1. The EEG of the psychoneurotic patient shows no gross abnormalities of wave pattern and in general falls within the normal range.2. Nevertheless, a study of the findings on a group of 100 psychoneurotic patients reveals that their electroencephalographic data lie only just within the range for normals and that the distribution of their data is statistically different from that of a group of 500 normal adults.3. The statistically significant differences between the total psychoneurotic group and the normal group were in the following characteristics of the EEG.(a) The distribution curve of dominant frequencies in the psychoneurotic group was not that of a normal population.(b) The incidence of beta activity (18. o cycles and over) was higher in the psychoneurotic group than in the normals.4. The clinical subgroup diagnosed as anxiety neurosis had a normal distribution curve for dominant frequencies but in a range faster than normal (mean 11.2 for anxiety neurosis as against 10.6 for normals).5. A discussion is presented of the possible physiological mechanism which may be responsible for these findings.Abstract Teaser