The concept that nurture has a direct affect on the process of development was first conceived in the 1 ass’s by John Locke, which this was then contested in 1 869 by a man named Francis Gallon who believed that nature alone influenced the process of development. The current consensus within the scientific community is that there is a mixture of both genetic and environmental factors that contribute to mental illness.
The real controversy lies with which Of the two are more prominent in an individuals developmental process and at what point the two intertwine. It is without question that DNA is the building blocks of any human being, recent studies have found that your genetic makeup has a significant impact on how a person responds to stress, which can make certain people susceptible to mental illness, most notably depression. (Syrian Seen, 2011) It is believed that your DNA allows for a range of possible characteristics and tendencies that is then determined by your environment and daily activities.
This last point of course leads to the heart of the controversy between genetic predisposition and environmental triggers, and which is more prominent. A duty released by Lively in 1993 is a perfect example of the attempt to link genetic predisposition strongly to mental illness and found that Narcissistic Personality Disorder had a 64% heritability rate. This study however was widely criticized as to having no consistency with its chosen participants and also failed to mention if any of the participants or their parents had a personality disorder.
Due to these external variables, it was believed that the margin of error was too significant for the studies findings to hold any real merit in presenting a strong link between genetic predisposition and NYPD in reticular. An individuals environment is known to have substantial effects on a persons characteristics and behavior. Aggression and anti-social behavior is one such trait that is used in the argument of nature vs. nurture. The Genetic- developmental theory, although supportive of genes having a direct effect of producing aggression as a trait also states that environmental factors result in being the deciding factor.
An adoption study in Denmark found that siblings, adopted to separate homes had a 12. 9% concordance rate of petty crime or property offenses, showing that an individuals hereditary genetic makeup can increase the risk of some anti-social behavior, but also that the environment has a key role to play. (Medicine, 1984) In recent times there have been five major studies based around adoption and genetic susceptibility to anti-social behavior, criminality and psychopaths. None of these studies found significant evidence in support of genetic influences on violent crime.
However, there was some evidence to suggest that there was a genetic component for petty crime and property offenses. (Crower, Catered, 1972) (Schlesinger, 1 977) (Bowman, 1 978) (Median, 1984) Most interestingly, culture also has a significant effect on mental illness. AAA number of studies undertaken by the World Health Organization showed that schizophrenia and its symptoms differ from culture to culture. In the West, patients suffering from schizophrenia presented more depressive symptoms than their counter-parts in that of non-Western developing countries, who’s symptoms focused more on frequent visual and auditory hallucinations.
This highlighted that mental illness, schizophrenia as an example, was not merely down to genetics alone and that an individuals environment can have a large impact. In conclusion, one of the most popular theories behind the combination of emetics and environment, known as the “two-hit” hypothesis Of psychiatric disorders may be the answer. This of course is supportive of the biophysically model which encompasses biological, psychological and social factors that play a part in mental illness. Studies based upon schizophrenia in particular support the ‘two-hit” hypothesis.
It has been shown that the likes of Schizophrenia can be caused by abnormal development in the early stages of life (Marlene S, Weinberg DRY, 2000). There is evidence that supports this in presenting abnormalities in the brain before psychiatric symptoms occur. Fish B, Marcus J, Hans SSL_, Reproach JOG, Purdue S, 1992) (Done D], crow T], Johnston CE, sacker A, 1994) Although these genetic attributes have been documented, there are many individuals who have these genetic abnormalities but do not go on to develop schizophrenia.
This leads to the “two-hit” hypothesis, that genetic predisposition or vulnerability sets the stage for mental illness but that an environmental trigger in adolescence or early adulthood leads to the onset of such.