In the 1980's and 90's, together with Ronald Grossarth-Maticek, Hans Eysenck researched and wrote extensively about the relationship between personality and disease. In sum, they reported that cancer and other fatal diseases were caused primarily by personality. For example, they questioned whether smoking caused lung cancer or whether it was personality traits that led to the smoking that caused the lung cancer and they found huge effect sizes that are never seen in biomedical research. Even though serious criticisms of their work were published in the 90's, their work was never investigated. In his review paper, Dr. Anthony Pelosi has called this “one of the worst scientific scandals of all time.”
Why it matters
"This programme of flawed research continues to influence the literature to the present day and remains highly cited." Their research continues to be reviewed, cited, and included in meta-analyses. A 2019 article in the Annual Review of Psychology states that: ‘the strongest conclusion derived from decades of research on stressors and cancer is that stressful events may be associated with decreased cancer survival but are probably not associated with disease incidence (Chida et al., 2008)."
They identified four types of personalities: "the cancer-prone type (characterised by ‘passivity in the face of stressful stimulation from the outside’); an ischaemic heart-disease-prone personality (‘inability to leave an unsatisfactory situation [which] constantly increases their anger and hostility’); a mixed type; and a healthy autonomous personality."
Over many studies, they compared the incidence of death from cancer and heart disease to the personality types. Their findings showed that "the all-cause mortalities for treated versus untreated subjects in their individual psychotherapy and group therapy trials were 15 per cent [for treated] versus 62 per cent [for untreated] over 13 years [cancer] and 20 per cent [treated] versus 76 per cent [untreated] over 7 years."
The most astonishing series of findings ever to be published in the scientific literature
"This collaboration led to what must be the most astonishing series of findings ever to be published in the scientific literature. Across the decade-long Yugoslav and first two Heidelberg cohort studies involving 3235 people, 38.5 per cent of the cancer-prone subjects died of cancer compared with only 0.3 per cent of those with the healthy personality. The resultant relative risk of 121 is perhaps the highest ever identified in non-infectious disease epidemiology (except for certain very rare occupational hazards and some of these authors’ previous and subsequent results)." "Such results are otherwise unheard of in the entire history of medical science."
Dr. Pelosi concludes that "there is a complicated and multi-layered scandal surrounding Hans Eysenck’s work on fatal diseases. In my opinion, it is one of the worst scandals in the history of science, not least because the Heidelberg results have sat in the peer-reviewed literature for nearly three decades while dreadful and detailed allegations have remained uninvestigated. In the meantime, these widely cited studies have had direct and indirect influences on some people’s smoking and lifestyle choices. This means that for an unknown and unknowable number of individual men and women, this programme of research has been a contributory factor in premature illness and death."
Dr. Pelosi's paper was published in the Journal of Health Psychology and both Dr. Pelosi and Dr. David F Marks, the editor of the Journal of Health Psychology, have called for a correction or retraction of Hans Eysenck's papers using questionable data sets or making false claims.
References:
Marks, D. F. (2019). The Hans Eysenck affair: Time to correct the scientific record. Journal of Health Psychology. https://doi.org/10.1177/1359105318820931
Pelosi, A. J. (2019). Personality and fatal diseases: Revisiting a scientific scandal. Journal of Health Psychology. https://doi.org/10.1177/1359105318822045
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