Most people suffer from so-called ‘nervous symptoms' sometime during life, and their activity is influenced in varying degrees by these symptoms. There are a number of works reporting high prevalence of so-called neurotic symptoms: Rennie and his collaborators studied a sample of the population in the age range 20–59 of the central residential area of New York City and found that 75 per cent manifested significant symptoms of anxiety and that only 11 per cent of the lower class and 29 per cent of the upper class were psychiatrically symptom-free respondents (Rennie, Srole, Opler and Langner, 1957). Leighton found the life-time prevalence (after the age of 18) of psychoneurotic symptoms in a small town (population about 3,000) to be 67 per cent (Leighton, 1956). Winter interviewed 200 apparently healthy workers (mean age 36·6 years, 141 males and 59 females) of various social strata of Berlin, and found only 18 per cent free from so-called neurotic symptoms, i.e. anxiety, phobia, insomnia, headache and other psychosomatic symptoms (Winter, 1959). Agras, Sylvester and Oliveau found the prevalence of fear of storms, enclosures and journeying alone in females of Burlington to be 31 per cent, 14 per cent and 10 per cent respectively, and noted that psychiatrists saw only a small percentage of the phobic population (Agras, Sylvester and Oliveau, 1969). In all of these surveys, the authors noted that the majority of those with symptoms appeared to function well in the society. In Japan, a comparable survey is lacking, but Kasahara and Sakamoto investigated by questionnaire 2,481 students who entered Kyoto University in 1967 and found 24·1 per cent suffering from headache and 18 · 5 per cent from difficulty in falling asleep (Kasahara and Sakamoto, 1970). On 30 August 1970, N.H.K. (Japanese Broadcasting Corporation) invited to the studio 100 males who had graduated in 1945 from a single metropolitan all-male middle school for a programme entided ‘Age Forty’, in which health, economical and social status of this age group was enquired into. Among these, 26 ‘often suffered from palpitation and shortness of breath without significant exertion’, and 34 often awoke in the middle of the night or too early in the morning and could not get back to sleep again.