Part 1

I am quite excited by these recent discoveries in oxytocin as they appear to offer some explanation for one question that has been with me for nearly ten years, why do alcoholics especially feel like they have a “hole in the soul”. As a adolescent this felt almost physical this feeling as it did for many other alcoholics.

It is probably the main and most common description I have heard from recovering alcoholics about how they felt in themselves prior to starting to drink alcohol.

If so many alcoholics have felt this way, then maybe some neurobiological deficit creates or contributes to this feeling of having a hole in the soul perhaps highlighting a particular risk factor of later alcoholism, especially as oxytocin appears to interact directly and indirectly with the other main brain chemicals involved in the progression of alcoholism.

In a previous blog  we looked at how early external influences (like stress, social adversity) affect the developing endogenous oxytocin system, changing receptors, hardware and set points. This results in individual differences in oxytocin levels, and altered responsiveness of the oxytocin system. This disturbed development can lead to increased susceptibility to the development of addiction, and reduced resilience to stress.

Early influences also affect the other systems that the oxytocin system interacts with, such as neurotransmitter systems (like dopamine, serotonin, glutamate and GABA), the immune system, and the stress axis (Fig. 2). Specific sensitive periods exist for all these systems where external influences can have long-lasting effects after birth, but also during adolescence. Individuals may show only minor differences in behaviour and function unless subsequent stressors, or drug use, challenges the system again. This is when the increased susceptibility to addiction becomes apparent. Since these systems are all inter-dependent and regulate each other, early life adversity can change the balance of this entire system.

A well-developed oxytocin system is in a position to directly and indirectly increase resilience, for example by reducing drug reward, increasing social reward, reducing anxiety and reducing stress response. A well-developed system that is able to respond in times of stress, as well as social support, may decrease the chance that someone escalates their use and relapses when they have attempted to quit. If adversity is encountered, the oxytocin system still develops, but basal levels might be lower and it might be less responsive. Connectivity might be different with other systems. In short, individual differences in the endogenous oxytocin system may arise based on early life experiences.

Now we look at some mother-child interactions which may effect the changes in the oxytocin system which may have long lasting effects in terms of addiction.

The purpose of this paper (1) is to provide an overview of the neurobiological basis of maternal caregiving, in order to better understand how to prevent and respond to maternal neglect. Drawing from both animal and human studies, key biological systems are identified which contribute to maternal caregiving behavior, focusing on the oxytocinergic and dopaminergic systems. Mesocorticolimbic and nigrostriatal dopamine pathways contribute to the processing of infant-related sensory cues leading to a behavioral response. Oxytocin may activate the dopaminergic reward pathways in response to social cues.

For example, in insecure/dismissing attachment, which may be associated with emotional neglect, we see reduced activation of the mesocorticolimbic dopamine reward system in response to infant face cues, as well as decreased peripheral oxytocin response to mother-infant contact.

Interestingly, nationwide data from the United States suggests that the most frequent perpetrator of child neglect is the biological mother(1), with maternally perpetrated neglect noted in almost 80% of substantiated episodes (11). In one respect this is not surprising, given that the biological mother is most often the primary caregiver—a role integrally associated with the definition of neglect (12).

However, this is despite evidence that biological mothers may be primed, through the neuroendocrine changes associated with pregnancy, parturition and lactation, to provide optimal nurturance and protection to their offspring (11, 13). For example, the hormonal changes associated with pregnancy may induce neural modifications within the hippocampus (14) that facilitate various aspects of maternal caregiving, such as learning, spatial memory (13, 15) and emotion processing of facial cues (16).

Likewise, postnatal infant stimuli, including facial expressions, cries, and tactile/suckling stimulation, may also help to re-shape the maternal brain during a period of inherent neural plasticity (13). Maternal experience upregulates oxytocin receptor expression in the brain (17), and oxytocin, released during parturition and lactation, appears to exert long-term anxiolytic and bonding effects through changes in specific brain regions (18–21). As such, oxytocin may mediate the association between breastfeeding and lower rates of maternal neglect (11). Understanding the biological processes underlying maternal caregiving may help us to better understand how a disruption to these processes may contribute to maternal neglect.

On the most basic level, child neglect is defined as a failure to provide for a child’s intrinsic needs (22), whether physical or emotional (Figure 1). Physical neglect includes a failure to provide adequate nutrition, clothing, hygiene, medical care or educational provision. Emotional (or psychological) neglect involves a lack of emotional warmth, physical affection and nurturance, or ignoring signs of needed comfort or attention. Most neglected children experience a combination of physical and emotional neglect, often manifest in multi-problem, crisis-prone and chaotic families, in which unregulated affect motivates and organizes behavior, and maternal caregiving responses are unpredictable. In other families, parents may be withdrawn, unresponsive and unmotivated, while unable to perceive or respond to their children’s cues for attention (23).

However, some children may experience isolated physical neglect without emotional neglect, such as in the case of extreme poverty or socioeconomic disadvantage (3). Parents may be emotionally responsive to their children, but unable to meet the more “cognitive” demands of organizing and coordinating necessary care, such as in providing regular meals, medical care or meeting educational needs.

Emotional neglect may result in even more serious long-term consequences for a child’s social and emotional development (8, 26, 27). One longitudinal study of mother-infant dyads examined the effect of differing types of neglect on behavioral and cognitive outcomes (27). At 3 years of age, emotional neglect was found to be the only type associated with externalizing or internalizing behavior problems.

While most researchers and clinicians define child neglect in terms of a child’s basic unfulfilled needs, others have conceptualized the problem in terms of how a caregiver’s brain processes sensory information, and associated differences in adult attachment strategies (23, 29). It has been hypothesized that emotional neglect results from deficits in a mother’s affective information processing, with a bias toward cognitive processing. Physical neglect may be the end result of deficits in cognitive information processing (see Figure 1).

Maternal neglect: A disorder of mother-infant attachment?

After studying the associations between maternal neglect and juvenile delinquency, John Bowlby first formulated his attachment theory, postulating a universal human need to form close affectional bonds, primarily between mother and infant (30). He strongly argued, from an evolutionary perspective, that attachment was an innate biological system promoting proximity seeking between an infant and a specific attachment figure, in order to increase the likelihood of survival to a reproductive age. As a result of this powerful biological instinct, he hypothesized that all human infants become attached to their caregiver—even if the care is harsh or neglectful—but that these children manifest different patterns of attachment “security”.

Infants of caregivers who are available, responsive and sensitive to their emotional and physical needs tend to manifest patterns of “secure attachment”. However, if the care provided is chaotic, unpredictable, rejecting, or neglectful, infants develop self-protective strategies manifest as various “insecure” patterns of attachment.

“dismissing” adults tend to minimize affective information, dismiss their own feelings, intentions and perspectives  (25). Studies have also shown that “dismissing” mothers score much lower on measures of parental warmth and responsivity (35, 36), suggesting that this pattern of attachment may be associated with emotional neglect (23). “Preoccupied” adults, in contrast, organize their behavior around affective information, such as fear, anger, or desire for comfort. They tend to be preoccupied with their own feelings and perspectives.

Adults with secure patterns of attachment are able to integrate temporally ordered information regarding cause and effect, as well as affective information (emotional states, imaged memory, etc.), in order to form close relationships, make accurate decisions and predict future reward (25).”

Already for this paper we are observing certain major points which are applicable to later addiction – the internalising and externalising behaviours are said to be the main pathways into addiction from adolescence, and also in the later sections we are observing the organizing  of “behavior around affective information, such as fear, anger, or desire for comfort. They tend to be preoccupied with their own feelings and perspectives. ”

How accurate is this in describing the later addicted individual? Perhaps this initially contributes to the initial “fixing of feeling” in early use, i.e the desire for comfort borne out of a desire to alleviate negative emotional states?

More and more it appears that insecure attachment has a profound role to play in later addiction.

TBC

References

1. Strathearn, L. (2011). Maternal Neglect: Oxytocin, Dopamine and the Neurobiology of Attachment. Journal of Neuroendocrinology, 23(11), 1054–1065. doi:10.1111/j.1365-2826.2011.02228.x