Impact of Dopamine on Human Behavior

This essay explores the impact of dopamine on human behavior, including its role in regulating the reward circuit in the brain, addiction, and substance abuse. It also discusses how dopamine affects memory, learning, and attraction.

Running head: IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
Impact of dopamine on human behavior
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1IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
Dopamine or 3,4-dihydroxyphenethylamine, is an organic chemical compound which
plays an integral role in the human body and the brain. In the human body, dopamine is
synthesized mainly in the kidneys and in the brain. Dopamine, as a chemical compound, works
like a neurotransmitter. Neurotransmitters are chemicals which are released by the nerve cells or
neurons. The neurotransmitters are transmitted from one nerve cell to another through a number
of dopamine pathways. The brain consists of a number of these distinct dopamine pathways
which would play a major role in determining the motivational components of reward motivated
behavior (Schultz, 2013). For instance, conditioning theory of human behavior states that human
beings are inherently inclined towards rewards and that they are motivated by it. The anticipation
of a reward would increase the level of dopamine present in the brain. As a matter of fact, a
number of drugs and chemical substances are often artificially (and usually illegally) injected
into the human body to boost the levels of dopamine in the body. The following essay attempts
to understand the impact of dopamine on human behavior.
The circuit of the brain which is instrumental in the neurological reinforcement of human
behavior is known as the limbic reward system. This circuit is also known as the dopamine
reward system. The use of any kind of substance, be it alcohol, drugs, marijuana, nicotine,
cocaine and so on, has an impact on the limbic reward system (Ncbi.nlm.nih.gov, 2018). When
an individual consumes such a substance, it triggers the release of dopamine, which as explained
earlier, is a neurotransmitter. Increased levels of the dopamine neurotransmitter in the body
would regulate and increase the sensations of pleasure in the body, especially that of satisfaction
and euphoria (Simington, 2017). In fact, it has also been found that changes in the levels of
dopamine in the body would lead to changes in reward reinforcement, cognition, motivation
levels and motor or movement of the body (Lammel, Lim & Malenka, 2014). An increase of

2IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
dopamine in the body would improve the mood of a person and cause a sense of euphoria. It
would also make a person more agitated and restless, thus regulating body movement or motor
activity of a person as well. However, excessive quantities of dopamine in the brain would result
in aggressiveness, irritability, nervousness or even paranoia. The side effects in that case begin to
resemble that of schizophrenia, since they may cause hallucinations or bizarre thoughts which
are associated with dopamine usage (Howes, McCutcheon & Stone, 2015).
Normal day to day activities like consumption of coffee, eating, drinking or even sexual
intercourse can result in activation of dopamine pathways, increasing the release of dopamine in
the human brain. This results in immediate and temporary feelings of pleasure in the body.
When the level of dopamine in the body subsides, the feeling of euphoria goes down as well. The
process acts like a vicious cycle (Kim & Kyung, 2017). For instance, consumption of coffee,
which has caffeine, works in the same way as the consumption of heroin, although the side
effects are comparatively less. On consumption of coffee, the level of dopamine released in the
body is increased. In this case, the neurotransmitter blocks the reception of adenosine which
makes a person feel alert and active. That is why people tend to use coffee to stay awake or
active. In other words, it boosts the system (Bayer, Lau & Glimcher, 2017). Caffeine also
manipulates the dopamine production system in both animals and human beings so as to make
them feel good. While usage of caffeine is good on a short term basis, it may lead to addiction in
the long run. It is assumed that dopamine is what is responsible for the addiction. Caffeine and
the excess release of dopamine in the body would affect human behavior in adverse manner in
the long run, by altering sleep patterns. While a person may be able to sleep after consumption of
coffee, he or she may still be sleep deprived and suffer from sleep disorders with regular
consumption.

3IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
Dopamine is also known as the molecule of happiness in the human body. When people
consume substances like methamphetamine or cocaine, the dopamine pathways in the brain are
altered which would mean that the neurotransmitter remains in the synaptic gap between neurons
longer. Dopamine has a number of positive impacts on human behavior. Optimum levels of
dopamine in the human body can drive a person towards his goals and provide him with the
sense of pleasure when the goals are achieved (Farhud, Malmir & Khanahmadi, 2014). On the
contrary, feelings of self doubt, lack of enthusiasm or procrastination are associated with low
levels of dopamine in the body. Similarly, people who are more extraverted and outgoing have
higher levels of dopamine in the brain which results in uninhibited personality types. On the
contrary, a person who is meek, subdued and more introverted is likely to have lower dopamine
levels in the body (Kim & Kyung, 2017).
Dopamine, in both humans and animals, has been labeled as the master molecule of
addiction. This is because dopamine is considered to be the chief motivating factor behind
repetitive actions. Since time immemorial, psychologists have suggested and studied how human
behavior can be conditioned or how humans can be taught to act or behave in a certain way.
Psychologists have also suggested that positive and negative reinforcements play a key role in
regulating human behavior (Fiorillo, 2013). In the 1950s, scientists observed that when certain
parts of animals’ brains were stimulated, it led to alterations in their behavior. This was observed
in the case of humans as well. If drugs like amphetamine or cocaine were administered into
human bodies, the sensitivity to feelings of pleasure increased. With repetitive administration,
human beings are likely to choose the electric stimulation of these pleasure centers over normal
day to day activities like eating. When an action which results in pleasure becomes repetitive in

4IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
nature, it is known as positive reinforcement, which is associated with the neurotransmitter,
dopamine (Ncbi.nlm.nih.gov, 2018).
In fact, it has also been found that dopamine is also linked with behavioral tendencies
of avoidance – which are related to the feelings of fear and pain. Dopamine directly affects
the part of the brain called nucleus accumbens, which plays a vital role in triggering the desire
for something specific – food, sexual pleasure and so on – which finally pushes the person to act
towards reaching the goal (Howe et al., 2013). In an experiment, scientists exposed animals to
electric shocks, but also conditioned their behavior by teaching them to escape these shocks. The
level of dopamine in their brains was remotely controlled. It was found that animals with higher
dopamine levels were more effectively able to escape the shocks than animals with lower
dopamine levels. In other words, dopamine in the human body would help people avoid
situations that are potentially painful or unpleasant (Tye et al., 2013). This is one of the major
impacts that dopamine has on human behavior. For instance, the consumption of cannabis or
endocannabinoids fires the release of dopamine in the brain. Marijuana thus stimulates the
release of the neurotransmitter, which can further help people avoid unpleasant situations
(Volkow et al., 2014). This is particularly helps in the treatment of brain disorders like
depression or post traumatic stress disorder. Since dopamine alters human behavior, it reduces
the feelings of desolation and helplessness that such patients encounter. Instead, they are able to
focus on feeling better and improving their situation (Chaudhury et al., 2013).
In fact, the release of dopamine in the body is responsible for common human feelings
and behaviors related to lust, love or attraction. The dopamine pathway in that case is known
as the mesolimbic pathway. Attraction between two individuals involves the pathways of the
brain which control and regulate reward behavior. This explains why the first few days and

5IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
weeks of a new romantic relationship between two individuals can be exhilarating. Dopamine
pushes people to do things that make them feel good – which in this case would involve meeting
loved ones and sexual intercourse (Richard & Berridge, 2013). When there is attraction between
two people, the level of dopamine released increases, along with the secretion of another
hormone known as norepinephrine. This gives a person in love the feeling of being euphoric,
energetic or even giddy. When one is exposed to someone he or she is attracted to, dopamine
triggers the primary pleasure centers of the brain which include caudate nucleus. This results in
human behaviors like blushing, shying away, refusal to acknowledge their feelings and so on.
Similarly, unfavorable behaviors in love, which include erratic behaviors, irrationality or even
jealousy, are also triggered by dopamine levels in the body. Since dopamine has almost complete
dominance over the brain’s reward pathway, it controls both the bad and the good. In other
words, dopamine is responsible for both the good and bad behaviors. Attraction and lust may be
compared to any form of addiction, like cocaine. When someone consumes cocaine, dopamine
signaling in the body is heightened which leads to an ephemeral high. It is similar in the case of
relationships. In due course of time, people get “addicted” to their partners or become
emotionally dependent on them (Robinson & Berridge, 2013). This explains the bitter feelings
and cravings for companionship in case the relationship is terminated or in case of separation.
Dopamine has also been found to affect the human memory as well. The pre frontal
cortex of the brain is in charge of human memory and higher ordered thinking. Secretion of
dopamine can lead to improvements in a person’s memory. However it must be remembered that
the levels of dopamine in the pre frontal cortex is extremely delicate. As a result, even the minute
fluctuations in dopamine levels could alter a person’s ability to remember things. As a direct
consequence, dopamine also affects the ability of an individual to learn or retain information

6IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
acquired (Steinberg et al., 2013). If the levels of dopamine are high during a particular activity (it
is released if a person is interested in the activity concerned), the person is likely to remember
the event for a prolonged period of time and vice versa.
However, it has also been found that dopamine could potentially have adverse
effects on human behavior with repeated stimulation. Dopamine is the neurotransmitter that
is responsible for the human behaviors related to substance abuse and addiction (Volkow &
Morales, 2015). Addiction may be a psychological phenomenon, but at the very core, it is a
biological process which involves the repeated exposure to any biological substance. With
repeated exposure, the substance alters the functioning of the brain’s neurons, which ultimately
results in alterations in the dopamine pathways in the human brain. This process is responsible
for addiction related behaviors like tolerance, cravings, dependence or sensitization (Nutt et al.,
2015). Substance abuse or substance addiction refers to the habitual administration of a
substance, which can have an impact on a person’s mood or states of consciousness. In other
words, a person who is dependent on substance or addicted to it, will continue to crave for the
substance even in its absence. Repeated or chronic use of substance would alter the reward
circuitry in the body, which is a behavioral tendency known as counteradaption. Craving is one
of the most crucial aspects of addiction, and is closely related with dopamine release. The
pleasure and euphoria that is associated with dopamine secretion is responsible for the feelings of
cravings in the absence of the substance which triggers dopamine release (Volkow et al., 2014).
Craving is a human behavior which becomes closely associated with specific memories. In other
words, use of stimulants could condition human behavior in such a manner that any stimuli
(specific locations, paraphernalia, friends who use substances, moods et cetera) which have been
previously paired with the substance would lead to an intense desire or arousal for the substance.

7IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
In fact, dopamine or the reward circuitry of the brain can also be said to be responsible for the
withdrawal symptoms and relapse which are common in patients recovering from substance
addiction.
In conclusion, it can thus be said that dopamine, a neurotransmitter which occurs
naturally in the human body, is one of the most important factors which regulate human
behavior. There are a number of aspects of human behavior, both positive and negative, which
are regulated by the dopamine pathways present in the human brain. When a person consumes
certain substances like cocaine or marijuana, the dopamine pathways in the brain are activated
and higher levels of dopamine are released in the human body. This gives rise to feelings of
euphoria and pleasure. In other words, dopamine as a neurotransmitter regulates the reward
circuit in the brain, resulting in positive and negative reinforcement of behavior. However, as the
discussion above shows, dopamine is not simply concerned with positive behavior. Certain
negative aspects of human behavior like addiction and substance abuse are also associated with
dopamine.

8IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
References:
Bayer, H. M., Lau, B., & Glimcher, P. W. (2017). Statistics of midbrain dopamine neuron spike
trains in the awake primate. Journal of neurophysiology.
Chaudhury, D., Walsh, J. J., Friedman, A. K., Juarez, B., Ku, S. M., Koo, J. W., ... & Nectow, A.
R. (2013). Rapid regulation of depression-related behaviours by control of midbrain
dopamine neurons. Nature, 493(7433), 532.
Farhud, D. D., Malmir, M., & Khanahmadi, M. (2014). Happiness & Health: The Biological
Factors-Systematic Review Article. Iranian Journal of Public Health, 43(11).
Fiorillo, C. D. (2013). Two dimensions of value: dopamine neurons represent reward but not
aversiveness. Science, 341(6145), 546-549.
Howe, M. W., Tierney, P. L., Sandberg, S. G., Phillips, P. E., & Graybiel, A. M. (2013).
Prolonged dopamine signalling in striatum signals proximity and value of distant
rewards. Nature, 500(7464), 575.
Howes, O., McCutcheon, R., & Stone, J. (2015). Glutamate and dopamine in schizophrenia: an
update for the 21st century. Journal of psychopharmacology, 29(2), 97-115.
Kim, H. S., & Kyung, R. (2017). Study of the Neurochemicals Creating Happiness and Positive
Psychology. Bulletin of the American Physical Society, 62.
Lammel, S., Lim, B. K., & Malenka, R. C. (2014). Reward and aversion in a heterogeneous
midbrain dopamine system. Neuropharmacology, 76, 351-359.

9IMPACT OF DOPAMINE ON HUMAN BEHAVIOR
Ncbi.nlm.nih.gov. (2018). Chapter 2—How Stimulants Affect the Brain and Behavior. Retrieved
from https://www.ncbi.nlm.nih.gov/books/NBK64328/
Nutt, D. J., Lingford-Hughes, A., Erritzoe, D., & Stokes, P. R. (2015). The dopamine theory of
addiction: 40 years of highs and lows. Nature Reviews Neuroscience, 16(5), 305.
Richard, J. M., & Berridge, K. C. (2013). Prefrontal cortex modulates desire and dread generated
by nucleus accumbens glutamate disruption. Biological psychiatry, 73(4), 360-370.
Robinson, M. J., & Berridge, K. C. (2013). Instant transformation of learned repulsion into
motivational “wanting”. Current Biology, 23(4), 282-289.
Schultz, W. (2013). Updating dopamine reward signals. Current opinion in neurobiology, 23(2),
229-238.
Simington, M. O. (2017, December). THE WAY YOU MAKE ME FEEL. In Phi Kappa Phi
Forum (Vol. 97, No. 4, pp. 11-11). National Forum: Phi Kappa Phi Journal.
Steinberg, E. E., Keiflin, R., Boivin, J. R., Witten, I. B., Deisseroth, K., & Janak, P. H. (2013). A
causal link between prediction errors, dopamine neurons and learning. Nature
neuroscience, 16(7), 966.
Tye, K. M., Mirzabekov, J. J., Warden, M. R., Ferenczi, E. A., Tsai, H. C., Finkelstein, J., ... &
Gunaydin, L. A. (2013). Dopamine neurons modulate neural encoding and expression of
depression-related behaviour. Nature, 493(7433), 537.
Volkow, N. D., Wang, G. J., Telang, F., Fowler, J. S., Alexoff, D., Logan, J., ... & Tomasi, D.
(2014). Decreased dopamine brain reactivity in marijuana abusers is associated with

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negative emotionality and addiction severity. Proceedings of the National Academy of
Sciences, 111(30), E3149-E3156.
Volkow, N., & Morales, M. (2015). The brain on drugs: from reward to addiction. Cell, 162(4),
712-725.