Most people will experience the intense fear of a panic attack at some point in their lives. However, not all people who will experience a panic attack will progress to develop Panic Disorder. People who will eventually be diagnosed with Panic Disorder are characterized by a dispositional emotive sensitivity to somatic sensations that are related to and closely connected with anxiety. The most common somatic sensations that accompany the experience of anxiety originate from changes in the temperature of the body, the breathing rhythm, the bowel movements and the cardiac rhythm. Most of the time, people who experience anxiety are not attentive to these somatic sensations. They take place below the level of conscious awareness. Until the first time that the conscious mind will direct its attention to some of these sensations, particularly the cardiac rhythm. At that point, life will change significantly for those with a dispositional emotional indifference and those with a dispositional emotional sensitivity to the bodily sensations of anxiety.
Persons with a dispositional emotional indifference to the bodily sensations of anxiety will interpret their body functioning as normal and expected. They will feel safe in themselves, in spite of the surprising realization that their body seems to be doing something new. They will not try to explore further why they felt as they felt, because they instinctively trust their body. Those with a dispositional emotional sensitivity to the somatic changes that accompany an anxious experience will automatically direct their thinking processes to the newly discovered bodily sensations. And they will try to understand why their body reacts in this new way. What they usually find is a catastrophic medical explanation.
Most people know very little about the psychology of anxiety and fear. For instance, they do not know that fear is the most valuable protective mechanism of the human organism. And they do not know that the emotion of fear is always accompanied by changes in the functioning of the body. And the changes in the functioning of the body are accompanied by somatic sensations that are a normal and safe experiential complement of these biochemical changes. They lack this fundamental psychological knowledge. Therefore, at the incidence of the first panic attack, they will incorrectly think that this is the first time their body reacts in this way and they will interpret their body functioning as a somatic alarm for an approaching medical catastrophe (most often a developing heart attack). From that point on, their mind automatically and repetitively enters into an anticipatory mode for detecting such somatic sensations, in order to take precautionary action and protect their lives. The transition from the experience of a panic attack to the development of Panic Disorder is mediated by the Panic anticipatory mechanism.