The first discovery of oxytocin was made in 1906 by British pharmacologist Sir Henry Hallett Dale. Since that time, the scientists from different fields have been investigating this hormone. Psychologists did not avoid a temptation to study its actions in the areas of clinical psychology (e.g., Autism, fear, anxiety, and depression), behavioural psychology (e.g., addiction vulnerability, maternal behaviour and in-group bonding), and social psychology (e.g., expressing generosity and trust, and family relationships) either.
Currently, the topic about the quality of family relationships and health within a neurochemical perspective is occupying health psychologists’ minds. In the recent special issue of the American Psychologist, Dr. Uchino and Dr. Way proposed a model that underlined the importance of deeper investigation of biological pathways between these constructs. The key focus of their model was the oxytocin system that influences the hypothalamic–pituitary–adrenal (HPA) axis, immune, and autonomic nervous systems. Through this influence, oxytocin creates a reciprocal coregulation that have physiological effects on human health.
The start point of the process is a person with his or her genetic variations, early life issue, belonging to a certain relationship type and so forth. Social interactions trigger oxytocin signaling which has an impact on neural regions for emotional processing and vice versa. These processes constitute of neurochemical pathways. At the same time, positive family/romantic relationships (i.e., stress-buffering caring and warmth) or negative family relationships (i.e., insensitivity and conflicts) also influence the coregulation between oxytocin and socio-emotional processing. Within this reciprocal coregulation, raised level of oxytocin increases behaviour that facilitates social engagement. These inter-relations create a vicious circle. This part of the model is consistent with the findings that supported the idea that both negative and positive relationships can lead to the increase in oxytocin level that in its turn could also increase social salience or affiliative motivation. Especially intriguing in this coregulation is that oxytocin level of one partner changes not only this individual’s behaviour but also the oxytocin level of the interaction partner, creating in this way a dyadic process.
The most intriguing part of the model is the suggestion that health problems could ultimately develop in a result of insufficient contacts among close people. Parental neglect of a child is a well-investigated risk factor for dysfunctional relationships of this child in the adulthood as well as poor health outcomes. This fact is explained by the link between less attuned parenting and the decrease of the oxytocin level during the period of brain development of the infant. This process is assumed to have a negative impact on the function of the infant’s oxytocin system as well as on the mechanistic pathways of the central and peripheral systems.
Oxytocin has been proven to have effects on the outcome of those diseases that are related to modifications of peripheral physiological systems – autonomic, neuroendocrine, and immune systems. The HPA axis is the system directly influenced by fluctuations in oxytocin. How does it work? Stress-induced firing of neurons in the hypothalamus initiates the HPA response and triggers the receptor for oxytocin. When oxytocin binds to this receptor, it inhibits the HPA axis activation and increases cortisol release. The increased level of cortisol induced by psychological stress has an inhibitory effect on the oxytocin system. Research on animals showed that oxytocin prevents the negative impacts of social isolation on the cortisol reaction to stress, neuroinflammation, and vagal tone.
Oxytocin has been found to decrease blood pressure in cordial close relationships. Although there is no extensive research in oxytocin influence on inflammation, few experimental studies demonstrated its connection to increased levels of proinflammatory cytokines at the presence of feelings of social disconnection. Based on the reported findings, scientists inferred that oxytocin could influence multiple health-related physiological pathways and could ideally serve as a bridge between social realm and biological systems that contribute to health.