Stress (medicine) Totally Explained

Everything about Stress Medicine totally explained

Stress is the consequence of the failure to adapt to change. Less simply: it's the condition that results when person-environment transactions lead the individual to perceive a discrepancy, whether real or not, between the demands of a situation and the resources of the person's biological, psychological or social systems.
In medical terms, stress is the disruption of homeostasis through physical or psychological stimuli. Stressful stimuli can be mental, physiological, anatomical or physical reactions. The term 'stress' in this context was coined by Austro-Canadian endocrinologist Hans Selye, who defined the General Adaptation Syndrome or GAS paradigm in 1936.

Models of Stress

Lazarus

Richard Lazarus published in 1974 a model dividing stress into eustress and distress. Where stress enhances function (physical or mental, such as through strength training or challenging work) it may be considered eustress. Persistent stress that isn't resolved through coping or adaptation, deemed distress, may lead to escape (anxiety) or withdrawal (depression) behavior. The difference between experiences which result in eustress or distress is determined by the disparity between an experience (real or imagined), personal expectations, and resources to cope with the stress. Alarming experiences, either real or imagined, can trigger a stress response. Therefore, Lazarus's model argues that cognitive processes of appraisal are central in determining whether a situation is potentially threatening or harmful.

Zajonc

Robert B. Zajonc (1984), somewhat in opposition to the Lazarus model of stress, argued that emotional reactions occur before cognitive reactions, and in fact, may be at odds with cognitive responses. This belief was consonant with the previous James-Lange hypothesis (1890, 1922), which held that the body's emotional reaction to stress occurred prior to and resulted in conscious responses.
The debate has underscored the existence of two modes of reactivity, one conscious and under volitional control, and the other automatic and uncontrollable. Scholars such as Aldwin have argued for a simultaneous, parallel processing approach rather than a sequential neurological processing model where emotions come first followed by cognition, or vice versa on rats and other animals by exposing them to unpleasant or harmful stimuli. He found that all animals showed a very similar series of reactions, broken into three stages. He describes this universal response to the stressors as the General Adaptation Syndrome, or GAS, in 1936.

Alarm ť This is the 1st stage. When the threat or stressor is identified or realized, the body's stress response is a state of alarm. During this stage adrenaline will be produced in order to bring about the fight-or-flight response. There is also some activation of the HPA axis, producing cortisol.

Resistance ť This is the 2nd stage. If the stressor persists, it becomes necessary to attempt some means of coping with the stress. Although the body begins to try to adapt to the strains or demands of the environment, the body can't keep this up indefinitely, so its resources are gradually depleted.

Exhaustion ť This is the 3rd stage. In the final stage in the GAS model, all the body's resources are eventually depleted and the body is unable to maintain normal function. At this point the initial autonomic nervous system symptoms may reappear (sweating, raised heart rate etc.). If stage three is extended, long term damage may result as the capacity of glands, especially the adrenal gland, and the immune system is exhausted and function is impaired resulting in decompensation. The result can manifest itself in obvious illnesses such as ulcers, depression or even cardiovascular problems, along with other mental illnesses.

Neurochemistry and Physiology

The neurochemistry of the stress response is now believed to be well understood, although much remains to be discovered about how the components of this system interact with one another, in the brain and throughout in the body.
In response to a stressor, corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP) are secreted into the hypophyseal portal system and activate neurons of the paraventricular nuclei (PVN) of the hypothalamus. The locus ceruleus and other noradrenergic cell groups of the medulla and pons, collectively known as the LC/NE system, also become active and use brain epinephrine to execute autonomic and neuroendocrine responses, serving as a global alarm system.
The autonomic nervous system provides the rapid response to stress commonly known as the fight-or-flight response, engaging the sympathetic nervous system and withdrawing the parasympathetic nervous system, thereby enacting cardiovascular, respiratory, gastrointestinal, renal, and endocrine changes.

Common factors of stress

Both negative and positive stressors can lead to stress. Some common categories and examples of stressors include:

Sensory: pain, bright light

Life events: birth and deaths, marriage, and divorce

Responsibilities: lack of money, unemployment

Work/study: exams, project deadlines, and group projects

Personal relationships: conflict, deception

Lifestyle: heavy drinking, insufficient sleep

Environmental: Lack of control over environmental circumstances, such as food, housing, health, freedom, or mobility

Social: Struggles with conspecific individuals and social defeat can be potent sources of chronic stresses

Adverse experiences during development (for example prenatal exposure to maternal stress, poor attachment histories, sexual abuse) are thought to contribute to deficits in the maturity of an individual's stress response systems. One evaluation of the different stresses in people's lives is the Holmes and Rahe stress scale.

Adaptation to stress

Responses to stress include adaptation, psychological coping such as stress management, anxiety, and depression. Over the long term, distress can lead to diminished health or illness; to avoid this, stress must be managed.

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