Evolutionary Science’s Application to Psychology and Pharmacology

In this essay, the methods by which evolutionary science is applicable to psychology and pharmacology will be discussed. Evolutionary theory informs and guides these fields in research, medical treatment, and other applications. The impact of evolution on psychology cannot be understated, with the Annual Review of Psychology calling it “the second wave of the cognitive revolution.” The field of evolutionary psychology is relatively new, but its room for exploration is vast because it “can be applied to all areas of psychology, new research programs have emerged and will continue to emerge.

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Likewise, the same can be said for evolutionary pharmacology, which is anticipated to be “basic science not only for medicine but also for drug discovery.” Evolutionary theory informs pharmacological research at the molecular level with regard to drug targets and improved methods for combating growing antibiotic resistance among microbial species. Both evolutionary psychology and evolutionary pharmacology are fields with vast potential and have already had a profound impact on their respective fields, as will be discussed.

As has been effectively demonstrated throughout this winter course, evolutionary theory has a substantial impact on the medical issues humans face today. Evolutionary theory has often been applied to clinical sciences, i.e., physicians tailor drug treatment schedules to more effectively reduce drug-resistant HIV pathogens through a process involving “drug cocktails” (multiple antiviral drugs), thus reducing the viral load of HIV-associated pathogens in vivo. There is also useful data in our evolutionary history that reveals when and where aspects of our biological system evolved. This assists us in understanding how certain diseases exploit our biological systems and how to treat them. We often treat these diseases and ailments with medications.

Pharmacology, as defined by the Merriam-Webster Dictionary, is “the science of drugs including their origin, composition, pharmacokinetics, therapeutic use, and toxicology.” Drugs play a fundamental role in medicine, and in this section of the essay, I will discuss the applications of evolutionary theory to pharmacology, specifically drug discovery and design, and its applications to problems such as antibiotic resistance. First, however, I will attempt to briefly describe the nature of evolutionary pharmacology and a few of its applications.

Evolutionary pharmacology, like other evolutionary sciences, is largely based on comparative pharmacology and involves “the study of changes in the action of biologically active substances.” Comparative pharmacological analysis has been carried out to provide numerous insights into what is known as the “antioxidant paradox.” Antioxidants are chemicals that scavenge for reactive oxygen species, such as peroxides and free radicals, that can cause significant damage to cellular structures when in excess. Human biological systems (and many others) have evolved natural defenses against the toxic effects of such reactive oxygen species, which include, but are not limited to, the production of antioxidant enzymes and antioxidants.

Modern-day antioxidant supplementation consists primarily of polyphenolic chemical compounds. However, evolutionary insights into the nature of polyphenolic compounds reveal that their primary function differs from what is currently believed. Despite increasing the levels of polyphenol antioxidants beyond their natural blood concentrations, “plasma antioxidant capacity could not be improved.” This initially suggested that this method, which involves increasing phenolic antioxidant doses, is ineffective in treating the presence of excess ROS in humans. Upon further investigation and experimentation, it was demonstrated that the expression of genes coding for the biosynthesis of polyphenols was “markedly upregulated (6–130 times) under UV-B radiation.”

These conclusions, along with those from several other lines of evidence, suggest that polyphenols primarily act as a filter for UV-B radiation, whereas antioxidant defense is only one of its secondary evolved mechanisms, if any. Likewise, extremely radiation-resistant microbial species were shown to have meager polyphenolic antioxidant activity. This, along with evidence of non-phenolic compounds playing a key role in antioxidant defense systems in radiation-resistant microbial species, suggests that nonphenolic, rather than phenolic, chemical compounds should be considered in the future treatment of excess ROS in vivo. As briefly mentioned in this course, we learned that the “rapid emergence of antibiotic-resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics, which have transformed medicine and saved millions of lives.”

There are several methods of reducing antibiotic resistance (AbR) such as: not using antibiotics to treat viral infections, completing the full course of an antibiotic prescription, and using combinations of drugs to treat infections. However, as the article pointed out, this merely “delays the inevitable.” Evolutionary knowledge provides inspiration for various different and new theoretical approaches to drug design, discovery, and administration.

Evolutionary theory is applied to the development of antivirulence drugs in efforts against AbR. With traditional antibiotics, resistance is often, if not always, beneficial to a pathogen. However, antivirulence drugs seek to change this. When antibiotics inhibit or kill non-resistant strains, resistant strains are robustly selected in a competitor-free environment. Antivirulence drugs aim to change this because they “are not designed to directly harm their targets.” They will have little effect on the pathogen’s fitness in the host, making them “an ‘evolution-proof’ drug that does not impose selection for resistance.”

Despite the inevitability of increased antibiotic-resistant pathogens, “their rise in frequency under the action of drug selection is not inevitable and can even be reversed.” These new antivirulence drugs seek to hijack and control the genetic drift of bacterial populations, ensuring that bacterial strains that have developed mechanisms for antibiotic resistance are selected against. These drugs do this by targeting virulence factors associated with developed resistance mechanisms; virulence factors contribute to the strain’s ability to evade natural human defenses and propagate within.

There are several ways to target virulence, and it is recommended that these be incorporated into further research on dealing with increasing AbR. It is also suggested that “a truly ‘evolution-proof’ combination of virulence factor targets and treatment environment — in which the drug treatment consistently selects against resistance — is possible.”

One fundamental role of pharmacology is that evolutionary theory inspires the biosynthesis of drugs by identifying more effective drug targets. This is an essential aspect in which evolutionary theory informs many promising and developing methods. Drug targeting strategies in fighting antibiotic resistance (AbR) are greatly informed by evolutionary theory. But how do these strategies aim to control the genetic drift of these bacterial populations? This is achieved by targeting the mutational capabilities of bacteria.

Research has found that microbial evolution, a consequence of the many mutations caused by errors in DNA replication, is a natural evolutionary process. Therefore, preventing the evolution of microbes is a “viable strategy to delay the onset of antibiotic resistance.” Because the mutations of resistant strains are typically harmful to other cell functions such as protein folding and stabilization, they often require chaperone proteins (i.e., heat shock proteins) to alleviate the harmful side effects.

Heat shock proteins (HSPs) have been shown to assist microbial evolution by stabilizing proteins, ensuring correct folding and/or refolding. Cowen and his team conducted a “proof-of-concept” study that presents chaperones as a drug target to control bactericide resistance. This is because “The overexpression of chaperones also promotes genetic variation and enzyme evolution in bacteria.” By inhibiting chaperones that ensure the stability of otherwise unstable proteins caused by mutations that promote AbR, bacteria with resistant mutations will be selected against. This technique was tested and implemented more actively in vitro and in mouse models, as “blocking LexA cleavage prevented the evolution of antibiotic resistance in bacteria.” These mechanisms are exceptionally intriguing, and the way they draw upon evolutionary theory is self-evident.

Evolutionary theory provides a range of different drug targets—though these are not permanent or stand-alone solutions—to problems associated with increasing AbR. It aids in drug design, discovery, and administration. Merriam-Webster defines evolutionary psychology as “the study of human cognition and behavior with respect to their evolutionary origins.” Evolutionary psychology seeks to describe relevant mental and psychological traits as a result of natural selection.

Central to evolutionary psychology is the study of psychological adaptations or their mechanisms. This is because “the brain owes its functional organization to a natural, evolutionary process; an evolutionary psychological approach is a logical framework on which to base all psychological theories”. The introduction of evolutionary theory to psychology has provided the ability for new sub-fields, new insights into existing theoretical frameworks, and explanations for human behavior with regard to social psychology.

There are many fields of research being integrated into psychology because of evolutionary theory, one of which is phylogenetics. Phylogenetics is mainly concerned with the relationships of organisms to other organisms according to evolutionary similarities and differences. Explaining mental traits and their phylogenetic origins could provide incredibly insightful and possibly useful applications to modern psychological theories.

Other evolutionary insights into psychology seek to explore what behaviors are indicative of health or sickness. These insights aim to more clearly distinguish between normal and abnormal behavior and understand their implications. The medicinal applications of evolutionary psychology lag behind other evolutionary sciences. However, various lines of research and articles use its approach to address other societal issues. For example, evolutionary psychologist Pat Barclay explores the role and effects of the reputation of power in settings of human conflict in his research.

Evolution informs insights into psychological theories in a variety of ways. For example, consider the regulation of attention. This principle suggests that more of one’s attention is allocated to certain individuals, such as giving less attention to someone newly met in comparison with a close friend. This tendency demonstrates that there is “a default setting that allocates more attention to ingroup members than outgroup members.” Evolutionary science explains this principle. Studies in paleoanthropology demonstrate that our species evolved as group-living, with the group sizes ranging from 25-200 people. This evolution occurred due to the predominance of interactions with ingroup members over those with outgroup members. Interactions with outgroup members contribute little to one’s fitness except in the presence of danger.

This line of reasoning was tested to demonstrate that outgroup faces displaying signs of hostile intent increase one’s attention to that face. This hypothesis was tested in an experiment where faces displaying varying emotional cues were shown on screen. The experiment found that participant recognition of these faces improved when the faces demonstrated emotional cues suggesting anger, especially amongst the faces designated as the outgroup. This experiment is an example of how evolutionary theory can explain theories in fields such as social psychology, providing a better framework for research and testing.

In conclusion, both psychology and pharmacology have many applications of evolutionary theory. These applications provide valuable insights into medicine through the use of evolutionary theory.

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