The Stress Cycle

The Stress Cycle

By Jimmy Petruzzi

The ability to react instinctively and expediently to threatening situations is thought to be linked to the evolutionary development of humans, not only by triggering reactions in the sympathetic nervous system, but our cognitive processes as well, with the objective to activate appropriate behaviour. In the process muscles are primed, attention focused, nerves are stimulated, and thoughts and feelings generated to motivate action. The stress process is very important in a variety of psychological fields of study, as it greatly impacts on psychological well-being and behaviour. Stress-related conditions are believed to be the primary factor at the root of all psychological problems and dysfunctions. The physiological stress reaction is explained as follows [1]:

 When stress occurs, the sympathetic nervous system is triggered. Norepinephrine is released by nerves, and epinephrine is secreted by the adrenal glands. By activating receptors in blood vessels and other structures, these substances ready the heart and working muscles for action. Acetylcholine is released in the parasympathetic nervous system, producing calming effects. The digestive tract is stimulated to digest a meal, the heart rate slows, and the pupils of the eyes become smaller. The neuroendocrine system also maintains the body’s normal internal functioning. Corticotrophin-releasing hormone (CRH), a peptide formed by chains of amino acids, is released from the hypothalamus, a collection of cells at the base of the brain that acts as a control center for the neuroendocrine system. CRH travels to the pituitary gland, where it triggers the release of adrenocorticotropic hormone (ACTH). ACTH travels in the blood to the adrenal glands, where it stimulates the release of cortisol.

It is when psychological stress is severe or prolonged that reactions become harmful and persistent, such as deteriorating memory, decreased immune function, reduced muscular activity, chronic hypertension, obesity, and premature ageing. In addition, a person’s sense of control is negatively affected, and a perception of helplessness is generated. People become chronically hostile, irritable, impulsive, and dissociated.

Therefore, stress has an important and pronounced impact on the physiological and psychological state, and behaviour of a person. Where “positive” stress, also called eustress (e.g. moderate, sporadic, and small amounts), may be desired and beneficial in improving performance, motivation, and adaptation, excessive amounts of stress, or distress, can cause persistent damage, including disease, anxiety, depression, and dysfunctional behaviour, including addiction and violence. Although genetic inheritance undoubtedly plays a role in determining individual differences in response to adverse events, poor childhood care is an important factor that can set in motion undesirable psychological sequelae dysregulation of affect, provocative behaviours, the avoidance of intimacy, and disturbances in attachment, of which the effects will resonate physiologically and psychologically into adulthood [2].

From the descriptions above, it is clear that the entire body and its chemical and biological systems are affected by experiences of trauma and, not only are the results directly limited to when actual events occur, but there are residual, chronic effects that cause a long-term, lasting change in the functioning of those affected. The neurobiology of trauma is made up by neural networks and physical structures in the brain.

This article is for educational purposes only

References

[1]     Carey, J. (2005). Brain facts: A primer on the brain and nervous system. Washington, DC: Society for Neuroscience.

[2]      Schneiderman, N., Ironson, G., & Siegel, S. D. (2005). Stress and health: Psychological, behavioral, and biological determinants. Annual Review of Clinical Psychology, 1, 607-628. DOI: 10.1146/annurev.clinpsy.1.102803.144141