The Effects of Methamphetamine on the Brain Dustin Fry
To understand how a person feels pleasure and pain we need to understand the way neurotransmitters work. When a person drinks a cup of coffee, ingests a sleeping pill, or does a drug like meth, that person's neurotransmitter levels can be affected. Neurotransmitters are essentially the brain’s chemical messengers that work together to perform many different tasks. The neurotransmitter systems that we will be focusing on are dopamine, norepinephrine, epinephrine, and serotonin. These transmitters are all affected by meth and can suffer long-lasting damage even after just one trial with this dangerous drug.
Methamphetamine’s chemical structure closely resembles these neurotransmitters. Meth affects these neurotransmitters either by increasing chemical release, or by stopping the metabolism (breakdown) and re-uptake of these neurochemicals. Meth can also bind to the nerve receptors and confuse the brain by mimicking certain neurotransmitters. This chain of events creates a dangerous chemical imbalance within the brain, resulting in necrosis (nerve cell death) and nerve cell structural change.(Wilson,2006) The brain has different safety mechanisms to protect against imbalances of neurochemicals, but meth shuts down these safety mechanisms. And shutting down these safety mechanisms can ultimately result in nerve cell death. The dopamine system is a good place to examine the ways that meth alters a person’s mind.
Dopamine (DA) is the neurotransmitter that plays a part in controlling movement, thought processes, emotions, and the pleasure centers of the brain. When a person physically works out or accomplishes a difficult task, the brain releases excess dopamine into certain areas of the brain. Any release of dopamine induces a sense of euphoria and well being. When a person takes meth, a chain of events occurs at the dopamine synapses . (Weiten 2008)
When meth stimulates these transmitters to excessively release dopamine into many different areas of the brain, the safety mechanism would normally react by reabsorbing and transporting the excess chemicals back into the synaptic vessels, but meth blocks dopamine re-uptake, and a gradual chemical buildup occurs.
This chemical buildup has many different effects on a person's behavior. For the meth user the chemical buildup resembles a dangerous rollercoaster ride. As dopamine levels rise in the brain, so do the feelings of euphoria. This initial buildup is like the start of the rollercoaster. When the drug finally wears off, and the dopamine levels gradually decrease, the meth user plunges to the bottom of this ride losing all the feelings of euphoria and well being. These euphoric feelings will not return until the dopamine system is once again stimulated. Dopamine is responsible for reinforcement behaviors. Reinforcement is a psychological term that refers to a stimulus that strengthens or weakens the behavior that produced it. (Covey 2006) For example you might train your dog to do tricks by reinforcing the desired behavior with a stimulus of food. Meth short-circuits dopamine levels, directly influencing reinforcement behaviors, and actually induces drug-seeking behaviors. For the meth user, the euphoria is the stimulus that induces the drug-seeking behavior.
Studies have shown that meth overdoses are almost indistinguishable from those behaviors exhibited by a Type I schizophrenic. Type I schizophrenic behavior includes psychotic episodes, delusions, hallucinations, hearing voices, and extreme paranoia. The imbalance of dopamine levels causes this schizophrenic-like behavior that wears off within a couple days after use has ended. This overload of dopamine in the brain can even lead to further problems. Meth is toxic to dopamine synapses and their associated nerve cells in the brain. Long-term abuse of meth causes dopamine nerve axons to eventually wither and die. When these synaptic nerve endings die, they are gone for good. The abuser's emotions, pains, and pleasures will be permanently and irreversibly altered. The meth user's world becomes one notch grayer, and events seem one notch duller.
Norepinephrine (NE) is a neurotransmitter that plays a part in controlling alertness, rest cycles, attention, and memory. So if you are reading this article, and are having trouble concentrating, it could be because your brain is currently not producing enough norepinephrine. Going to get some coffee would help you to raise these levels, allowing concentration to return. Norepinephrine is also called noradrenalin. Noradrenalin is the main chemical used by the body for the synthesis of the hormone adrenaline. This neurotransmitter has been studied in depth by scientists, and plays a key role in many complex brain functions. From the previous explanation of how meth affects dopamine chemicals at the synapse, one can easily understand the detrimental influence of meth on the norepinephrine system. As seen with the dopamine system, the drug meth can influence norepinephrine transmitters by blocking the re-uptake mechanism. However, the main difference between the dopamine and norepinephrine systems is that meth does not stimulate excess chemical release at the norepinephrine synapses. (Covey 2006)
Another difference between the dopamine and norepinephrine systems is that meth is not neurotoxic to the norepinephrine system synapses and receptors. Meth can stimulate increases in the growth of the norepinephrine nerve. This growth does not mean that the brain becomes more efficient at administering norepinephrine chemicals to the different areas of the brain as a result of this cancerous expansion. This growth could be partially responsible for the short-circuiting of the brain, and directly responsible for the chemical imbalance that is associated with meth usage.
Epinephrine System Adrenaline is a hormone that we are all familiar with. When you encounter an exciting or intense situation, stores of adrenaline are released into the blood stream and a rush instantaneously occurs. For example, when you are about to run a race at a track meet, you can feel the nervous energy as the adrenaline is released. A fact that is not readily apparent is that adrenaline also plays a minor role in our brain as a neurotransmitter. The scientific term for this hormone/neurotransmitter is epinephrine (E). Epinephrine’s importance as a chemical messenger becomes evident when a drug like meth declares a territorial war in the synaptic gap (the space in between the nerve transmitter and nerve receptor).
Meth influences epinephrine transmitters by blocking the re-uptake mechanism. As seen with dopamine and norepinephrine, a blocked re-uptake mechanism results in excess chemicals floating in the synaptical gap. The meth user's physical and mental overexertion is hardly noticeable as the brain's receptors hungrily absorb the extra chemicals. This excess of epinephrine surging to different areas of the brain is partially responsible for the increased energy and rush that the meth user feels. Meth users lose their appetite as a direct result of having excess epinephrine chemicals in circulation. The user loses weight as their body feeds off the empty energy of this continual adrenaline rush while they are not even thinking about taking the time to eat. Meth is a drug that lab rats will take instead of eating food, and they will die of starvation when food is right under their nose.
Epinephrine also plays a role in the crash that is associated with meth use. The crash is more noticeable in meth abusers who have used the drug for many days in a row, and their adrenaline stores are thoroughly depleted. But this depletion also happens with first time and recreational users.
The process of epinephrine depletion in a meth user is similar to the process of a car whose acceleration pedal is superglued to the floor. The meth user’s mind and body are working at a high speed, just like the engine of that car would run at high speed. The meth user’s epinephrine system is wasting stores of epinephrine, just like the superglued accelerator is recklessly burning stores of gas. Eventually the user depletes his epinephrine supply because he hasn’t rested, just like the car would eventually stop because its tank is empty. With epinephrine store depletion, the crash is the resulting complication, and the user’s body has to rest until adrenaline stores are replenished.
Serotonin System Serotonin (5-HT) is the last of the neurotransmitters that we will be studying. Serotonin plays an important role in many behaviors including sleep, appetite, memory, sexual behavior, and mood. The chemical structure of serotonin closely resembles that of many hallucinogens. A hallucinogen like LSD can bind onto serotonin receptors, mimicking the actual neurotransmitter, resulting in unnatural stimulation in different areas of the brain. The actual serotonin neurotransmitter is structurally different than the other synaptic messengers of the brain, and meth affects this system in different ways. One way meth use affects the serotonin systems is by reducing the levels of chemical serotonin in the brain. This reduction can produce radical mood changes in people and in animals. When a person has a deficiency in brain serotonin levels, they are more likely to exhibit violent behavior, anxiety, depression, impulsiveness, and could have a propensity towards drug and alcohol abuse. When a person has higher levels of serotonin in the brain, they are less aggressive, mellow, and happier
With the introduction of the drug meth, brain serotonin levels slowly diminish. This reduction in serotonin levels is a result of meth blocking the synthesis and release of chemical serotonin from the synapse. The serotonin system becomes restricted, and the chances of violent behavior and depression increase as the effects of the drug start to wear off. The person's need to keep taking meth far outweighs any moral and financial obligation. The user may commit crimes for drug money, may abandon their family, or may stop paying rent or house payments in order to keep taking meth. An irreversible aspect of meth use is that it does kill certain neurotransmitter synapses, and this is the case with serotonin synapses. Even low level meth use kills serotonin axons. What does this mean for the meth users? For the rest of their lives they are going to be lacking the ability to produce adequate amounts of serotonin. Feelings of depression and guilt could be theirs till they die. The meth user is going to be more inclined towards drug and alcohol abuse. Maybe abuse will be the least of the meth user’s problems. (Karch 2006) The complexity of the ways meth affects neurotransmitters is far beyond the scope of my article. However, there are some facts that are perfectly clear. Meth kills dopamine and serotonin neurotransmitter cells. This is an irreversible consequence since these nerve cells do not grow back with time. Meth short-circuits the user’s brain, is highly addictive, and many of the abuser’s joys in life will slowly vanish as these nerve cells wither and die.
References Karch, S (2006). Drug Abuse Handbook . San Fransico,CA: CRC Press. Covey, H (2006). The Methanphedetamine Crisis . Cambridge, MA: Greenwood Press. Wilson, M (Director). (2006). The Meth Epidemic [TV series episode]. In Frontline . Boston: PBS. Weiton, W (2008). Psychology . Las Vegas,NV: Thomson Watsworth.