Theories of symbolic logic are used in an attempt to clarify the medico-psychological concept of disease. It is argued that the class concept of diseased persons has as its extension the universal class of patients, and as its intension the attribute concept of patienthood (or disease in general). It is proposed that the diagnosis of patienthood has as its sufficient and necessary condition the experience of therapeutic concern by a person for himself and/or the arousal of therapeutic concern for him in his social environment. The experience of therapeutic concern has as its necessary condition, and also as its specific psychological cause, the observation of clinical symptoms and/or other pathological manifestations. The general domain of patients and its various subdivisions are empirical classes which are logically inexact—that is, contain neutral members in the form of dubious patients—and are polythetically characterized—that is, by a loose cluster of pathological attributes of which only a substantial proportion need be exhibited by a class member. The division of the domain of patients (and therefore the classification of patients) is commonly achieved by the addition to the intension of the domain of pathological attributes. These must, of course, be attributes which are not universally or predominantly shared by the domain members. Endopathological and exopathological abnormalities have proved themselves as the most useful classifying criteria. Their addition to the intension of the domain of patients separates particular classes from the rest of the domain. The intensions of these classes correspond to particular diseases, and list all the relevant clinical, endopathological, and exopathological data, if available. When a particular endopathological abnormality is by definition established as the specific cause of its clinical symptoms, then the intension in question corresponds to an aetiologically homogeneous disease entity.

The alpha attenuation response (AAR) and its habituation rate during the course of 60 serially presented paired flash stimuli was measured in a small but homogeneous group of male identical and fraternal twins, all within the age range 19 to 40 years. Comparison of the intraclass correlation coefficients for each of the recorded AAR parameters between the two twin series and a constructed series of genetically unrelated individuals indicated that individual differences in the variables measured were significantly influenced by heredity. The findings are discussed in relation to previously reported studies of the genetic aspects of the normal spontaneous EEG.

Salivary secretion was measured in 34 depressed inpatients who were also assessed clinically and psychometrically. Thirty-one of the patients were reassessed two weeks after a course of ECT. Before ECT, diminished salivation was associated with retardation and gastrointestinal somatic symptoms. Overall, the patients' salivary secretion did not change after ECT. More detailed analysis showed that the salivary secretion of the more retarded patients was low before ECT and increased subsequently, whereas that of the least retarded patients was high before ECT and diminished subsequently. It is suggested that the relationship between retardation and salivation may explain some of the divergent results of previous studies.

At least for heuristic purposes, certain operationally definable concepts of conditioning theory can serve as a framework for research on ‘drug dependence’ both in man and in animals: primary and secondary pharmacological reinforcement, either of which may be direct (‘psychic’) or indirect (‘physical’); and social reinforcement (‘cultural’).

A new method for the measurement of alienation is proposed. It is based upon the conceptual distance between people. For each subject, the observed distances between all possible pairs of elements were calculated and compared with the expected distance between two elements drawn at random. The ratios derived in this way were used to examine intra-self alienation and actual self isolation. The obsessional patient is self alienated and isolated. The normal control subject is self and socially integrated.

The general relationship between alcohol and crime is reviewed, and five central methodological problems are identified relevant to prison population ‘alcoholism prevalence surveys’ as a prelude to a report of an investigation of 500 recidivist prisoners. The prevalence rate is shown to be highly dependent on the particular definition of ‘alcoholism’ which is employed. Long-term and short-term prisoner subgroups are compared, and similarities with a population of non-prisoner homeless men discussed. A ‘dependence score’ derived from an operant conditioning model of alcoholism correlates significantly with various measures of social instability.

Using statistical methods, the hypothesis that suicide occurs either at the beginning or at the end of a spell of treatment is shown to fit the available data.

A one-day census was made (from the Camberwell Register) of children excluded from education in school, children in ESN schools with IQs of 49 or below, and pre-school children suspected of being severely retarded. Their service placements were again recorded 26 months later. Comparison with other prevalence studies suggests that the ‘true’ prevalence of severe retardation (IQ 49 or below) for school-age children in the United Kingdom at the present time is approximately 3·6 to 4·0 per 1,000 (age-specific rate). About 40% of these children are also non-ambulant, or severely incontinent or have severe behaviour disorders. Early identification and plentiful provision of day places alone do not necessarily reduce the demand for residential accommodation. Detailed studies are needed to determine the factors which exacerbate or minimize the problems faced by families with severely retarded children.

Published drug trials with neurotic patients are surveyed and rating scales and other improvement criteria are tabulated and related to outcome. These findings are compared with the results of studies which were designed to evaluate the effectiveness of various improvement criteria. The principles of the construction of distress scales and the method of testing reliability and validity of scales which purport to measure changes are discussed.

Patients with ‘secondary’ affective disorder differ from those with ‘primary’ affective disorder in that there are additional symptoms of their pre-existing illness among the former. Hysteria, anxiety neurosis, antisocial personality, alcoholism, and drug dependency are the psychiatric conditions most frequently associated with ‘secondary’ affective disorders. There are other differences which may also be related to the presence of pre-existing illness. These differences include the findings that patients with ‘secondary’ affective disorder are younger, more often male, and are rarely manic; they suggest that it is appropriate to distinguish between ‘primary’ and ‘secondary’ affective disorder for research purposes.

The Clinical Research Department was started at Graylingwell Hospital, Chichester, Sussex, by Dr. J. Carse in 1947, when the hospital was administered by Sussex County Council. The first director was Dr. (now Professor) E. Stengel, and he undertook the first systematic follow-up of leucotomized patients. From 1950 to 1955 the director was Dr. Martin Roth; his studies on the psychoses of old age, and especially those delineating depressive psychoses, are now a landmark in clinical research. At about this time, the means by which clinical research in the National Health Service hospitals should be administered was reviewed and a policy evolved whereby departments in which clinical research was prospering and whose further development would make financial demands beyond those available to the regional hospital boards would be considered for support by the Medical Research Council.