Biology 202
1998 First Web Reports
On Serendip


Bonnie Kimmel

Anxiety is one of the most fundamental emotions shared by all species of animals. When confronted with danger, the fight or flight response of the sympathetic nervous system is triggered so that we are prepared to react and protect ourselves. Without anxiety and its physiological manifestations, such as hypersensitivity to environment and enhanced blood supply to leg muscles, the likelihood of harm or disaster in threatening situations would undoubtedly dramatically increase. A moderate amount of anxiety also has the result of prompting individuals to prepare for certain events, such as exams and presentations, that clearly benefit from this action.

Panic disorder is a type of anxiety disorder characterized by "brief episodes of intense fear accompanied by multiple physical symptoms (such as heart palpitations and dizziness) that occur repeatedly and unexpectedly in the absence of any external threat." Unlike fear, there is seemingly no reason or input that causes such an episode. It feels almost like an internal earthquake, something over which you have no warning and feel no control, an event that destabilizes the foundation of what you consider within the borders of normal expectation. After an initial panic attack, individuals often become incredibly fearful about the possibility of another attack. The degree to which this affects subsequent behavior and lifestyle can be extremely drastic and potentially debilitating. Whether it is a daily transformation or a more anxious reaction to the next time one feels dizzy, panic attacks have a lasting impact on the thoughts and actions of the individuals who experience them.

There are a variety of explanations for the cause of panic disorder which increasingly define it as a physiological condition, rather than a purely psychological one as was previously believed. Several theories exist that attempt to discuss the causes of panic disorder in terms of biochemical imbalances. One proposed explanation links levels of the monoamine neurotransmitters in the central nervous system (dopamine, norepinephrine, and serotonin) to the neurology of anxiety. Individuals with panic disorder may produce insufficient amounts of serotonin that “results in a high level of anxious behavior, (and) a low level of norepinephrine (that) results in a hyperactive alarm system and sensitization to novel stimuli. Similarly, gamma amino butyric acid (GABA) is another neurotransmitter that may play a role in panic disorder. GABA is present in 80% of the nerve cell connections in the brain, and "works by limiting the nerve cell activity in areas of the brain associated with anxiety." Researchers also support the notion of a genetic component to evidence for a biologically based mechanism for panic disorder. "Studies show anxiety disorders in general are five times as common in identical twins as nonidentical twins," demonstrating the likelihood of a hereditary predisposition towards the condition. These and other theories contribute towards a growing conception of panic disorder as a mental illness with a neurobiological basis.

It is also widely believed that it appears that what people with panic attacks are frightened of (i.e. what causes the panic) are the actual physical sensations of the fight/flight response. Thus, panic attacks can be seen as a set of unexpected physical symptoms and then a response of panic or fear of the symptom. Because these physical symptoms occur without any apparent cause (i.e. imminent threat of danger), we can consider this within our model of the nervous system as an output with no input. There are, however, a variety of possible explanations for why the fight or flight response may be triggered. General stress in ones life often results in increased levels of adrenaline in the body, which may periodically result in these physical symptoms (i.e. elevated heart rate), and which may remain in the body even after the stress is gone. It has also been proposed that panic attack sufferers are actually experiencing normal body changes, but are simply more keenly tuned into the state of their bodies because of previous attacks. Not understanding the root of a physical disturbance may cause individuals to fear that a larger medical condition remains undetected, and it is even possible that the anticipatory anxiety is enough to bring on another panic reaction. Within this context, panic disorder supports the notion that the organization of the nervous system yields bidirectional causation, whereby output affects input and input affects output. The extent to which this happens varies. An output, say a perceived inability to take care of a child or drive a car during an attack, will often dramatically affect how an individual acts upon subsequent experience with the same input. The effect could be as extreme as the development of a phobia of a particular input. Or, anticipatory anxiety resulting from an output behavior could be so strong that another episode is triggered due to a symptom, such as increased heart rate or dizziness, that results from a totally unrelated input.

It seems useful to apply the template that behavior is not caused, but rather is allowed to happen, to discussions about panic disorder. As with most other behaviors, panic attacks incorporate a complex and interrelated web of biological and environmental triggers. Even if we knew the exact correlation between every permutation of brain chemicals and behavior we could not predict how different individuals would act in the same situation or when faced with the same stress. From an anthropological and public health perspective, I am fascinated by how contextualizing mental illness as a neurobiological disorder that is “allowed to happen” might revolutionize societal views of mental illness. We seem to still be a society at least partially obsessed with the notion that scientific knowledge yields empirical expertise and validity. Taking the responsibility away from the individual and placing it, to some degree, in their genes and neuroanatomy, would surely affect a broad range of societal issues, including diminishing the stigma attached to a variety of illnesses. This, in turn, could affect issues such as funding for research, health care coverage, and might potentially prompt more people to seek treatment. It can be considered a segment of the path of our ever developing understanding of who we are and why things happen.

WWW Sources

NIMH Publication.

Kathryn J. Hormann. What is Anxiety?

Stephen Cox. Dr. Steve's Guidelines for Discontinuing Xanax.

Cathleen Henning. Medication for Panic Disorder.

Pauline Anderson. Drug May Help in Rx, Education of Panic Disorder, The Medical Post, January 29, 1996.

Ron Rapee, Michelle Craske, and David Barlow. The Causes of Anxiety and Panic Attacks.

Panic Attacks and Panic Disorder, The Harvard Mental Health Letter, April (Part I), May 1996, (Part II).

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