Théories du Stress et Réaction

Definition of Stress

• Stress is defined physically as a force on a solid body, caused by an external body or load
• There are three perspectives on stress: reaction, source, and the relationship between the two
• Ancient Greeks understood the link between stress and health, recognizing how stress can affect health and illness, and the various coping methods.

Stress Theories

• Stress is the reaction of an individual to events or specific stimuli
• Reaction-oriented theories (like Cannon and Seyle's theories) also view stress as a source of stimuli
• Stress as a source of stress (events): focuses on specific events that cause stress
• Stimulus-oriented theories (Holmes & Rahe) define stress as a relationship between the stimuli and the individual's reaction

Reaction-Oriented and Psychophysiological Stress Theories

• Stress is viewed as a physical reaction pattern to stressful events
• Two endogenous regulatory systems release hormones and transmitters when activated: sympathetic adrenomedullary system and hypothalamic-pituitary-adrenocortical system.

Cannon's "fight or flight" response

• This theory states that the organism reacts to increased activity from the adrenal medulla, causing the release of epinephrine (adrenaline) and norepinephrine (noradrenaline).
• This release prepares the body for the fight or flight response, increasing cardiovascular capability
• The theory of homeostasis is also important. If there's a big difference from a target value, the body will try to restore balance (e.g., fever, glucose levels).

Seyle's General Adaptation Syndrome (GAS)

• Stress is an unspecific reaction of the organism to various stressors
• Seyle observed that patients with various illnesses showed similar symptoms.
• Rat research showed similar reactions to various stimuli (e.g., heat, physical exertion, deprivation)
• Seyle's work is foundational to the study of stress

Critique of Seyle's theory

• Stressors for laboratory animals (like rats) were not diverse enough.
• Insufficient control over environmental elements that could contribute to the stress response
• Unspecific stress response in humans is questioned - Individual reactions to various stressors are likely specific and not universally the same

Stimulus-Oriented Stress Theories

• These theories emphasize life events and experiences as sources of stress.
• Focus is less on individual reaction, more on the external stimuli
• Life events can have a major impact on health
• Types stress sources include: physical (heat, noise), social (friend problems, conflicts), economic (financial troubles), ecological (pollution), occupational (time pressure, monotony)

Forms of Stress

• Stress is categorized concerning intensity, duration, and impact (macro-stress vs micro-stress; acute vs chronic): Examples may include major life events, chronic issues, or workplace pressure
• Individual experiences of stress may vary

Life Events Theory (Holmes & Rahe)

• Life events put stress on individuals by causing adjustment needs. This can lead to illness in some cases
• Examples of impactful events: the death of a loved one or marriage.
• The theory is helpful in understanding the link between impactful life events versus other events or perceptions that can cause stress

Social Readjustment Scale

• Ranks 43 stressful life events that contribute to illness
• Daily hassles are as important as major events

Critique of Stimulus-Oriented Theories

• Doesn't account for differing stress responses among individuals, and may underestimate personal perception and cognitive appraisal of stressful or impactful events
• These theories often rely on retrospective studies, which may be less accurate
• Individuals are often treated as passive victims in relation to stressors.

Transactional Model of Stress (Lazarus)

• Focus on the interaction between the individual and the environment. Stress is a relationship between the individual and their evaluation of their environment
• Primary appraisal: assessing the situation and importance (demands and resources)
• Secondary appraisal: assessing resources to deal with the demands.

Dynamic Model of Stress

• Stress is an interaction between the person and the environment.
• Whether we perceive something as stressful depends on our evaluation of the situation, resources, and demands.
• Interactions between demands and resources.

Stress and Emotions

• Perceived demands exceeding resources can lead to stress
• Stress may elicit various emotions (fear, anger, sadness), different people may face the same situation differently leading to different reactions.

Critique of the Transactional Model

• Primarily based on individual feelings and perceptions.
• The theory is difficult to measure and operationalize.

Mind-Body Interaction

• Psychological factors directly impact bodily processes and the stress response.
• Bodily stress systems are complex and work to maintain balance in the organism
• Systems like the Neuroendocrine system (including HPA axis and sympathetic adrenomedullary system) and immune system are vital

Psychobiological Stress Systems

• The HPA axis, responsible for responses to stress, with hormones like cortisol playing a role
• The ANS (autonomic nervous system) is a network of nerves impacting physiological responses
• The immune system plays a role in reacting to stress

Cortisol: The End Product of the HPA Axis

• Cortisol is a key marker of stress, measured in various bodily fluids.
• Influences body metabolism, the immune system, and brain function
• Cortisol release is tightly regulated via negative feedback loops to avoid overreaction to stress
• Deficient feedback responses to stress may be correlated to some diseases

Allostasis and Allostatic Load

• Allostasis is the ability to achieve stability through change
• Allostatic load is "wear and tear" resulting from chronic over/under-reactivity of the stress response systems
• Acute stress can be beneficial, but prolonged stress is damaging
• Chronic stress may cause dysfunction in various bodily systems

Classical Conditioning

• Explains how the immune system can be conditioned by external stimuli, impacting responses to stress.
• Conditioning can modify immune responses
• The immune system can be conditioned by classical conditioning impacting the responses to different types of stressors.

Ce quiz couvre la définition du stress, les théories réactionnelles et psychophysiologiques. Apprenez comment le stress est perçu tant comme une réaction qu'une source d'événements. Explorez l'impact du stress sur la santé et les diverses méthodes de coping à travers les âges.