Addiction And Its Physical Effects [History Of Opium: Part 9]


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““Addiction is a disease of pathological learning. It is a pathological usurpation of the neural mechanisms of learning and memory that under normal circumstances serve to shape survival behaviors related to the pursuit of rewards and the cues that predict them.”

– Dr. Steven Hyman, Harvard University

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The word addiction comes from Latin and means “enslaved by” or “bound to.” It is a complicated and chronic relapsing brain disease that is characterized by drug seeking and use despite adverse or harmful consequences. These negative consequences can manifest in health issues, legal problems, work or school related difficulties and financial repercussions. It is a biological disorder that is accompanied by minimization, rationalization, justification, blame and denial, and it plays out in three stages:

1. Preoccupation/anticipation
2. Binge/intoxication
3. Withdrawal/negative affect.

Despite the fact that addiction and alcoholism have been considered the result of character flaws or moral failings at different times in history, the disease concept has been recognized and championed by various authorities since Dr. Benjamin Rush, signer of the Declaration of Independence (and widely considered the father of American addiction treatment) asserted its validity at the time this country was founded nearly two hundred and fifty years ago.

Though the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) now uses the word “disorder” instead of addiction, the term still refers to substance-related disorders that stem from the use and abuse of everything from caffeine to cannabis to opioids. The DSM-5 defines it further by using the diagnostic criteria of mild, moderate or severe. Whatever the prevailing nomenclature, leading experts agree that addiction is a complex biological disorder with a genetic basis that is influenced by the environment.

Biologically speaking, addiction engages and affects many regions of the brain at different stages of its development. The three stages listed above can feed on each other and intensify over time, which leads to the pathological state of addiction. Initial consumption of the drug is likely voluntary, but (depending on the substance) use can escalate quickly to a loss of volitional control.

When opioids enter the bloodstream, they quickly make their way to the brain where they attach to opioid receptors and trigger the release of dopamine into the portion of the brain called the nucleus accumbens. Dopamine is a neurotransmitter that conveys a message to the brain that the behavior being engaged in is something that promotes survival. It is also released during activities like sex and eating. Tolerance to opioids is an unfortunate side effect of their use and brain cells that have been exposed to them repeatedly become less responsive to them over time. In addition to creating tolerance and initiating the reward system, the stress system is also activated. This is thought to be mediated by corticotropin releasing factor (a hormone involved in stress response). It is important to note that, as the addiction ramps up the rewards and stress systems, the executive function dampens, which renders the addict unable to make choices and perceive consequences. Tolerance ultimately requires the user to take more and more drugs to achieve a desired response or even to feel “normal.”

Opioids don’t damage the brain like other drugs, but they can permanently alter or change the brain. Repeated exposure to an addictive drug eventually rewires nerve cells in the nucleus accumbens and pre-frontal cortex to communicate in a way that couples liking something with wanting something; at this point in the addiction, the distinction between the two ceases to exist. Normal motivational processes are no longer in play because even though the pleasure associated with the drug has subsided, the memory and need to recreate it (the wanting) persists. Addiction occurs when the intense liking disappears, but the wanting stays; despite the fact that the addict knows that using the drug will likely be detrimental, the feeling of wanting it overrides everything.

The genetic component of addiction is also very strong. Studies show that sixty percent of a person’s vulnerability to addiction is related to genes. Several candidate genes have been identified, and it will undoubtedly be discovered that several are responsible, but one thing is fairly certain – possessing these genes serves some adaptive advantage – in spite of the negative behaviors that may accompany them.

Environmental influences play an integral role in addiction, but two factors are absolutely critical when it comes to determining who is at risk: brain development during infancy and childhood trauma. How the brain develops in the first two years of life is crucial, and virtually completely reliant on the baby’s relationship with its primary caregiver. If the child’s needs are not appropriately met during this crucial period, an overactive stress response system may result. Chemicals that are necessary for normal brain growth and function may be deficient and cause impairments of affect regulation, motivation, reward and behavioral inhibition. If these systems are compromised, social relationships can be affected and increase the likelihood of developing an addictive disorder.

Trauma and childhood victimization accounts for a large portion of addicts and is the single most inciting influence for addiction. The Adverse Childhood Experiences study (2004) revealed that traumatic experiences result in neurodevelopmental changes and emotional damage that creates strong motivation for seeking relief through psychoactive substance abuse. Trauma can diminish the brain’s ability to make new connections and result in the injured person’s inability to form normal and vital bonds with other people. The shattering of these processes deprives the victim of the opportunity to develop the capacity to regulate emotions adequately.

People take drugs to feel good, feel better, perform better and out of curiosity. If addiction occurs, the brain can be forever altered. Young people should be especially careful, as developing brains are particularly vulnerable to the insults of opioids. While there is no single risk factor, biology, genetics and environment all play important roles in determining who develops an addiction. Our brains are wired to ensure that we will repeat life-sustaining activities by associating them with pleasure or reward. Drug addiction wreaks havoc on the brain systems that deal with pleasure and reward and once these areas have been compromised, judgment, decision-making, learning, memory and behavioral control are all at risk of being permanently altered.

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Koob, George F., Ph.D., Simon, Dr. Eric J., “The Neurobiology of Addiction:  Where We Have Been and Where We Are Going,” Journal of Drug Issues, January, 2009, 
Kosten, MD, Thomas R., George, MD, Tony P., “The Neurobiology of Opioid Dependence:  Implications for Treatment,” Science and Practice Perspectives, July, 2002, 
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How Addiction Hijacks the Brain,” Harvard Health Publishing, July, 2011,
What is Addiction?
What Causes Addiction?
Addiction And Its Physical Effects [History Of Opium: Part 9]
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Michelle Poe

Posted by Michelle Poe, a writer for Enjoy posts from guests and experts on life’s important topics. This website is for informational and/or entertainment purposes only and is not a substitute for medical advice, diagnosis, or treatment.
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