Relationship of personality and physique to plasma cortisol levels in response to anxiety.

A relationship between physical constitution and temperamental traits has been described from the earliest times. Modem concepts began with the work of Kretschmer (1936) associating types of physique with personality qualities in relation to some psychiatric illnesses. The main problem encountered in these studies has been the difficulty in measuring personality and body-build with satisfactory object-ivity. The history of the work concerning anthropo-morphology and the various classifications suggested have been reviewed by Rees (1960). A useful advance was made by Sheldon (1940) who postulated three physical dimensions-endomorphy, mesomorphy and ectomorphy-and he later reported associations between physique and temperament, with high correlation coefficients found between variation along the physical and psychological dimensions (Sheldon, 1942). But Sheldon's method of somato-typing is basically photographic and does not entirely eliminate a subjective element. In order to improve objectivity of assessment Parnell (1958) modified Sheldon's work and developed his system of phenotyping, using a seven-point scale for each of the similar dimensions of fat, muscularity, and linearity (F, M, L), and this method has been employed in the present study. In a previous report (Bridges and Jones, 1967) it was noted that there have been a number of studies in which physiological variables, such as plasma cortisol levels and urinary catecholamine excretion, have been used as measures of anxiety in various stressful situations, and the results of such work have tended to show considerable variation between subjects, which suggests that the stresses may not always have been adequate to produce measurable anxiety or that there may have been individual differences in responsiveness. In the earlier study we observed medical students taking a viva voce exam-ination which, as it is not merely a contrived situation, is likely to act as a reliable and considerable psychological stress. Therefore it may be assumed that any variation in responsiveness is probably due to individual factors, the nature of which we