although single genes are neither necessary nor sufficient for anxiety by themselves, several gene polymorphisms have been found to correlate with anxiety: PLXNA2, SERT, CRH, COMT and BDNF. Several of these genes influence neurotransmitters (such as serotonin and norepinephrine) and hormones (such as cortisol) which are implicated in anxiety. The epigenetic signature of at least one of these genes BDNF has also been associated with anxiety and specific patterns of neural activity.
The review, conducted by researchers at Cambridge University in England, also found that people with chronic health conditions were more likely to experience anxiety. According to the review, almost 11 percent of people with heart disease in Western countries reported having generalized anxiety disorder (GAD). In addition, 32 percent of those with multiple sclerosis had some kind of anxiety disorder. (3)
There is evidence for panic disorder-like diagnoses across cultures, such as ataque de nervios in Latin American communities. Research has shown that African Americans experience more functional impairment (i.e., impact on one's ability to complete daily activities) than non-Latino white Americans. This is not an exhaustive list of cultural factors related to panic disorder, but it does highlight cultural differences that may affect the presentation of panic disorder as well as individual differences in the interpretation of panic symptoms (Asnaani, Gutner, Hinton, & Hofmann, 2009; Hofmann & Hinton, 2014; Lewis-Fernández, et al., 2010).
Psychodynamic theory posits that anxiety is often the result of opposing unconscious wishes or fears that manifest via maladaptive defense mechanisms (such as suppression, repression, anticipation, regression, somatization, passive aggression, dissociation) that develop to adapt to problems with early objects (e.g., caregivers) and empathic failures in childhood. For example, persistent parental discouragement of anger may result in repression/suppression of angry feelings which manifests as gastrointestinal distress (somatization) when provoked by another while the anger remains unconscious and outside the individual's awareness. Such conflicts can be targets for successful treatment with psychodynamic therapy. While psychodynamic therapy tends to explore the underlying roots of anxiety, cognitive behavioral therapy has also been shown to be a successful treatment for anxiety by altering irrational thoughts and unwanted behaviors.
People with panic disorder often worry about when the next attack will happen and actively try to prevent future attacks by avoiding places, situations, or behaviors they associate with panic attacks. Worry about panic attacks, and the effort spent trying to avoid attacks, cause significant problems in various areas of the person’s life, including the development of agoraphobia (see below).