Smoking, Health, and Personality

Eysenck argued that the statistical association between smoking and lung cancer did not establish causation. He proposed that personality and constitutional factors—specifically extraversion—predispose individuals both to smoke and to develop cancer, creating a spurious correlation . He presented longitudinal studies claiming psychological characteristics were stronger predictors of heart disease and cancer than smoking behavior, and that psychological treatment could halve death rates . Eysenck saw the cause-and-effect relation between cancer and smoking as an oversimplification, a position he maintained despite overwhelming subsequent evidence to the contrary.

Eysenck's theory held that extraverts have lower cortical arousal and seek stimulation, including nicotine, to achieve optimal arousal levels. This linked his smoking argument to the arousal theory developed in The Biological Basis of Personality . However, the empirical support for this connection was inconsistent from the start. A 1984 study found that among female student nurses, extraversion differentiated smokers from non-smokers, but neuroticism and psychoticism did not add predictive power except through interaction effects . A separate study of 1,529 subjects found no extraversion effect when age was controlled, concluding that apparent extraversion differences were an artifact of younger people both smoking more and scoring higher on extraversion .

A PsycCRITIQUES review by Bernhard Kempler in 1967 was notably critical, observing that the book's main purpose and intended audience were unclear . Kempler noted that while Eysenck's attack on existing smoking-cancer data was 'detailed, incisive,' his exposition of his own alternative hypothesis was 'loosely reasoned, more tolerant of questionable data, and occasionally inconsistent' . The reviewer found the overall effect 'somewhat perplexing.' A Book News annotation on the 2000 reissue similarly described Eysenck as a 'maverick psychologist' whose thesis was 'even more contentious now than in 1965' .

The book was first published in 1965 by Basic Books in New York, running 166 pages . A UK edition was published by Weidenfeld and Nicolson in London the same year . Transaction Publishers reissued the book in 2000 with a new foreword by Stuart Brody . Routledge subsequently published editions in 2017 and 2018 as part of its psychology reissue program . The 2000 Transaction edition includes a foreword in which Brody notes that massive anti-smoking and anti-cholesterol campaigns have had 'little or no demonstrable health benefits' .

Subsequent epidemiological research overwhelmingly contradicted Eysenck's central claim. Tobacco smoking is now established as the single largest preventable cause of cancer worldwide. The personality-cancer hypothesis was never substantiated by large-scale prospective studies with adequate controls for smoking. Even the extraversion-smoking correlation Eysenck relied upon proved inconsistent across populations and partly attributable to age confounding . A 1984 study summarized the literature as 'puzzling' precisely because no single study reported significant effects for both extraversion and anxiety simultaneously, and different populations yielded different results . Eysenck's argument is now viewed as a historical example of motivated reasoning against a public health consensus.

Smoking, Health and Personality was part of a pattern in which Eysenck positioned himself as an iconoclast against medical and psychological orthodoxy. The book's publisher notes he 'spoke the unspeakable, iconoclastically attacking the cherished attribution of millions of deaths to smoking' . This stance aligned with his later controversial positions on race and intelligence, and his association with tobacco industry funding. The book is now studied primarily as a case study in scientific controversy and the limits of individual researchers challenging overwhelming evidence. Its reissue by Routledge reflects ongoing interest in Eysenck's role in twentieth-century psychology debates rather than vindication of his claims.