Early Childhood Adversity Is a Key Risk Factor for Substance Abuse
Rather than choice, chance, or genetic predetermination, it is childhood adversity that creates the susceptibility for addiction.
In early childhood, research on the biology of stress shows how major adversity, such as abandonment, neglect, or abuse (emotional, physical, or sexual), can weaken the architecture of the developing brain and place the body’s stress response system on constant alert. Scientists also show that stable, responsive, nurturing relationships in the early years of life can prevent or even reverse the harmful effects of early life stress, with lifelong benefits for learning, behavior, and health.
A fourth brain-body system is involved in addiction: the stress response system. The other three dominant brain systems involved in addiction are: – opioids associated with the attachment-reward system, dopamine-based incentive and motivation system, and the self-regulatory areas of the prefrontal cortex – are all, to varying degrees, impaired in addicts.
The role of stable, caring relationships in the developing child
Parental nurturing during infancy is a key factor in the regulation of brain neurotransmitters, such as natural opioids, dopamine, serotonin, and norepinephrine, which are essential for controlling mood and behavior.
Positive and secure emotional interactions with caregivers stimulate the release of natural opioids in the child's brain. This surge of endorphins promotes the development of opioid and dopaminergic circuitry. In contrast, stress reduces the number of opioid and dopamine receptors, preventing the healthy growth of these crucial systems, responsible for connection, pain relief, pleasure, etc. The absence or scarcity of neurotransmitters leaves the child more vulnerable to “needing” drugs of abuse later in life to supplement what their brain is lacking.
Not only can early childhood experiences lead to a shortage of "good" chemicals in the brain, but also, to a dangerous overload of certain other substances. Maternal deprivation and other types of childhood adversity can lead to chronically high levels of the stress hormone cortisol. Excess cortisol shrinks important brain centers such as the hippocampus – a structure important for memory and emotional processing – and disrupts normal brain development in many other ways, with lifelong repercussions.
The role of childhood trauma and predisposition to addiction
Studies of drug addicts consistently report extraordinarily high percentages of childhood trauma of various sorts, including physical, sexual, and emotional abuse. In the renowned ACE (Adverse Childhood Experiences) study, researchers looked at the incidence of ten separate categories of painful circumstances – including family violence, parental divorce, drug or alcohol abuse in the family, death of a parent and physical or sexual abuse – in thousands of people. They then calculated the correlation between these conditions and substance abuse later in the subjects’ lives. For every adverse childhood experience, or ACE, the risk of early substance abuse increased by a factor of two to four. Subjects who had experienced five or more ACEs had a seven to ten times greater risk of substance abuse than those who had not.
Many addicts self-medicate to ease their emotional pain. They are much more vulnerable to the effects of mind-altering drugs and addiction. This is because their developing brain was initially sabotaged by their traumatic experiences. The systems subverted by the trauma – the opioid and dopamine circuits, the limbic or emotional brain, the stress apparatus, and the impulse control areas of the cortex – were not able to develop normally.
Overreaction of the stress response systems and "cross-sensitization" to addictive substances.
Early trauma also has consequences for how human beings respond to stress throughout their lives, and stress has everything to do with addiction.
Early stress sets a lower “stress threshold" for a child’s internal stress system: that child will get more readily stressed than normal throughout life. Dr. Bruce Perry stated in an interview that "a child who’s stressed early in life and whose baseline stress is already elevated will be more anxious, more distressed and more easily triggered".
A brain pre-set to be easily triggered into a stress response is likely to assign a high value to substances, activities and situations that provide short-term relief and less interest in long-term consequences. For example, contrast a person whose baseline physiological arousal is normal with someone whose baseline arousal is higher. Given alcohol, both may experience the same intoxicating effect, but the one with the higher level of physiological alertness will feel extra pleasure from the relief of that stress. It is analogous to drinking cool water with a parched throat: the pleasure effect is much heightened by the relief of thirst."
Conversely, situations or activities that, for the average person, are likely to bring satisfaction are undervalued because, in the addict's life, they were not rewarding – for example, intimate connections with family. This shrinkage from normal experience is also the result of early trauma and stress, as summarized in a psychiatric review of child development by Pederson CA in Ann N Y Acad Sci. 2004, 1036:106-127:
“Neglect and abuse during early life may cause bonding systems to develop abnormally and compromise capacity for rewarding interpersonal relationships and commitment to societal and cultural values later in life. Other means of stimulating reward pathways in the brain, such as drugs, sex, aggression, and intimidating others, could become relatively more attractive and less constrained by concern about violating trusting relationships. The ability to modify behavior based on negative experiences may be impaired.”
Chronic drug addicts, whose lives invariably began under conditions of intense stress, are all too easily drawn into a stress response. The stress response not only overwhelms the addict's ability to think rationally, which is already challenged by emotional turmoil, but the stress hormones cause "cross-sensitization" with addictive substances. The more one is present, the more the other is sought after. Addiction is a deep-seated reaction to stress, an attempt to cope with it through self-soothing. Ill-adapted in the long term, it is very effective in the short term.
Predictably, stress is a major cause of continued drug dependence. It increases opiate craving and use, reinforces the reward effectiveness of drugs, and provokes relapse to drug-seeking and drug-taking. Stressful experiences increase the vulnerability of the individual to either develop drug self-administration or relapse.
