Because stress can affect the mental health of individuals, it can also bring forth several behavioural problems. According to several studies, the common behavioural effects of chronic stress include diminished sociability and reduced confidence. Thus, people subjected under too much stress for a prolonged period often exhibit antisocial and risk aversion tendencies.
Researchers Carmen Sandi et al have discovered that chronic stress triggers an enzyme called MMP-9 to attack the synaptic regulatory molecule nectin-3 in the hippocampus region resulting in loss of adherence between neurons or synaptic plasticity. Subsequently, because this transpires in the hippocampus, the outward manifestations of nectin-3 downregulation include loss of sociability and peer avoidance.
It is also worth mentioning that stress increases the predisposition of brain toward mental disorders. The study of Stephen S. G. Ferguson et al has determined the biological link between stress, anxiety, and depression. Accordingly, chronic stress activates a protein known as corticotropin releasing factor receptor 1 or CRFR1 that in turn, triggers anxiety and promotes the release of specific types of serotonin receptors called 5-HTRs on cell surfaces in the brain. An abundance of 5-HTRs result in abnormal brain signalling and thus, depression.
People suffering from anxiety or depression also display behavioural problems. Both mental disorders could promote abhorrence to social interactions. For example, individuals with anxiety disorders have an overwhelming level of worry and fear that are crippling. On the other hand, those who are suffering from clinical depression exhibit persistent low mood and low self-esteem accompanied by loss of interest or pleasure in normally enjoyable activities.
But apart from diminished sociability due to antisocial tendencies, stress could also reduce confidence and promote risk aversion. Another study from Carmen Sandi et al revealed that people who have higher predisposition toward anxiety are more likely to be less confident and less competitive when under stress—as opposed to low-anxiety people who exhibit overconfidence and become highly competitive when subjected under stress.
Sandi et al concluded that stress is a considerable factor for fostering inequality among people because of the role it plays in building or reducing confidence. Note that confidence is essential to the ability of each individuals to compete in the society and those who are less confident are less likely to make the kind of decisions that can give them a social and financial edge over others. The researchers noted that confidence is central in the organisation and function of human societies because it drives social competition.
A study by John Coates et al investigated the link between stress level and risk aversion. They recruited volunteers and administered them with hydrocortisone—the pharmaceutical form of the stress hormone cortisol—over an eight-day period to effectively raise their stress level while they participated in a lottery-style financial risk-taking task with real monetary payoffs.
The result of the experiment revealed that an initial spike of cortisol had little effect on behaviour but a chronically high and sustained levels led to a dramatic drop in the willingness of the volunteers to take risks. Take note that this experiment emulated real-world situation in which financial traders are subjected under sustained high levels of stress during market slumps caused by financial or economic crises. The researchers mentioned that although stress and the release of cortisol normally has beneficial function by preparing the body for possible action by releasing glucose and free fatty acids into the blood, abnormally high level of this hormone due to chronic stress could impaired cognitive abilities, heightened anxiety, and trigger depression.
Based from the results of their study, Coates et al hypothesised that the stress-induced shifts in risk preferences might be a cause of market instability that has been hitherto overlooked by economists, risk managers, and central bankers—especially considering that several established and influential economic, financial, and biological models assume that risk preference are a stable trait.
Cognition psychologists Lars Schwabe and Oliver Wolf have also linked stress with conflict between habits and goal-directed behaviours. Their study revealed that the interaction of the stress hormones hydrocortisone and noradrenaline shuts down the activity of brain regions for goal-directed behaviour—particularly the orbitofrontal and medial prefrontal cortex—while leaving the brain regions for habitual behaviour.
Thus, while under chronic stress, an individual has the tendency to lose sight of his or her goals while also lapsing back into habits. In other words, individuals who are under too much stress do not behave based on their predetermined goals but according to habit.
Results of the referenced studies revealed that the behavioural effects of chronic stress revolve around antisocial tendencies and risk-free and insecure decision-making. However, a more profound takeaway from these results centre on the macro-level impact of stress.
The separate studies of Sandi et al and Coates et al suggest that collective stress has far reaching implications that could influence the course of an entire group or community. This is inevitable nonetheless. Stress brings forth behavioural problems and when it is pervasive in a group and community, the collective behaviours could affect social interactions and organisations.
More details of the study of Sandi et al are in the article “Role for MMP-9 in stress-induced downregulation of nectin-3 in hippocampal CA1 and associated behavioural alterations” published in 2014 in the journal Nature Communications. More details of the study of Ferguson et al are in the article “The psychobiology of depression and resilience to stress: Implications for prevention and treatment” published in 2005 in the journal Clinical Psychology.
Further details of the study of Sandi et al are in the article “Stress pulls us apart: Anxiety leads to differences in competitive confidence under stress” published in 2015 in the journal Psychoneuroendocrinology. Details of the study of Coates et al are in the article “Cortisol shifts financial risk preferences” published in 2013 in the journal Proceedings of the National Academy of Sciences of the United States of America.
More details of the study of Schwabe and Wolf are in the article “Simultaneous glucocorticoid and noradrenergic activity disrupts the neural basis of goal-directed action in the human brain” published in 2012 in The Journal of Neuroscience.