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05-20-2015, 08:51 PM
Just in case, I thought some people might be interested in some of the papers I was writing for school. This might actually begin to touch on dreaming some time down the road, but for now, it's more oriented to brain chemistry and addictions. This was just a discussion question, so it's not chock full of statistical research. If you or someone you know is addicted, they MIGHT benefit from this brief discussion.
Having grown up in an alcoholic family, causation has always been on the forefront of my mind. That is, what exactly causes people to become addicted to substances, arousal, or repetitive behaviors? Certainly, I couldn’t possibly answer that broad and complex question in this format, but I think one of the most fundamental aspects of addiction causality is this concept called, “the reward pathway.”
In the Beginning…
The main premise behind the reward pathway is that there are actual physical and chemical processes in the brain that, at a minimum, could exacerbate one’s risk of becoming and staying addicted. We begin our tour inside the limbic system, which, among many other important functions, is well known for its role in human emotion. The reward pathway is said to begin in the Ventral Tegmental Area (VTA), which is physically located near the top of the brain stem. This is one of the few locations in the human brain where dopamine apparently originates. D2 (dopamine) is the main ingredient for those “high” feelings and pleasurable sensations (e.g., an orgasm).
The neurons in the VTA have axons that extend into the Nucleus Accumbens, and so we thus have the first portion of our reward pathway fully connected. The dopamine neurotransmitter fires up in the brain stem (VTA) and gets excreted to the receptor sites in the Nucleus Accumbens. The reason this is important is because we now have our first potential cause for addiction: “Many people who, for a genetic error, have a reduction of D2 (dopamine) receptors in the accumbens nucleus, become, sooner or later, incapable to obtain gratification from the common pleasures of life” (Rocha do Amral & Martins de Oliveira, n.d.),
In laymen’s terms, the pre-addicted person, for one of numerous possible reasons, is incapable of producing the necessary ingredients to ‘feel really good.’ This makes them vulnerable to substances that artificially boost D2 levels. For example, cocaine blocks the re-uptake of D2 and thus artificially increases the concentration of said neurotransmitter in the synaptic cleft. As an aside, the action of prohibiting re-uptake is precisely what is done in many of today’s anti-psychotic pharmaceuticals. This reaction is important for the reward pathway, especially when talking about tolerance.
Tolerance
More specifically, the body reacts to the increased dopamine concentrations by trimming its authentic production of it. So, even though the dopamine felt good, the body attempts to return itself to balance, and thus begins tailoring back its D2 production (even though it knows that reduced dopamine will not feel nearly as good—the body is seeking balance!) Thus, it now requires more cocaine to get the same D2 concentrations in the synaptic cleft. This would also explain why SSRIs and other re-uptake drugs can become ineffective or even dangerous in the long term.
My somewhat informal discussion of tolerance was a bit simplistic, for there are a couple of more scientific processes that are happening here: metabolic and functional. “Metabolic tolerance occurs when the body becomes so adapted to the presence of a drug that a given amount of the substance will produce less of an effect than when the user first tried the drug” (Derby, n.d.). In other words, the body begins adapting to the chemical by adjusting its numerous biological processes, which might include extorting the liver to produce more of a certain enzyme to ‘eat up’ the ingested toxin. On the other hand, pharmacodynamics (or functional) tolerance exists more in the neuron itself. Transmitters and receptors will exhibit morphed behaviors based on the dynamics incurred by the ingested toxin. Again, these processes are a direct result of the body’s broader homeostasis mechanisms.
Before we move on to the last component in the reward pathway, it is important to note that despite psychiatry’s incessant rebuke of natural cures, there are, indeed, other more natural ways to increase the various neurotransmitter in the human body. For example, “Tryptophan is the amino acid precursor for serotonin; phenylalanine and tyrosine are precursors for dopamine and norepinephrine” (Marohn, 2011, p. 40). So, instead of unnaturally closing off re-uptake channels to artificially boost certain ‘feel good’ neurotransmitters, it is possible to naturally increase neurotransmitter production through the use amino acid supplementation (‘production’ is highlighted because in this modality, one is not artificially boosting the neurotransmitter but rather giving the body the natural precursors to help the brain create its own neurotransmitter). However, I haven’t been able to find any studies on the efficacy of using this approach specifically with substance addictions. One reasonable hypothesis, especially with the lack of harmful side effects, is that if amino acids can all-out cure severe psychiatric mood disorders, it might be able to do the same for psychological woes in addicted patients.
Don't Forget About the Prefrontal Cortex
The last component of the reward pathway is the prefrontal cortex. This area is critical for several reasons. First, while the addict is intoxicated or ‘high,’ this cortex area is directly impacted, and so the affected person might experience degraded coordination and memory. Secondly, the substance can actually affect the person’s ability to learn, both in the intoxicated state and the withdrawal state. In fact, the dynamics happening in this area could very well explain why addicts and alcoholics have such a loss of control. In 2008, Yin published a possible connection between drug addiction and brain plasticity (or the person’s ability to change and adapt to outside stimuli). Specifically, the reward pathway eventually degrades the biochemical processes needed in order to learn and adapt, which would completely explain why addicts and alcoholics find it impossible to change their ways despite having already lost their family, house, and/or job (Capuzzi & Stauffer, 2012).
In closing, the addictive process can be much more physically and chemically based than many people previously estimated. The biochemical processes are just now being unearthed, and they provide revolutionary understanding about how addicts get started and get stuck. Further research promises to elucidate avenues to stop this reward pathway from becoming a runaway freight train. It certainly won’t be easy, for addictions encompass just about every factor imagined and probably can’t ever be reduced to just the reward pathway in and of itself. Nonetheless, I believe the reward pathway is one of the most important concepts in the broader addictions-recovery processes.
References
Capuzzi, D., & Stauffer, M. D. (2012). Foundations of addictions counseling, 2nd ed. Upper Saddle River, NJ: Pearson Education, Inc.
Derby. (n.d.). Addiction: The development of tolerance. Retrieved from http://www2.derby.ac.uk/ostrich/intro_to...age_05.htm
Marohn, S. (2011). The natural medicine guide to bipolar disorder. Charlottesville, VA: Hampton Roads.
Rocha do Amaral, J., & Martins de Oliveira, J. (n.d.) Limbic System: The center of emotions. Retrieved from http://www.healing-arts.org/n-r-limbic.htm
Having grown up in an alcoholic family, causation has always been on the forefront of my mind. That is, what exactly causes people to become addicted to substances, arousal, or repetitive behaviors? Certainly, I couldn’t possibly answer that broad and complex question in this format, but I think one of the most fundamental aspects of addiction causality is this concept called, “the reward pathway.”
In the Beginning…
The main premise behind the reward pathway is that there are actual physical and chemical processes in the brain that, at a minimum, could exacerbate one’s risk of becoming and staying addicted. We begin our tour inside the limbic system, which, among many other important functions, is well known for its role in human emotion. The reward pathway is said to begin in the Ventral Tegmental Area (VTA), which is physically located near the top of the brain stem. This is one of the few locations in the human brain where dopamine apparently originates. D2 (dopamine) is the main ingredient for those “high” feelings and pleasurable sensations (e.g., an orgasm).
The neurons in the VTA have axons that extend into the Nucleus Accumbens, and so we thus have the first portion of our reward pathway fully connected. The dopamine neurotransmitter fires up in the brain stem (VTA) and gets excreted to the receptor sites in the Nucleus Accumbens. The reason this is important is because we now have our first potential cause for addiction: “Many people who, for a genetic error, have a reduction of D2 (dopamine) receptors in the accumbens nucleus, become, sooner or later, incapable to obtain gratification from the common pleasures of life” (Rocha do Amral & Martins de Oliveira, n.d.),
In laymen’s terms, the pre-addicted person, for one of numerous possible reasons, is incapable of producing the necessary ingredients to ‘feel really good.’ This makes them vulnerable to substances that artificially boost D2 levels. For example, cocaine blocks the re-uptake of D2 and thus artificially increases the concentration of said neurotransmitter in the synaptic cleft. As an aside, the action of prohibiting re-uptake is precisely what is done in many of today’s anti-psychotic pharmaceuticals. This reaction is important for the reward pathway, especially when talking about tolerance.
Tolerance
More specifically, the body reacts to the increased dopamine concentrations by trimming its authentic production of it. So, even though the dopamine felt good, the body attempts to return itself to balance, and thus begins tailoring back its D2 production (even though it knows that reduced dopamine will not feel nearly as good—the body is seeking balance!) Thus, it now requires more cocaine to get the same D2 concentrations in the synaptic cleft. This would also explain why SSRIs and other re-uptake drugs can become ineffective or even dangerous in the long term.
My somewhat informal discussion of tolerance was a bit simplistic, for there are a couple of more scientific processes that are happening here: metabolic and functional. “Metabolic tolerance occurs when the body becomes so adapted to the presence of a drug that a given amount of the substance will produce less of an effect than when the user first tried the drug” (Derby, n.d.). In other words, the body begins adapting to the chemical by adjusting its numerous biological processes, which might include extorting the liver to produce more of a certain enzyme to ‘eat up’ the ingested toxin. On the other hand, pharmacodynamics (or functional) tolerance exists more in the neuron itself. Transmitters and receptors will exhibit morphed behaviors based on the dynamics incurred by the ingested toxin. Again, these processes are a direct result of the body’s broader homeostasis mechanisms.
Before we move on to the last component in the reward pathway, it is important to note that despite psychiatry’s incessant rebuke of natural cures, there are, indeed, other more natural ways to increase the various neurotransmitter in the human body. For example, “Tryptophan is the amino acid precursor for serotonin; phenylalanine and tyrosine are precursors for dopamine and norepinephrine” (Marohn, 2011, p. 40). So, instead of unnaturally closing off re-uptake channels to artificially boost certain ‘feel good’ neurotransmitters, it is possible to naturally increase neurotransmitter production through the use amino acid supplementation (‘production’ is highlighted because in this modality, one is not artificially boosting the neurotransmitter but rather giving the body the natural precursors to help the brain create its own neurotransmitter). However, I haven’t been able to find any studies on the efficacy of using this approach specifically with substance addictions. One reasonable hypothesis, especially with the lack of harmful side effects, is that if amino acids can all-out cure severe psychiatric mood disorders, it might be able to do the same for psychological woes in addicted patients.
Don't Forget About the Prefrontal Cortex
The last component of the reward pathway is the prefrontal cortex. This area is critical for several reasons. First, while the addict is intoxicated or ‘high,’ this cortex area is directly impacted, and so the affected person might experience degraded coordination and memory. Secondly, the substance can actually affect the person’s ability to learn, both in the intoxicated state and the withdrawal state. In fact, the dynamics happening in this area could very well explain why addicts and alcoholics have such a loss of control. In 2008, Yin published a possible connection between drug addiction and brain plasticity (or the person’s ability to change and adapt to outside stimuli). Specifically, the reward pathway eventually degrades the biochemical processes needed in order to learn and adapt, which would completely explain why addicts and alcoholics find it impossible to change their ways despite having already lost their family, house, and/or job (Capuzzi & Stauffer, 2012).
In closing, the addictive process can be much more physically and chemically based than many people previously estimated. The biochemical processes are just now being unearthed, and they provide revolutionary understanding about how addicts get started and get stuck. Further research promises to elucidate avenues to stop this reward pathway from becoming a runaway freight train. It certainly won’t be easy, for addictions encompass just about every factor imagined and probably can’t ever be reduced to just the reward pathway in and of itself. Nonetheless, I believe the reward pathway is one of the most important concepts in the broader addictions-recovery processes.
References
Capuzzi, D., & Stauffer, M. D. (2012). Foundations of addictions counseling, 2nd ed. Upper Saddle River, NJ: Pearson Education, Inc.
Derby. (n.d.). Addiction: The development of tolerance. Retrieved from http://www2.derby.ac.uk/ostrich/intro_to...age_05.htm
Marohn, S. (2011). The natural medicine guide to bipolar disorder. Charlottesville, VA: Hampton Roads.
Rocha do Amaral, J., & Martins de Oliveira, J. (n.d.) Limbic System: The center of emotions. Retrieved from http://www.healing-arts.org/n-r-limbic.htm