^ Leicht, Gregor; Mulert, Christoph; Eser, Daniela; Sämann, Philipp G.; Ertl, Matthias; Laenger, Anna; Karch, Susanne; Pogarell, Oliver; Meindl, Thomas; Czisch, Michael; Rupprecht, Rainer (2013). "Benzodiazepines Counteract Rostral Anterior Cingulate Cortex Activation Induced by Cholecystokinin-Tetrapeptide in Humans". Biological Psychiatry. 73 (4): 337–44. doi:10.1016/j.biopsych.2012.09.004. PMID 23059050.
There are several different anxiety-related disorders. Some symptoms overlap across many of these disorders, and others are more specific to a single disorder. In general, however, all anxiety-related disorders feature worry, nervousness, or fear that is ongoing, excessive, and has negative effects on a person's ability to function. It can be tricky to decide when anxiety is typical or linked to a disorder, which is why diagnoses should be made by licensed professionals, such as psychologists or psychiatrists.
Panic disorder is a diagnosis given to people who experience recurrent unexpected panic attacks— that is, the attack appears to occur from out of the blue. The term recurrent refers to the fact that the individual has had more than one unexpected panic attack. In contrast, expected panic attacks occur when there is an obvious cue or trigger, such as a specific phobia or generalized anxiety disorder. In the U.S., roughly 50% of people with panic disorder experience both unexpected and expected panic attacks.
Anxiety can be either a short-term "state" or a long-term "trait". Whereas trait anxiety represents worrying about future events, anxiety disorders are a group of mental disorders characterized by feelings of anxiety and fear. Anxiety disorders are partly genetic, with twin studies suggesting 30-40% genetic influence on individual differences in anxiety. Environmental factors are also important. Twin studies show that individual-specific environments have a large influence on anxiety, whereas shared environmental influences (environments that affect twins in the same way) operate during childhood but decline through adolescence. Specific measured ‘environments’ that have been associated with anxiety include child abuse, family history of mental health disorders, and poverty. Anxiety is also associated with drug use, including alcohol, caffeine, and benzodiazepines (which are often prescribed to treat anxiety).
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)
Some research suggests that your body's natural fight-or-flight response to danger is involved in panic attacks. For example, if a grizzly bear came after you, your body would react instinctively. Your heart rate and breathing would speed up as your body prepared for a life-threatening situation. Many of the same reactions occur in a panic attack. But it's unknown why a panic attack occurs when there's no obvious danger present.
During the day if she was out, the attack felt “like my head suddenly weighed a thousand pounds and my chest would get really heavy. It literally felt like something was pulling me down. I would usually have to head home immediately. I would then experience foggy vision where it …actually looked like there was fog in the air. I also experienced double vision and parts of my body—like my neck or one arm or one entire side of my face– would go totally numb.”
If you are greatly afraid, however, such as being terrified that there is a burglar in your home that is about to harm you, the body produces a high degree stress response. We generally experience high degree stress responses as being anxiety attacks: where the changes are so profound they get our full attention. The greater the degree of anxiety and stress response, the more changes the body experiences.