Information theory is sometimes presented as a new philosophy; here it will be presented as an essentially practical branch of science. Its essence occurs when an engineer says: “You can't get ten manoeuvres out of that satellite when you've only five signals.” He is thinking along the usual and well understood lines of cause and effect, but using a rather unusual approach: instead of trying to relate each cause to its particular effect (e.g. “what is the cause of tuberculosis?”), he is bringing a set of (five) causes into some relation with a set of (ten) effects. Throughout this article, information theory will be used in accordance with what I believe to be its true nature—that it is the body of knowledge developed to help when we have problems in which large numbers of causes are related in some way to large numbers of effects.

From time to time, normal human beings not suffering from any mental illness have reported experiences either akin to or identical with hallucinations (Byrd, 1938; Slocum, 1948; Ritter, 1954; Bombard, 1955). The common features in these reports have been the social isolation of the people involved and the physical hardships of their living conditions. They have usually been solitary mariners or polar explorers. Scientific interest was not aroused in these phenomena until directed to them by the experiences of prisoners of war in Korea who had undergone “brain-washing” techniques. At this time, Hebb and his colleagues began a series of experiments which opened up an era of widespread research into the field of Sensory Deprivation.

The immense literature on schizophrenia abounds in discoveries of single associations between the symptoms of the disease and certain other factors. Braithwaite (1960) says in speaking about “science like psychology and the social sciences which make great use of tendency statements… that to assert an isolated tendency statement is to say very little”. Such isolated statements in themselves are not explanations. A theory, on the other hand, interprets information; it explains.

The traditional concept of manic-depressive psychosis has been either a bi-polar or a circular one, used interchangeably. The psychoanalytic school has invoked the polarity of much of human behaviour as an appropriate analogy. For example “The tragedy is succeeded by the satyr play: after the serious worship of God comes the merry fair… On the same basis the same sequence is represented by the cycle of guilt feelings and unscrupulousness, later by the sequence of guilt feelings and forgiveness…. The manic-depressive cycle is a cycle between periods of increased and decreased guilt feelings: … this cycle, in the last analysis, goes back to the biological cycle of hunger and satiety in the infant” (Fenichel, 1946, p. 409).

Research in stuttering can be divided into two broad categories. The focus of attention has either been on the way the stutterer speaks or on the sort of person he is. In the first case, investigators have sought to isolate those conditions under which the stutterer's blocks, repetitions, or prolongations can be modified. For instance, there are studies on the effects of varying the size of the audience (e.g. Siegel and Haugen, 1964; Shulman, 1955), of providing delayed auditory feedback (e.g. Lee, 1951; Neeley, 1961) or various levels of noise (e.g. Mariast and Hutton, 1957; Sutton and Chase, 1961), and on the relationship between number of stutters and rhythmic speech (e.g. Barber, 1940; Fransella and Beech, 1965).

In 1932 Monroe wrote that “inability to read may be one of the prolonged school problems to which parents and agencies become adapted until the child drifts into truancy and incorrigibility”. This observation, if true, is highly pertinent to the problems of present day society, and, for this reason, a personal study was made of delinquent boys between the ages of 12 and 17 years referred by the courts for assessment at a London Remand Home and Classifying Centre.

Few psychiatric controversies have been as persistent as the disagreement surrounding the nosology of depression. The conflict centres on the question of whether depression is a single illness, with its many faces manifestations of individual idiosyncrasy and severity, or whether it constitutes two or more separate conditions. The 1926 debate at the British Medical Association Meetings, with Edward Mapother (11) propounding the case for a single illness and Buzzard and Ross advancing claims for a dichotomy, has in one form or the other continued until today. The issue is complicated by the fact that few terms in psychiatry are used with as many different meanings as depression. Unfortunately the use of the term is seldom clearly defined. As Humpty Dumpty said in Through the Looking-Glass, “it means just what I choose it to mean—neither more nor less”.

The relationship between ordinal position of birth and mental illness, and particularly schizophrenia, is a familiar issue to regular readers of this journal. Its significance rests mainly in the fact that on genetic grounds each ordinal position of birth in a sibship is equally vulnerable. Therefore conclusive evidence of a positive relationship between birth order and mental illness, while not excluding the importance of hereditary factors, offers a good indication of the operation of some, possibly early, familial environmental influences.

In another paper (Grosz, 1968) I reported that among 267 depressive patients from three sibling families admitted to the Bethlem Royal and Maudsley Hospitals, London, the middle born were significantly (p·001) over-represented and the youngest born under-represented among patients with two differently sexed siblings. There was no significant birth order effect among depressive patients with two same-sexed sibs (i.e. with either two brothers or two sisters).

The specific therapeutic effect of lithium salts in the treatment of the manic phases of manicdepressive psychosis was first reported by Cade (1949) and has been confirmed in a number of studies since (Schou, Juel-Nielson, Strömgren and Voldby, 1954; Maggs, 1963; Hartigan, 1963). In view of the claims made by Baastrup (1964) and more recendy by Baastrup and Schou (1967) that lithium also has a prophylactic action against both manic and depressive phases of manic-depressive psychosis it is likely that lithium salts will be used increasingly by psychiatrists.

The Coloured people of the Cape Peninsula have evolved over three hundred years as a demarcated ethnic group with recognizable physical features and characteristic cultural and social conditions. As such they constitute a very satisfactory population for epidemiological and transcultural studies, and when the need arose to plan for improved psychiatric services, a large-scale field survey of the prevalence and types of mental illness was set afoot. Since socio-economic circumstances appear to be very relevant to the amount and type of mental illness in a community, special estimations of these were also made. Random sampling of the entire population of Coloured persons over 20 years of age in the magisterial area of the Cape Peninsula was done and 500 of a total population of 200,365 people were interviewed about their mental and physical health, as well as a variety of economic and social circumstances, by a team of three psychiatrists and 14 specially trained social workers. In addition, interviews were held with reliable persons who knew each respondent, such as ministers of religion, social workers, housing managers, nurses, doctors, friends, relations, and employers. Hospital records were consulted as necessary, and the information was evaluated for each respondent by a team of three psychiatrists. The data were coded and finally exposed to an extensive computer and statistical analysis.

All male patients above 180 cm. tall who were resident in the Århus State Hospital on 13 April, 1966, were registered: they numbered 42 out of the total of 440 resident males (8 · 1 per cent.). One patient, a 78-year-old man, died before chromosome analysis was made. Sex-chromatin analysis was made on Feulgenstained buccal smears and chromosome analysis was made on leucocyte cultures according to the method described by Moorhead et al. (1960), slightly modified. Not less than 25 metaphases were counted, at least 15 metaphases with the modal figure and all metaphases with a chromosome number deviating from the modal figures were analysed.

The life expectation of even the most severely subnormal patients in hospital with IQs below 25, has risen dramatically since the beginning of the century. This paper reports the results of a survey carried out by the author into the expectation of life of patients with IQs up to 50 in the Stoke Park Hospital Group, Bristol.