In 1978 behavioral scientist Han Brunner interviewed a patient at a Nijmegen hospital in the Netherlands whom was concerned about the extremely aggressive and violent behavior of the males in her family. This family had produce five generation of men that were attempted murders and rapists tracing back a hundred years to 1870. [2] Since it was only men in this family that exhibited these antisocial and psychopathic tendencies, Brunner theorized that it was most likely an X-linked genetic mutation as the woman in the family have two X chromosomes that helps negate the faulty DNA. [1] Through linkage analysis of the families DNA Dr. Brunner team had discovered the specific gene in fact existed on the short arm of the X chromosome. The mutated gene produced an inactive form of monoamine oxidase A that normally would help in breaking down neurotransmitters in the brain. [1] This can explain why antisocial behaviors in males is much more prevalent than in females. [8][9][10] The mutation present in the Brunner studies are extremely rare as this is the only known case of a completely non-functioning MAOA. [2] However, this discovery had lead to the identification of two other much more common alleles coding for this particular gene. These two alleles are MAOA-H (high-activity MAOA) and MAOA-L (low-activity MAOA). [2] There is a clear correlation between physiological and chemical changes of the brain associated with males whom have the low activity MAOA gene. Since men with the MAOA-L alleles brain is bathed in excess dopamine and serotonin from birth the brain adapts by becoming less sensitive to these neurotransmitters thus decreasing activity in key areas of the brain that coordinate aggressiveness and abridging capacity... ... middle of paper ... ...ychopath Inside: A Neuroscientist's Personal Journey into the Dark Side of the Brain. Penguin. [7] Klug, W., Cummings, M., Spencer, C., Palladino M. (2012) Concepts of Genetics: Tenth Edition. Pearson's Education, Inc. [8] American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised. Washington, DC, American Psychiatric Association, 1987. [9] Jim Fallon: Exploring the mind of a killer (2009) Ted: Ideas Worth Spreading http://www.ted.com/talks/jim_fallon_exploring_the_mind_of_a_killer.html [10] James Fallon: Confessions of a Pro-Social Psychopath. (June 2011) World Science Festival http://worldsciencefestival.com/videos/moth_confessions_of_a_pro_social_psychopath [11] Blair, R. J. R. (2007). The amygdala and ventromedial prefrontal cortex in morality and psychopathy. Trends in cognitive sciences, 11(9), 387-392.
Brunner and his colleagues, and upon the discovery of a particular genetic defect in male members of a large Dutch family. In this large Dutch kindred, Brunner et al. (1993) identified a novel form of X-linked nondysmorphic mild mental retardation, and he found that all of the male family members with this defect reacted aggressively when angry, fearful, and frustrated. All the affected males in the family showed characteristic abnormal behavior, in particular aggressive, and sometimes violent behavior. These males in the family displayed mild impairment of cognitive functions and some types of abnormal impulsive behavior which includes arson, attempted rape, and exhibitionism. Even attempted suicide was reported in a single case. The defect discovered was later found to be a mutation in the gene that codes for monoamine oxidase A (MAOA gene). Brunner showed that in the affected males there was a mutation in the gene for the enzyme monoamine oxidase A (MAOA). The enzyme deactivates the hormones and neurotransmitters epinephrine and norepinephrine, more commonly known as noradrenaline and adrenaline. At this time, Brunner said that an "MAO-A deficiency is associated with a recognizable behavioral phenotype that included disturbed regulation of impulsive aggression. The transmission pattern of Brunner syndrome in the families reported was consistent with X-linked recessive inheritance. A man with Brunner syndrome is what expert psychiatrists refer to as “a bad guy.”
American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. Arlington, VA: American Psychiatric Publishing.
-Reilly Philip. Is It In Your Genes. Cold Spring Harbor Laboratory Press. 2004: 223-228. Print
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.
Some factors that are explored in studies involves the genetics in a person, how parents treat their children, influences peers have and the situations that a person may experience throughout their childhood and adult life. There is a possible connection between the feelings of anxiety, aggression and fear with a genetic makeup in a person’s body (Huff, 2004). Research has even shown that if an individual was abuse, whether physical or verbally they are at risk for developing a personality disorder as well (Huff, 2004). Another interesting study conducted by Robert Krueger, PhD, exploring the influences that can contribute to the development of a personality disorder, looks at studying personality traits within identical twins who did not grow up together. In the study, it appeared that genetics contributed more to a person personality trait then the environment they were in. Krueger opinion was that “The predominant reason normal and abnormal personality are linked to each other is because they are linked to the same underlying genetic mechanisms” (Huff,
Lewis, Ricki, (2014), Human Genetics, 11th Edition, Chapter 15 Changing Allele Frequencies, pp 293. [VitalSource Bookshelf Online]. Retrieved from
A complex and relatively new field of study, behavioral genetics is particularly interesting because is sheds light on the inner workings of a favorite subject: ourselves. Human behavioral genetics is broadly defined as the examination and characterization of genes as a basis for human behavior. The link between genetics and behavior was first recognized by Sir Francis Galton, a 19th century scientist and cousin of the very famous Charles Darwin, who studied the heritability of mental abilities of close relatives and family members (Stigler, 2010). Since then, genetics has been linked to many more behavioral phenotypes from eating and mating activities to substance abuse, social attitudes, violence and mental abilities. Geneticists are able to study this by analyzing parallels in physical and behavioral characteristics of families and populations (Rothstein, 2005). However, as with many other new scientific fields, the study of behavioral genetics and its implications has been the subject of increasing scrutiny and co...
American Psychiatric Association. (2000). Diagnostic and Statistical Manual of Mental Disorders: Fourth Edition. Arlington : American Psychiatric Association.
To think how far we have come with medicine and technology is astounding. Looking into the biological model of abnormalities we learn that the focus is to connect a medical prospective to the variations in abnormal behavior. The text uses the case of Philip Berman, a person who exhibits a wide range of emotion when triggered with certain topics. In this case researchers are looking to find a glitch between his body chemistry and his behavior. The question here is: Can there be a connection between imperfect organisms within the body which in turn display abnormal behavior? We learn from the text that the brain has many parts that are designed to specific duties. If one of the nerves or cells is faulty, can it somehow be tied to the way a person acts? The answer is yes. We know that abnormal behavior is not just that of a mental disorder, and we know that certain chromosomal disorders have been proven to cause abnormalities within the human body. In Philip’s case, it is not necessarily a behavior that we know could be caused by a glitch in the system. We learned many facts about his life that can play a role in the way he carries himself. If we were looking into his genetic inheritance we might ask questions like the genetic makeup of the family history (i.e. has there been a history of mental disorder in the family?). Was Philip used to being an only child for so
...R (2005). Evidence for substantial genetic risk for psychopathy in 7-year-olds. Journal of Child Psychology and Psychiatry. 46(6), 592-597
...chiatric Association. (2012). “Diagnostic and statistical manual of mental disorders” (4th Ed.). Washington, DC: Author.
Since the gene for HD is dominant, there is a 50% chance of a sufferer's
6. Joseph, Jay. “Chapter 8: Is Crime in the Genes? A Critical Review of Twin and Adoption Studies of Criminal and Antisocial Behavior.” The Gene Illusion: Genetic Research in Psychiatry and Psychology under the Microscope, Algora Pub., 2004, pp. 278–279.
Neurotransmitters are chemicals in the brain and body that help transmit electric signals from one neuron to other neurons in the body. These neurotransmitters are responsible for the activation of behavioral patterns and tendencies in specific areas of the brain. When a neuron releases the neurotransmitter chemicals, healthy synapse are needed to pass the electric message across the gaps correctly. All of this is important in an individual’s criminal behavior because the transportation of neurotransmitters like dopamine and serotine control a person’s emotions and therefore their behavior. “Dopamine is a neurotransmitter in the brain that is associated with pleasure and is also one of the neurotransmitters that is chiefly associated with aggression.” (Jones, C. M.). An individual usually experiences high levels of dopamine before and after an altercation and it can cause an individual not to recognize the lasting angry expression they have on their face. Also, “Serotonin is a neurotransmitter that is key in information processing and most consistently linked to criminal behavior in its deficiency; low levels are linked to depression and other mental illnesses” (Schram, P. J., & Tibbetts). People with low levels of serotonin have trouble communicating in everyday life and this has a strong connection with criminality because people that
What we were interested in is to gauge if the presence of the Psychopathic trait in individuals coincided with similar levels of the other two traits. To prove that the other two traits can be used to predict psychopathy, we needed at least correlation in any or both of the other traits and the absence of a high negative correlation with any of the traits. A measures of between 0 and 0.3 signify a low correlation, while figures those between 0.3 and 0.5 signify mid correlation. A figure between 0.5 and 1 indicates a high correlation (Andale, 2012). The –ve or +ve sign before the figure indicates whether it is a negative correlation or positive correlation respectively.