Musings on Oxytocin in Things We Do and Those We Care about

Abstract

Through this introspective article, we invite the reader to look at human engagement and participation while considering the role of oxytocin in human occupations and cooccupations. We searched scholarly and popular databases to explore beyond the popular (and erroneous) acclaim of oxytocin as the “love hormone,” due to its association with good feelings and positive emotions. Produced mainly in the hypothalamus, oxytocin finds its way into the bloodstream through the pituitary gland or to the central nervous system to bind with its receptors and influence human behavior and physiology. Our exploration revealed occupationrelevant information on sexual behavior, maternal and bonding, autism, affective and other disorders, stress and emotions, and lastly, human and dog connectedness.

Keywords: oxytocin, occupational science, occupation, co-occupation, bonding, occupational engagement and participation

Introduction

Have you ever wondered how humans connect with each other in relationships that occur on a daily basis? And in the same token, why are we so connected to our pets, especially cats and dogs? What neurobiological mechanisms mediate the human ability to express love, trust and empathy? 

 We invite you to muse over the hormone/ nonapeptide called oxytocin and the human propensity for engagement and participation in individual occupations or in co-occupations, or those that we perform with others. Going beyond the information that began simply as interest in the difference in responses by breastfeeding and bottle-feeding mothers to stressful physical and emotional situations (DeAngelis, 2008), we searched popular and scholarly sources for enlightenment. Our journey exposed themes of occupation-rich information on sexual behavior, maternal and infant bonding, autism, affective and other disorders, stress and emotions, and lastly, connectedness between humans and dogs. We hope that the information we share can be applied to your own occupations and in your occupational therapy practice

Neurobiology of Oxytocin

Oxytocin is a neuropeptide that plays a major role in the preservation of species, i.e., reproduction across vertebrates, influencing human and animal physiological, sexual and bonding behaviors. It originates primarily from the paraventicular and supraoptic nuclei of the hypothalamus, and the posterior pituitary releases oxytocin into the bloodstream as a response to breastfeeding, childbirth, and certain physical and emotional stress. Oxytocin projects widely to the central nervous system and peripheral tissues involved in the reproductive system and the heart of both males and females, thereby influencing sexual excitation, parturition, lactation, and responses from the kidney, heart, thymus, pancreas, and adipocytes (Gimpl & Fahrenholz, 2001).

Oxytocin is part of the positive feedback loop that occurs during neurodevelopment in utero and continues after birth impacting the bonding of the parent and infant. The importance of this relationship between infant and mother can be enhanced by providing the proper maternal care environment thus improving development and regulation of the infant’s states (Weber, Harrison, Steward, 2018). Foster mothers who take delight in their foster infants demonstrate similar amounts of oxytocin in their brain activity and caregiving as biologically related mothers suggesting the important role oxytocin has in bond formation (Bick, Dozier, Bernard, Grasso & Simons, 2013). Feldman, (2001) reported that maternal oxytocin levels in the first trimester can predict the amount of postpartum behavior and its coordination with infant state. This synchrony of physiological states of parent and infant helps to develop affiliative bonds, promote care and development, and ameliorate anxiety for both. The maternal-fetal relationship is influenced by the mother’s psychological state and her physiology including the endocrine and neuropeptide mediated by the hormonal levels. Women who displayed a pattern of increasing oxytocin from the first trimester throughout the first month post-partum reported higher levels of maternal-fetal attachment in pregnancy (DiPietro, 2010). Oxytocin studies have also looked at the effect of oxytocin when introduced as neonates on parenting and pair-bonding in voles or field mice. Bales et al, (2007) reported that administration of oxytocin to female neonate prairie voles showed a difference as adults in terms of their alloparental and partner preferences. The adults who received a lower dose of oxytocin (2 mg/kg) as neonates took longer to approach and care for vole pups and showed a statistically significant preference for a partner. Those with medium dose of oxytocin (4mg/kg) recovered their pups more frequently but no longer showed preference for partners. The vole mothers who received the highest oxytocin dose (8 mg/kg) showed more time with side-to-side contact with a male mouse than any of the other dosage groups.

Oxytocin and the Mother-Infant Bond

The relationship between a mother and her infant is a complex network of balance between the biology and the psychology between these interactions. This dynamic interaction is vital to infant development as well as a woman’s transition into motherhood (Galbally, Lewis, Ijzendoorn & Permezel, 2011). While human studies are in the beginning phases, oxytocin, appears to have a large role in this process. Studies involving animals have studied the role of oxytocin in motherhood, finding a link between oxytocin, maternal behavior and bonding (Numan, Fleming, & Levy, 2006). Preliminary studies in humans have shown that oxytocin may play a role throughout delivery, lactation all the way to the mother’s regulation of mood and her ability to parent (Burbach, Young & Russell, 2006).

The most interesting and promising link found in multiple emerging studies, shows that increase in oxytocin levels throughout pregnancy leads to a more successful bond between the new mother and her infant as well as facilitates maternal behavior post-delivery. This is achieved through oxytocin’s stress and anxiety reduction properties as a less anxious mother can more readily increase her focus on her infant and its care as well as her own mental state (Uvnäs-Mobcrg, Widström, Nissen, & Björvell, 1990; Chiodera, Salvarani, BacchiModena, Spallanzani, Cigarini, Alboni, Coiro, 1991; Light, Smith, Johns, Brownley, Hofheimer, & Amico, 2000). Overall, the research suggests that elevated levels of oxytocin throughout pregnancy, delivery and post-partum assists in the transition from pregnancy to motherhood and greatly assists in the mother-infant bond during the infants first stage of life (Levine, Zagoory-Sharon, Feldman, & Weller, 2007; Feldman, Weller, ZagoorySharon, & Levine, 2007; Bick & Dozier, 2010).

Jobst et al (2016) discovered a link between oxytocin levels and postpartum depression (PPD) which is particularly helpful when looking at mothers in their new role. As previous studies have found that in most mothers, oxytocin levels begin to rise during pregnancy and continue to do so throughout and into the postpartum phase. Alternatively, Jobst et al (2016), determined that there was a difference in the changes of oxytocin levels between women experiencing a typical transition and those with PPD symptoms. In this study, the levels of oxytocin decreased significantly from late pregnancy until delivery in women with PPD whereas in the healthy group, these levels continued to increase into the postpartum period. This study brings about the question of the potential of using oxytocin levels as a predictive factor during pregnancy for postpartum depression.

Oxytocin also plays a role in the biological process of motherhood, lactation. When a mother nurses her child, oxytocin is released not only from the mother’s brain but the infant’s as well. While oxytocin plays a large role in the biological process of milk ejection, it also provides other effects to the breastfeeding mother such as; decreased anxiety and blood pressure, increased social interaction and increased gastrointestinal tract function (Uvnäs-Moberg,1996; Handlin et al, 2009; Jonas et al, 2008). Skinto-skin contact post birth with the mother and infant allows for the infant to engage in an innate rooting, breast seeking behavior (Widstom, 1987). This behavior leads to the release of oxytocin in both the mother and child, jump starting the beginnings of the mother-infant relationship. These early skin-to-skin interactions lead to increased success with breastfeeding, a calmer infant that cries less and a calmer mother with less anxiety (Bergman, Linley, & Fawcus, 2004; Bystrova et al, 2007). In turn, mothers and infants that experience this early skin-toskin contact have a sophisticated anti-stress pattern that is oxytocin linked.

Long-term effects of this postbirth oxytocin release have been found in both mothers and infants. Mothers who have breastfed their infants are at a lower risk for cardiovascular disease, exhibit lower blood pressure and a lower stress reactivity, which support the benefits of repeated oxytocin exposure and release (Lee, Kim, Jee, & Yang, 2005). Furthermore, skin-to-skin contact between mother and child, particularly within the first two hours post birth has marked long term outcomes such as a more developed mother-infant interaction and increased stress handling of the infant (Klaus et al, 1972; Bystrova et al, 2009).

Longterm, if a mother and infant have a secure attachment, the release of oxytocin becomes natural and well established. The release of oxytocin the infant and its subsequent effects, can be activated by simply by seeing, hearing or smelling its mother. If the infant is able to remain in a state of perpetual happiness, feeling calm and secure even when she is not present, the mother-infant relationship is a successful secure attachment.

Oxytocin Implications on Stress and Emotions

Oxytocin is often called the “love hormone.” It is secreted through touch, emotional, psychological, possibly spiritual and cognitive, and physical bonding. It connects us as human beings to others and to our pets. It promotes attachment. It is what makes us care for others. When human beings are connected, they are more accepting of each other. A gentle hand on a hand or shoulder is comforting as is a hug. Human touch can mediate stress, sorrow, and in some cases anger. It can double joys and spread happiness. It allows us to engage in co-occupations, heal ourselves and others, and manage our selfregulation. Touch is the primary method of eliciting oxytocin in the body. While touch can be violent and traumatizing, touch that is graded, warm, gentle and caring can elicit positive feeling and connection through the hormone oxytocin.

Intranasal oxytocin administered twice daily over 12 weeks was found to decrease negative symptoms in individuals with schizophrenia (Jarskog, Pedersen, Johnson, Hamer, Rau, Elliott & Penn, 2017). Oxytocin and vasopressin are neuropeptides that play a key role in social attachment, and affiliation, including parental care and pair-bonding, along with prosocial behavior which may provide avenues of intervention for psychiatric disorders in which these hormones interface (Stein, 2009). While sexual intimacy is cognitively and emotionally mediated, laboratory investigations of hormonal release during human sexual activity show that oxytocin is necessary for subjective pleasure during arousal and orgasm in both sexes. Further investigation is needed to determine if and how oxytocin plays a role in puberty, aggressive and protective feelings, and consistency of sexual interest in committed relationships (Hiller, 2004). Recent review of literature exploring the relationship of oxytocin’s role as a mediating agent for reward, social affiliation and bonding, stress and learning and memory demonstrated strong evidence for the use of oxytocin as possible treatment for drug addiction, opioid addiction and depression-addiction co-morbidity. Its biochemical interactions and effects on the amygdala, hypothalamic-pituitary-adrenal axis and memory consolidation of traumatic memories lends itself to further investigation as a pharmacological therapy to prevent relapse in opioid addiction and co-existing affective disorders (Zanos, Georgiou, Weber, Robinson, Kouimtsidis, Niforooshan & Baily, 2018). Additionally, a pilot study evaluating the level of oxytocin in patients with chronic depression receiving Cognitive Behavioral Analysis System of Psychotherapy (CSASP) demonstrated improvement as the level of oxytocin increased in the blood plasma of these patients. However, the authors found that those individuals who started with low oxytocin plasma levels at baseline had smaller changes in response to CSASP, indicating that oxytocin blood plasma levels may predict the outcome of psychotherapy for individuals with chronic depression (Jobst, Sabals, Hall, Bruklmeier, Buchheim, Hall, et al., 2018). While we think of oxytocin as the “love hormone” much more research needs to occur in order to determine the beneficial dosage and how genetic expression mediates the utilization of oxytocin, as with all its benefits a dark side of oxytocin exits as well. Biologically different expressions of oxytocin may contribute to suicide attempts and increased aggression under high stress life events (Parris, Grunebaum, Galfalvy, Andronikashvili, Burke, Yin, et al., 2018; Shao et al., 2018). Different gene expressions may contribute to separation anxiety and aggressive behavior in children carrying over into adulthood and lead to better mechanisms for intervention (Costa, Pini, Baldwin, Silove, Manicavasagar, Abelli, et al., 2017; Glenn, Lochman, Dishion, Powell, Boxmeyer & Qu, 2018; Leibowitz, Silverman, Martino, ZagoorySharon, Feldman Leckman, 2016). It was noted that women who sustained traumatic events as children, particularly sexual abuse and violent partner abuse impacted oxytocin levels precluding many mothers to experience depression and post partem depression impacting their ability to bond well with their infants (Lara-Cinisomo, Zhu, Fei, Bu, Weston & Ravat, 2008).

Human-Animal Interactions

Some humans find that going through a functional magnetic resonance imaging (fMRI) procedure to be challenging. But can you imagine a neuroscience experiment that attempts to challenge a dog’s obedience by putting her through the rigor of a fMRI procedure? A neuroscientist did, and despite naysayers thinking that he was going into a venture that would not work, he persisted, and his team reported useful information about the functional organization of cortical motor areas in adult dogs and puppies, and other revelations that until then were suspected but without scientific support (Berns, 2013). His findings triggered investigations into canine intelligence, cognitive skills and their neurobiological underpinnings, including oxytocin.

Earlier, Handlin, et al (2012) studied ten female owners of male Labrador Retrievers to see whether scores on the Monash Dog Owner Relationship Scale (MDORS) would correlate with levels of oxytocin and cortisol in both human and dog research subjects. Numeric data included scores on the MDORs’ item, subscale and total scores. Oxytocin and cortisol levels from both owners and dogs were analyzed from ten blood samples collected during the 60-minute interaction. The results showed a relationship between the owners’ oxytocin and cortisol levels and the affiliative characteristic of the human and the dog, e.g., high oxytocin levels on both dog and owner when owners kissed their dogs. A follow up study employed the same group of research subjects using a similar time frame and blood tests, but this time, the researchers videotaped the session (Petersson, et al, 2017). The entire experiment was videotaped, and the following variables were noted; different touches (stroking, stroking, scratching, patting and activating touch – a combination of scratching and patting). A second variable noted the frequency of touch by the owner and the frequency of touching performed by the owner, and finally, the dog’s position and time spent in each position. Correlational analysis showed: that owners with low oxytocin touched their dogs more frequently; the lower the dog’s oxytocin level, the more stroking they received from their owner; the more frequently the owner’s applied the combination of patting and scratching, the higher the dog’s cortisol level. The dog’s position level correlated conversely with the owner’s oxytocin level, i.e., high owner oxytocin, the less position changes; meanwhile, the higher the owner’s cortisol level, the longer time the dogs maintained the standing position.

Routine habits of dogs and their owners have been a subject of research investigation. One such study involves the mutual gaze in which owners and dogs engage. A study in Japan showed that in dogs increased their gazing behavior which then increased oxytocin levels in their owners (Nagasawa, et al, 2015). This increased the level of oxytocin in their owners bonding with the dogs, which then increased oxytocin levels in their dogs. The study also revealed that intranasal administration of oxytocin increased the dog’s gazing behavior which then increased urinary oxytocin levels in their owners. They concluded the loop that exists between dogs and human beings in the use of gazing behavior is a form of communication that leads to bonding. These findings support the existence of an interspecies oxytocin-mediated positive loop facilitated and modulated by gazing, which may have supported the coevolution of human-dog bonding by utilizing common modes of communicating social attachment.

A systematic review of studies on human animal interactions probed the evidence for the positive effects of pet ownership and animal support in education and therapeutic interventions. After reviewing 69 original studies that met their criteria of sample size, peer-review and methodology, Beets, et al (2012) concluded that there was documented evidence for the positive effects of human animal interaction for: “social attention, social behavior, interpersonal interactions, and mood; and measurement of cortisol, heart rate, and blood pressure, self-reported fear and anxiety, mental and physical health, especially cardiovascular diseases.”

Another study in another part of the world, this time in Finland, looked at the effect of oxytocin on the dog’s ability to recognize and interpreting threats, in this case a smiling and an angry face. The experiment required that 43 dogs were tested twice, once after administration of oxytocin, and the other without oxytocin in their system. Results showed that with oxytocin, the dogs appeared to be more interested in smiling faces and made them see angry faces to be less threatening. The study provides support that oxytocin which is commonly associated with affection and trust is probably a major factor in the interspecies interaction between humans and dogs (Somppi, et al, 2017). 

Summary & Reflections

This introspective article is a result of our exploration on oxytocin, its neurobiological mechanism, and how it influences sexual and other bonding and affiliative behaviors in men, women, and connectedness with animals. Reviewing scholarly and popular publications allowed translation into daily occupations and possibly in applications while interacting as occupational therapy practitioners. Pondering the literature, for example adds a layer of understanding the emotional loop that occurs when a mother breastfeeds her infant, including the ejection of milk during lactation, and the skin-to-skin contact that trigger the release of oxytocin on both mother and child. The same can be said in regulating the amount of pressure when touching someone and knowing that different people (dogs or other animals) can react with release of either cortisol or oxytocin. Remember that cortisol is a biochemical manifestation of stress that may result in an avoidance or a fight response from a life experience, while oxytocin promotes an affiliative experience. All of this is essential to know in order to read nonverbal behaviors of others and our animals in your personal and professional life.