Institute of Genetics, Hraunteig 16, Reykjavik, Iceland.
Correspondence: E-mail: jonlk{at}interx.net
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ABSTRACT |
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Aims To test the relationship between academic success and the incidence of psychotic disorders.
Method The unusually complete demographic and scholastic records available in Iceland were used to locate academically accomplished individuals and assess the probability of previously identified patients with mental disorders and their relatives being among such groups.
Results Close relatives of successful students showed increased risks of psychosis. Individuals who subsequently developed psychosis and relatives of people with psychosis excelled in school performance, particularly in mathematics.
Conclusions The study supports the hypothesis that stimulation associated with psychotic tendencies enhances performance in academic settings.
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INTRODUCTION |
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METHOD |
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The investigation was then expanded to include assessment of the academic success of individuals who later developed psychosis and first-degree relatives of patients, again comparing them with the population at large. The records of Icelandic university preparatory schools have been published annually and are available for inspection at the National Library in Reykjavik. They include the names and birth dates of all graduates and the actual grade point scores achieved in each subject by every individual in the final examinations at age 20 years. During the first two intervals, comprising the graduation years 18711930, there was just one gymnasium type educational institution in Iceland, located in Reykjavik, in which all students followed the same curriculum. In the last period, 19311960, a second similar school operated in Akureyri in north Iceland. The parents, full siblings and children of the graduating students, also born in the interval 18511940, have been identified with records at the National Archives.
For an initial exploration, the top graduates each year, born 18511910, were selected, on the basis of the highest grade point average achieved at age 20 years. The two top graduates from the single school were selected for those born 18511910, and for those born 19111940 the top male graduate from each of the two schools was chosen. Thus, there were in this survey 180 index scholars, approximately 0.1% of the total population of 171 000; all were male. These individuals and their relatives were then evaluated for rates of ever having been admitted to the mental hospital, comparing their risk of hospital-treated psychosis with the figure of just under 1% already established for the general population. The expected numbers of such patients among the graduates and their relatives were computed separately for each generation according to the basic data (Karlsson, 1988) and then added together. Since it was only in the third study period that young women started attending advanced schools in significant numbers, a similar longitudinal study of women was not feasible.
A second investigation was limited to the generation born 19111940, selecting for assessment of mental disease the first-degree relatives of the three highest graduates in terms of overall grades each year, separately for each gender, at Reykjavik College in the period 19311960. The school had by then been divided into two sections, humanities and mathematics, requiring these populations to be dealt with separately. All students in a given class followed the same curriculum and took the same tests. Most of the women chose the humanities section.
A third comparison was based on risk of illness among those who achieved the highest grades on the written final mathematics test in the mathematics and science section of Reykjavik College during the years 19311960. This examination required solutions of difficult problems in algebra, geometry, analytical geometry, trigonometry and calculus. All male students achieving a score of 90% or higher were included as index cases in the first study, as well as the four highest-scoring students in years when all marks fell below 90%. Since the same problems cannot be used too frequently in the examinations, there is bound to be some variation in the difficulty of the test from year to year. A parallel second study has been made of all women achieving a grade of at least 40% on the written final. Only one woman scored above 90% in mathematics.
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RESULTS |
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The next survey (Table 2) centred around the three highest-scoring individuals (both male and female) in terms of average grades every year in either section of Reykjavik College graduating in the period 19311960. This equates to 90 persons in each group. However, since few female students chose the mathematics curriculum, that group is based on all 83 female graduates in that category in the same period. Five of the top-scoring males as well as two high-scoring females were later hospitalised with schizophrenia. The table includes parents and full siblings of the high performers, the expected rates of hospitalisation again being about 1% among these first-degree relatives. An increased risk over the expected value is seen only among relatives of those who chose the mathematics programme. In all the groups there were 11 people with schizophrenia and 13 with affective disorders.
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The third comparison, summarised in Table 3, first evaluates the risk of psychosis in index cases and among close relatives of 90 male students who distinguished themselves as highest performers on the mathematics test at Reykjavik College in the period 19311960. Instead of the expected 4.3 instances of psychosis in the whole group there were 11 instances: 4 of schizophrenia and 7 of affective disorder. An evaluation of psychosis in families of 52 female graduates scoring at least 40% on the mathematics test revealed a similar pattern. Here two of the index individuals were diagnosed as having schizophrenia, and 3 of their 122 siblings as well as 3 of their 93 parents were treated for psychosis (2 schizophrenia and 4 affective disorder).
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All the patients and their relatives surveyed in this study were identified in the earlier research on family risks of psychosis (Karlsson, 1988) without any intention at that time to investigate their academic performance. These people were seen only as potential carriers of psychosis genes.
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DISCUSSION |
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Many years ago the claim was made that relatives of patients with psychosis exhibited a thought disorder on the Lovibond Object Sorting psychological test (McConaghy, 1959). This report aroused a great deal of attention, and several investigators attempted to replicate its findings. The conclusion was that differences did indeed exist between the responses of control groups and those of patients relatives, although less definitively than suggested by the original findings. When subsequently the principal author discovered that thought disordered college students were often the high-performing members of their classes, the suggestion was made that the deviant responses should be designated allusive thinking, to avoid the negative implication of the former terminology (McConaghy & Clancy, 1968). After that, interest in the subject dwindled.
More recently, other investigators have attempted to identify early signs of mental deviation in relatives of patients, suggesting that preventive treatment might be in order to intercept psychosis before the appearance of overt symptoms (Tsuang et al, 2000). Another research study conducted in Finland demonstrated that top male performers in middle school were at increased risk of subsequent development of psychotic illness (Isohanni et al, 1999). That study did not focus on the families of psychiatric patients.
Present data
The study reported here assesses the effect of psychosis factors on mental
performance in affected families, using the unique opportunity existing in
Iceland for demographic research. The investigation is aimed primarily at
elucidation of the personality characteristics of relatives of people with
psychotic disorders. The findings consistently indicate that healthy members
of the families of people with psychosis often exhibit an advantage in
academic performance.
The data in Table 1 leave little doubt that the altered levels of brain activity seemingly associated with risk of psychosis can lead to superior performance in academic settings. The top performers tend to be relatives of patients if they are not themselves psychosis-prone. Most of the individuals surveyed here lived in the period before the educational emphasis shifted to mathematics and science, but even in college subjects covered a century ago, an increase in psychosis was apparent among the gifted students.
Table 2 narrows down the fields in which individuals with high levels of brain arousal predominate. The risk of psychosis does not seem to appear in groups preparing for careers in languages, literature and jurisprudence, for example, but is more definitive in those headed for science or mathematics. High-performing women show evidence of being at risk of psychosis only when they seek careers requiring scientific skills.
In Table 3 high risks can be demonstrated in both men and women when the focus is specifically on mathematical reasoning. Men achieving grades of at least 90% or women with scores over 40% show elevated rates of psychosis in both the index cases and their relatives. These individuals were preparing for careers in mathematics, physics, chemistry, astronomy, engineering, architecture and medicine. The evidence reported in this paper supports the hypothesis that the elevated levels of mental stimulation encountered in families with psychosis may enhance creative forms of thinking.
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Clinical Implications and Limitations |
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LIMITATIONS
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REFERENCES |
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Huxley, J., Mayr, E., Osmond, H., et al (1964) Schizophrenia as a genetic morphism. Nature, 204, 220 221.
Isohanni, I., Jarvelin, M.-R., Jones, P., et al (1999) Can excellent school performance be a precursor of schizophrenia? Acta Psychiatrica Scandinavica, 100, 17 26.[Medline]
Karlsson, J. L. (1974) Inheritance of schizophrenia. Acta Psychiatrica Scandinavica Supplementum, 247, 1 116.[Medline]
Karlsson, J. L. (1988) Partly dominant transmission of schizophrenia in Iceland. British Journal of Psychiatry, 152, 324 329.[Abstract]
Lange-Eichbaum, W. (1931) The Problem of Genius. London: Kegan Paul.
McConaghy, N. (1959) The use of an object sorting test in elucidating the hereditary factor in schizophrenia. Journal of Neurology, Neurosurgery and Psychiatry, 22, 243 246.
McConaghy, N. & Clancy, M. (1968) Familial relationship of allusive thinking in university students and their parents. British Journal of Psychiatry, 114, 1079 1089.[Medline]
Tsuang, M. T., Stone, W. S. & Faraone, S. V.
(2000) Toward reformulating the diagnosis of schizophrenia.
American Journal of Psychiatry,
157, 1041
1050.
Received for publication March 10, 2003. Revision received November 3, 2003. Accepted for publication December 2, 2003.
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