Although numerous instances of the surprising efficacy of placebos in a wide variety of conditions have been reported lately, little has yet been done towards providing an explanation of the occurrence of placebo reactions in terms of psychology. In what follows, the main findings concerning placebos will first be described, and then an attempt made to relate them to psychological theory. Even if this attempt is premature, it may succeed in showing the need for further work and in suggesting what directions this might take.

No abstract

While it is usual among psychiatrists to express dissatisfaction with psychiatric classification and its problems it is by no means unusual for their psychological colleagues to advocate factor analysis as an effective technique for resolving such problems. For example, Burt (1954) describes factor analysis as “essentially a statistical device for securing the best available scheme of classification”. Yet the problems and the device tend to remain apart, the former becoming intensified, the latter undergoing continued improvements. Twenty-five years ago T. V. Moore (1930) demonstrated that the application of factor analysis to the study of psychiatric disorders was feasible, and more recent work, especially that of Eysenck (e.g. 1947) has impressively shown its fruitfulness. That some clinicians remain sceptical of the claims made for these techniques is, in part, due to the infrequency with which factorial studies bearing on psychiatry have been pursued far enough for their implications to be tested and the findings integrated with those established by other scientific methods. This deficiency may be attributable to the fact that large scale programme research (Eysenck, 1953) is an almost essential condition, if this is to be achieved.

In a previous paper one of us (4) has elaborated a theory relating drug action to personality. According to this theory, depressant drugs increase cortical inhibition (Pavlov) or reactive inhibition (Hull), thus producing an extraverting effect on personality, while stimulant drugs decrease inhibition and produce an introverting effect in behaviour. It was also suggested in this paper that a direct proof of the hypothesis might be obtained by making predictions regard ing the effects of stimulant and depressant drugs on a variety of experimental laboratory situations connected with the general theory of inhibition and excitation.