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.
There is a long list of signs and symptoms of an anxiety attack. But because each body is somewhat chemically unique, anxiety attacks can affect each person differently. Consequently, anxiety attack symptoms can vary from person to person in type or kind, number, intensity, duration, and frequency. If your symptoms don’t exactly match this list, that doesn’t mean you don’t have anxiety attacks. It simply means that your body is responding to them slightly differently.
Women are more than two times as likely as men to be diagnosed with an anxiety disorder. (6) It’s not clear why this is the case, but researchers have theorized that it may be due to a combination of social and biological factors. Scientists are still investigating the complex role that sex plays in brain chemistry, but some research suggests that in women, the amygdala, which is the part of the brain responsible for processing potential threats, may be more sensitive to negative stimuli and may hold on to the memory of it longer. (7) 
Separation anxiety disorder: Separation anxiety is often thought of as something that only children deal with; however, adults can also be diagnosed with separation anxiety disorder. People who have separation anxiety disorder have fears about being parted from people to whom they are attached. They often worry that some sort of harm or something untoward will happen to their attachment figures while they are separated. This fear leads them to avoid being separated from their attachment figures and to avoid being alone. People with separation anxiety may have nightmares about being separated from attachment figures or experience physical symptoms when separation occurs or is anticipated.
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