Senior Seminar in Neural and Behavioral Sciences
Bryn Mawr and Haverford Colleges, Spring, 2002
Session 4: The Genetics of "Psychopathology" and "Personality"
(Readings and Web Links)
To even begin to define personality is complex. There are many different approaches that can be taken when looking at the different perspectives of intelligence (for example: cognitive, behaviorist, humanist). By examining the relationship between personality and psychopathology you can see the relationship between certain personality dimensions and DSM diagnostic categories.
There can be no single gene that can define personality traits. Personality has to be influenced by multiple genes and various factors. For instance, environmental sources of variation in the environment are important. We know people's personality changes depending on what environment and situation they are in. Many people would act differently around a boss than they would act around their friends. Parental upbringing has to have some type of effect on personality.
The genetics of disorders have to do with both heritability and environmentability. To understand the psychopathology of disorders, one usually looks at family, MZ and DZ twins and adopted children. Mental illness can run in families, which shows that genetics plays a role. But genes do not determine everything. For example, sometimes one identical twin develops schizophrenia and the other twin doesn't. Therefore, influences other than genes probably are the reason. Schizophrenia looked at across different cultures could possibly show social and cultural influences. However, as the article on 'The Puzzle of Hypertension of African- Americans' said, pyschological and social stresses are extrememly difficult to measure, especially across cultures. "Identification of a gene associated with a greater susceptibility to a disorder is not equivalent to the cause of the condition." What influences a disorder is not always available for data. There are subtle differences in the brain which can make a big difference when discussing and understanding disorders. Understanding the brain is very complex. Even understanding the hereditary aspects of disorders is complicated. Stresses early in life can cause depression, however I don't see it as the only factor. Stressful life events and genetic factors probably both contribute to depression. But, how should you and do you treat those patients?Psychotherapeutically or pharmacologically? Drugs can have side effects. Should everyone be treated who has been exposed to a traumatic event? After the World Trade Center Attack, many people will not be emotionally the same again. How should we go about treating each individual; with therapy or drugs? What about people who feel they do not need any help?
The relationship between personality and psychopathology is a difficult one to decipher. I would like to say that the two are on a continuum of behavior and that psychopathologies are characterized by extremes in personality. For instance a common personality trait is "being a ham" while an extreme form of this may be classified as a histrionic personality disorder by the DSM. It seems like some behaviors that transcend societal norms transition from personality flaws into psychopathologies. Although I like the idea of putting personality and psychopathology on a continuum, I'm uncertain about this because it is too simplistic and does a disservice to the mentally ill. It creates a problem by implying that the mentally ill could be "normal" if they somehow toned down their eccentricities. To me, it tends to put the focus on individual control or will rather than exploring the multitude of psychological-biological-social factors that can influence one's personality/psychopathology.
There is some influence of genes on personality and psychopathology. Studies on autism have showed that certain alleles (ex: HOXA 1) may be correlated with the disorder. However, it seems that most personality traits and mental illness are probably influenced by an assortment of genes. Also, it is important to acknowledge the role of the environment in all of this. For instance, the diathesis-stress models of depression, schizophrenia, and other psychopathologies are imperative in blending the roles of genes and environment. I'd have to agree with Carey, that once again, it is lemonade.
The exploration of the genetics of psychopathology and personality is extremely important and can immediately benefit society. I never fully grasped the importance of coming up with exact percentages regarding heritability of traits until reading the personal stories in the NIMH readings. These accounts conveyed the intense fear of not knowing if one's 2nd child will also have autism, or if otherwise normal kids will develop uncontrollable schizophrenia in their teens/early twenties. For people with family histories of mental illness, it would be helpful to know how much of a role genes play and whether or not they carry genes that cause certain susceptibilities. This knowledge will help people make an informed decision regarding reproduction, alleviate fears, and prepare them for what is to come.
It seems like certain areas of research have reached a plateau in what they can tell us about heritability and genetics. Family studies and MZ/DZ twin studies can only tell us so much and nothing can really be manipulated leaving countless confounds. Ideally, manipulating one portion of a gene at a time, cloning people, and raising them in the same exact environment (in a lab), and then testing their personality differences would answer my questions, but at this point, that is not legal, ethical or possible.
But then the line gets blurred when you start talking about personality disorders. This type of psychopathology is definetely part of a person's personality and stays with them throughout their lifetime. It is also more resistent to treatment. People in this category seem to have both a psychopathology and personality that is intermixed.
It seems to me that there is more of a genetic predisposition towards psychopathology then towards personality. I get this feeling simply because I have seen all the strong data pointing towards a genetic link with mental illness and have seen it in practice. But from personal experience I don't see a great deal of consistency of personality within the families I know. There is some, but it is not as strong as it is with psychopathology. Also as far as I have seen there has not been a great deal, if any data published on the biological basis for personality whereas every mental disorder has had at least some, if not a great deal published on the neurobiology of it.
I think for our discussion it is better to use at least a more concrete idea of personality such as the reports of other people or the sum of our actions. The two terms are related in that Psychopathology can change our Personalities. As a person develops a disorder, changes may occur in their behavior. This behavior often can reveal the personality, or at least personality-tendencies, of the subject in quantifiable measures making it very useful.
The value of studying genetic behind psychopathology and personality I think is important but it cannot be the whole picture. Certainly in the depression article it was very apparent that the biochemical aspects were critical in our understanding of that disorder. With autism, a critical jump in research was made thanks to genetic research thanks to ingenuity with knockout mice. This was important because it lead researchers to identify a possible gene and variant alleles that could be found in human chromosome 7. Again this does not tell the whole picture but the genetic research is very helpful.
Although it is "helpful" (sorry for the vague term) there is a danger in how far we go with the knowledge we gain. Selecting for happy (as suggested in the fictitious article) kids for instance is not necessarily the best way to use our knowledge. I think that these are definitely dangerous areas where we may be getting involved in things we shouldn't take any part in.
Personality is certainly complicated. It seems plastic in respect to influences in the environment, both chemical and social. When my brother or other friends with attention disorders talk about their experience taking ritalin or aderol they claim it changes their whole personality and don't like taking the drugs because of this despite the postive impact the drugs have on their grades. There also seem to be many examples of where the social environment influences or changes personality, over time, like abuse or even a job that's bearing and stressful, or just in one event like the world trade center bombing, or your baby being born.
Everything we are seems somehow related to genes, not always just what genes we have, but how and when they are expressed. I think most would agree that we have personality traits similar to our parents as much we don't like to admit it. Genetic influence on personality or psychopathology might be useful in someways as a starting off point, but definitely does not tell the whole picture how or why certain genes came to be expressed when and caused what changes that might possibly lead to personality. Basically it is all just lemonade, we have to be content with this mixture, and find other ways to explore treatments and explanations for psychpathology because there is no methodological way to separate the sweet lemony concoction back into its orginal ingredients. There's no rewind button on life why would we try to study it that way?
So to say something specific to personality and psychopathology and thus avoid just recycling last week's posting...the relationship between the two is difficult to understand and subject to societal constructions. With such disorders as depression, anxiety, etc., there seems clearly to be a continuum where being depressed or anxious at times is "normal" but somewhere along the line it is labeled as a "pathology". These cutoffs are necessarily arbitrary and might represent the point where functioning is significantly impaired (or the place where the person becomes significantly unpleasant to be around). With something like depression, with its various symptomology in different people and various personal histories, it seems that the genetic components are likely very complicated, a complication that is, I think, tied to its relation to personality...a period of sadness and disinterest for a generally cheery person might be distressing enough for that person to seek help for clinical depression, whereas the same state might not be far from "normal" for someone with a generally depressive outlook. When these symptoms represent a change from the usual state, they are a pathology; but they might be inherent facets of personality for some people. And since the genetic factors on personality are really complicated, those on psychopathology must be too. But then when you think of a disorder like schizophrenia, a continuum is not as evident...not so many people hallucinate just a little bit, and even if they did that would probably not be considered a "normal" degree of hallucination. That there is no normal here reflects to me the disorder's separation from personality...although colloquially we speak of people as having "schizophrenic personalities", I don't think that's really what happens...it's not just an extreme of a spectrum that has normal at its other end. Of course, when someone is experiencing severe symptoms of schizophrenia, the disorder tends to usurp whatever personality the person had before, so even here psychopathology and personality are related. For disorders like this one which seem more discrete and separate from general personality, I think I would be more likely to buy into a more simple genetic explanation, although the Carey chapter didn't. The stress-diathesis model regarding various psychopathologies is kind of appealing, and makes a good deal of sense for people who had traumatic childhoods, but with depression anyway, there are an awful lot of people who did not. Is their "predetermined threshold" so low that they will develop depression no matter what the circumstances? But in that case, it seems like non-trauma related depression would be more heritable...
I am not sure if there is a specific relationship between psychopathology and personality, other than the fact that they are usually discussed under the domain of psychology instead of biology. Both are like many other traits with genetic diathesis influenced by the environment. Although, personality seems to be harder to pinpoint, because personality is not as easy to quantify. The lack of visibility of heritability may be casued by this vagueness, or simply indicative of the fact that personality is strongly influenced by outside factors.
I think that exploration of genetics in psychopathology and personality is extremely useful. If we don't understand the mechanisms they work with, then how can we claim to understand them at all? If we can pinpoint the genetics of these things we can deduce evolutionary clues from this information as to why they developed the way they did in the first place. Also, it is useful to keep in mind that we are still evolving.
Current observation does not provide real genetic diathesis for personality. The evidence for psychopathology is somewhat more solid, but also admits the influence of environment in the biological diathesis/stress models of disorder development. I found the MZ/DZ and adoption studies pretty compelling evidence for the heritability of certain disorders. Such studies, though, involving the different hypertension rates of blacks across the world detracted from the influence of genetics. It is clear that some traits are more heavily influenced by the environment than others. However, that study failed to show the genetic closeness of the different groups of blacks studied. There are many different ethnic groups in Africa itself, and this detail cannot be overlooked.
However, I also think that making distinction between personality and psychopathology is important in scientific studies because I feel that the genetic studies of psychopathology is far more helpful than those of personality. I do not think that genetic studies on personality is very useful since the environmental factors, which occurs by chance, can alter one's personality throughout their life. As long as the resulting personality does not prevent the person from living independently, there is nothing serious to worry about - at least, the person does not require medical attention. However, in case of psychopathology, such as autism or depression, the victim cannot live by himself. If genetic studies can discover the critical genes and ways to prevent such difficulties in one's life, the genetics of psychopathology will be very valuable. Of course, like personalities, psychopathology also depends on the environmental factors, so the genetics alone would not prevent every case of autism or depression. However, the studies may able to prevent some cases at least.
There are more reasons for whey I do not see importance in personality studies. Like in the fiction, maybe parents will be able to choose the personality of their children in the future. However, everyone already has different personality, and hence, the personality that may appear attractive to the parents may not be pleasing to others. Some people have personality that allows them to see positive characteristics in often neglected people (because of their pessimim or bad temper or whatever) and feel affections toward those socially unaccepted ones. Besides, personality is very complicated - it is not just the matter of being happy or sad, and genetic studies probably fails to come up with generalization of personality traits.
Althogh I have mentioned that personality development depends on environmental factors, too, genetic factors also may influence how someone's personality development is affected by environmental factors. Two people could grow up in the same environment and still could have very different personalities. I suspect that the difference in suceptibility to environmentally caused change in the brain structure (or the neurochemical systems) arises from the difference in the genetic make-up of the two people.
Now, this is unrelated to what I have discussed so far, but as I was reading "The Neurobiology of Depression", I came up with a question. The rats study showed that maternally deprived rats displayed signs of depression as adults. If these rats were given antidepressants as neonates (while being separated from their mothers), would they still show increased level of CRF concentrations in several areas of the brain in their adulthood?
Next. I think the conversation went relatively well today, and though I'm sorry I missed responding to this earlier, I'm glad I got a chance to refine some of my beliefs through listening to the discussion.
I wanted to put up this link to a Jungian Personality test. Though there's a stigma that follows his name, and people don't find him so scientific. I feel that the expression of the 'science' (the gene influence of personality) is manifest in individuals in ways that are still hard to quantify and calculate. I think that this test and what it looks at are the key to personality. I like the distinction that we made today between Identity and Personality. I Do believe that personality is more stable and that they are more like things in How we interact with situations, not just What we do. I think the introvert/extrovert example is a very good one.
Here's the link. Though it doesn't seem so official it does have over 50 questions it calculates and does it in a relatively sophisticated way. It's quite similar to the 'official' tests. Though those are more fun to do.
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Personally I'd be interested in finding out what everyone gets as an answer and if they're pleased with it. You don't have to share them, necessarily but it could be interesting. I'm an INTP. And I think that's pretty close to who I am. Not only that, but I took this in Highschool for a class (the official version) and I had the same thing, even back then. And I feel like I have changed as a person since then. At least Identity wise, but also on some general outlooks on life. Yet I still get this same score. That means a lot to me, and I feel that it is in concordance with my personal views on the topic.
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