Panic attacks, a hallmark of panic disorder, are sudden and repeated bouts of overwhelming fear. These attacks, which often begin in adolescence or early adulthood, are much more intense than normal feelings of anxiety or stress. They usually pass after a few minutes and typically last no longer than an hour, but can continue to recur throughout a day.
Unexpected Panic Attacks: These panic attacks occur suddenly without any obvious cause or indication. When an unexpected panic attack occurs, a person can be completely relaxed before symptoms develop. This type of panic attack doesn't accompany any conscious internal cues, such as having fearful thoughts, feelings of intense dread and anxiety, or uncomfortable physical sensations. Unexpected attacks also don't occur with external cues, such as specific phobias or being exposed to a frightening event or situation.
Moreover, this hypocapnia and release of adrenaline during a panic attack cause vasoconstriction resulting in slightly less blood flow to the head which causes dizziness and lightheadedness.[28][29] A panic attack can cause blood sugar to be drawn away from the brain and toward the major muscles. Neuroimaging suggests heightened activity in the amygdala, thalamus, hypothalamus, and brainstem regions including the periaqueductal gray, parabrachial nucleus, and Locus coeruleus.[30] In particular, the amygdala has been suggested to have a critical role.[31] The combination of high arousal in the amygdala and brainstem along with decreased blood flow and blood sugar in the brain can lead to dramatically decreased activity in the prefrontal cortex region of the brain.[32] There is evidence that having an anxiety disorder increases the risk of cardiovascular disease (CVD).[33] Those affected also have a reduction in heart rate variability.[33]
While a single panic attack may only last a few minutes, the effects of the experience can leave a lasting imprint. If you have panic disorder, the recurrent panic attacks take an emotional toll. The memory of the intense fear and terror that you felt during the attacks can negatively impact your self-confidence and cause serious disruption to your everyday life. Eventually, this leads to the following panic disorder symptoms:
Neural circuitry involving the amygdala (which regulates emotions like anxiety and fear, stimulating the HPA Axis and sympathetic nervous system) and hippocampus (which is implicated in emotional memory along with the amygdala) is thought to underlie anxiety.[55] People who have anxiety tend to show high activity in response to emotional stimuli in the amygdala.[56] Some writers believe that excessive anxiety can lead to an overpotentiation of the limbic system (which includes the amygdala and nucleus accumbens), giving increased future anxiety, but this does not appear to have been proven.[57][58]
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.