Addiction – It’s Many Faces – Part II

by Dr. George Crabb on February 5, 2014 · 0 comments

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Introducing the Human Brain

The human brain is the most complex organ in the body.  This three-pound mass of gray and white matter sits at the center of all human activity-you need it to drive a car, to enjoy a meal, to breathe, to create an artistic masterpiece, and to enjoy everyday activities.  In brief, the brain regulates your basic body functions; enables you to interpret and respond to everything you experience; and shapes your thoughts, emotions, and behavior.

The brain is made up of many parts that all work together as a team.  Different parts of the brain are responsible for coordinating and performing specific functions.  Drugs can alter important brain areas that are necessary for life-sustaining functions and can facilitate the compulsive drug desires that make an individual continue to seek drugs. Even though the brain tissue craves the continued use of the drugs it is still the choice of the individual whether they will or will not take the drug.  Brain areas affected by drug abuse-

The brain stem controls basic functions critical to life, such as heart rate, breathing, and sleeping.

The limbic system contains the brain’s reward circuit-it links together a number of brain structures that control and regulate our ability to feel pleasure.  In addition, the limbic system is responsible for our perception of other emotions, both positive and negative, which explains the mood-altering properties of many drugs.

 The cerebral cortex is divided into areas that control specific functions.  Different areas process information from our senses, enabling us to see, feel, hear, and taste.  The front part of the cortex, the frontal cortex or forebrain, is the thinking center of the brain; it powers our ability to think, plan, solve problems, and make decisions.

How Does the Brain Communicate?

The brain is a communication center consisting of billions of neurons, or nerve cells.  Networks of neurons pass messages back and forth to different structures within the brain, the spinal column, and the peripheral nervous system.  These nerve networks coordinate and regulate everything we feel, think, and do.

 Neuron to Neuron

Each nerve cell in the brain sends and receives messages in the form of electrical impulses.  Once a cell receives and processes a message, it sends it on to other neurons.

 Neurotransmitters-The Brain’s Chemical Messengers

The messages are carried between neurons by chemicals called neurotransmitters.  (They transmit messages between neurons.) Some of the neurotransmitters are: dopamine, serotonin, epinephrine and nor-epinepherine amongst others.

 Receptors-The Brain’s Chemical Receivers

The neurotransmitter attaches to a specialized site on the receiving cell called a receptor.  A neurotransmitter and its receptor operate like a “key and lock,” an exquisitely specific mechanism that ensures that each receptor will forward the appropriate message only after interacting with the right kind of neurotransmitter.

 Transporters-The Brain’s Chemical Recyclers

Located on the cell that releases the neurotransmitter, transporters recycle these neurotransmitters (i.e., bring them back into the cell that released them), thereby shutting off the signal between neurons.

 How Do Drugs Work in the Brain?

Drugs and alcohol are chemicals.  They work in the brain by tapping into the brain’s communication system and interfering with the way nerve cells normally send, receive, and process information.  Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter.  This similarity in structure “fools” receptors and allows the drugs to lock onto and activate the nerve cells.

Although these drugs mimic brain chemicals, they don’t activate nerve cells in the same way as a natural neurotransmitter, and they lead to abnormal messages being transmitted through the network.

Other drugs, such as amphetamine or cocaine, can cause the nerve cells to release abnormally large amounts of natural neurotransmitters or prevent the normal recycling of these brain chemicals.  This disruption produces a greatly amplified message, ultimately disrupting communication channels.  The difference in effect can be described as the difference between someone whispering into your ear and someone shouting into a microphone.

 How Do Drugs Work in the Brain to Produce Pleasure?

All drugs of abuse directly or indirectly target the brain’s reward system by flooding the circuit with dopamine.  Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, cognition, motivation, and feelings of pleasure.  The overstimulation of this system, which rewards our natural behaviors, produces the euphoric effects sought by people who abuse drugs and urges them to repeat the behavior.

Why Are Drugs More Addictive than Natural Rewards?

When some drugs of abuse are taken, they can release 2 to 10 times the amount of dopamine that natural rewards do.  In some cases, this occurs almost immediately (as when drugs are smoked, snorted or injected), and the effects can last much longer than those produced by natural rewards.  The resulting effects on the brain’s pleasure circuit dwarfs those produced by naturally rewarding behaviors such as eating and sex.  The effect of such a powerful reward strongly motivates people to take drugs again and again.  This is why drug abuse is something we learn to do very, very well by making continuously bad choices.

 What Happens to Your Brain if You Keep Taking Drugs?

Just as we turn down the volume on a radio that is too loud, the brain adjusts to the overwhelming surges in dopamine (and other neurotransmitters) by producing less dopamine or by reducing the number of receptors that can receive and transmit signal.  As a result, dopamine’s impact on the reward circuit of a drug abuser’s brain can become abnormally low, and the ability to experience any pleasure is reduced.  This is why the abuser eventually feels flat, lifeless, and depressed, and is unable to enjoy things that previously brought them pleasure.  Now, they need to take drugs just to bring their dopamine function back up to normal.  And, they must take larger amounts of the drug than they first did to create the dopamine high-an effect known as tolerance.

 How Does Long-Term Drug Taking Affect Brain Circuits?

We know that the same sort of mechanisms involved in the development of tolerance can eventually lead to profound changes in neurons and brain circuits, with the potential to severely compromise the long-term health of the brain.  For example, glutamate is another neurotransmitter that influences the reward circuit and the ability to learn.  When the optimal concentration of glutamate is altered by drug abuse, the brain attempts to compensate for this change, which can cause impairment in cognitive function.  Similarly, long-term drug abuse can trigger adaptations in habit or non-conscious memory systems.

 What Are The Medical Consequences Of Drug Addiction?

Individuals who suffer from addiction often have one or more accompanying medical issues, including lung and cardiovascular disease, stroke, cancer, and mental disorders.  Imaging scans, chest x-rays, and blood tests show the damaging effects of drug abuse throughout the body.  For example, tests show that tobacco smoke causes cancer of the mouth, throat, larynx, blood, lungs, stomach, pancreas, kidney, bladder, and cervix.  In addition, some drugs of abuse, such as inhalants, are toxic to nerve cells and may damage or destroy them either in the brain or the peripheral nervous system.

 What Is The Answer?

The answer to this very complicated issue is simply a personal relationship with Jesus Christ. We can help the addicted physically by proper medical care and intervention but the foundation to the recovery is accepting Jesus Christ as your personal Saviour and then daily developing a dynamic personal relationship with Him. All other programs fall short of true freedom for only in Jesus can an individual be “made free.”

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