One of the biggest challenges in psychology is often the process of trying to define and understand subjects and concepts that are somewhat abstract. Perhaps the biggest example of this is personality. Personality is a very broad and vague term and so far psychology has failed to provide a single personality theory that is universally accepted or that is considered adequate for describing all the various different types of personalities and all of their myriad subtypes. Intelligence is another concept that is resistant to definition or models.
The same can also be said of stress. There are several different theories and descriptions for psychological stress but none of them are quite suitable for describing the full range of experiences that fall under the heading of this term.
When looking at models of stress, one differentiation must be made between external source of stress and our stress response. The term stress is actually used in mechanical engineering where it is used to describe the force that might be applied to certain components. Mechanical stress is what can eventually cause a fault or malfunction and the same type of physical stress can also affect human biology.
Most psychological models of stress instead deal with psychological stress and the stress response which occurs in response to 'stressors'. A 'stressor' is anything that triggers the stress response and can include anything from a predator appearing in your path, to the knowledge that your bank balance isn't quite what you'd like it to be.
A stressor can be defined then as something that causes a stress response, whereas the stress response can be defined as our reaction to a stressor – quite a roundabout definition if ever there was one!
One attempt at a model of stress comes from Holmes and Rahe who created a list of 'stressful life events' which include such items as 'the death of a spouse' or 'Christmas'. The list was useful in its day but is generally considered outdated and largely arbitrary by today's standards. Any list of stressors is always going to be subjective and vary from person to person. What you find stressful might not necessarily be what I find stressful and some people are capable of getting very worked up about things that the rest of us would never understand!
Cognitive behavioral therapy attempts to deal with stress by teaching patients to change the way they think about stressful life events. This teaches us that it's not the stressor itself that causes stress but our individual beliefs regarding that stressor.
There are also any number of stress questionnaires that attempt to measure psychological stress in humans, but like other models of stress they tend to be flawed – though potentially useful for some therapeutic applications. Measuring your stress on a scale of one to ten is very much like measuring your pain on a scale of one to ten (which is a diagnostic method used by doctors) – it lacks a point of reference and is entirely subjective.
When discussing models of stress it's also useful to consider the different types of stress.
One of the biggest issues with regards to types of stress is the difference between acute stress and chronic stress. Acute stress describes the immediate 'fight or flight response' which occurs in response to an immediate danger. This is the feeling we get when we are presented with a danger such as a predator, a house fire or an aggressor with a weapon. It's also the same response that is more likely these days to be triggered by public speaking, an argument with a cashier or watching a stressful thriller on TV.
The fight or flight response is one of the best models of stress we have and describes stress in terms of the biochemical reaction it causes in the body – characterized by the release of adrenaline, norepinephrine, dopamine and cortisol among other things. This then causes a number of physiological changes in the body, including the increase in blood pressure, the increased heart rate, muscle contractions and increased focus. In the short term, this is an adaptive response that makes us more physically and mentally capable of surviving any kind of situation.
Chronic stress is what happens when the stressor doesn't 'go away' which is the case often with something like debt. You can't 'outrun' debt, no matter how hard you might try! Because chronic stress redirects blood and oxygen away from the digestive system and immune system and towards the muscles, this then leaves the body vulnerable to various health complications if stress continues for an extended period. Continuous adrenaline production meanwhile can lead to adrenal fatigue. And thus you have the modern dilemma of a 'constantly stressed' mankind.
But models of stress also need to take into account the nuanced nature of this dichotomy. For starters, 'acute' and 'chronic' are not really binary terms. What would you use to describe the stress you feel in the week leading up to giving a speech for instance? That's longer than acute but not quite chronic.
Some models of stress do take into account another distinguishing factor between different types of stress and that is the idea of 'eustress'. Eustress is the type of stress that can be most easily described as good stress. In other words, stress when you're being chased by a lion is useful and thus is eustress. Likewise, a little bit of chronic stress leading up to an exam could be seen as a good thing because it encourages you to revise and is a motivating factor. Without any stress at all, many of us would fail to prepare for important events or to avoid dangerous situations.
But then too much chronic stress leading up to an exam is also a bad thing. Stress negatively impacts on memory and prevents us from sleeping – sleep being very important for exams. This is where models of stress fall down again as they don't capture the shades of grey that exist between different types of stress.
Right now you are probably stressed about various things. Maybe you have a deadline at work, or maybe you had an argument with your other half this morning. But are you chronically stressed?
Likewise, the way you feel just before giving a speech and the way you feel while you're on a snowboard are both described as acute stress despite being entirely different sensations. Some people describe the sensation you get from extreme sports as being a 'flow state'. But at what point does acute stress become a flow state?
Models of stress as they exist currently fall badly short of the mark when it comes to describing the multifaceted nature of stress. Stress it seems remains resistant to definition or categorization. When you talk about stress everyone knows what you mean but at the moment it escapes a concrete definition and possibly your idea of stress is very different form someone else's! Every case of stress is slightly different and has a slightly different neurochemical profile and it's useful to keep this in mind when discussing it.