Factor analysis was conducted on responses to the CCEI of the following population samples: 120 normal men; 117 normal women; 115 male psychiatric patients; and 180 female psychiatric patients. Factor correlations between the 4 samples were calculated using Cattell's S index. Components reflecting the subscales Obsessionality, Hysteria and Phobic Anxiety appeared in at least 3 of the 4 samples, and were strongly intercorrelated, confirming the factorial reliability of these subscales. These findings are consistent with previous psychometric research on the CCEI. A component reflecting Somatic Anxiety appeared only in the female patient sample. The Depression subscale was clearly represented in the first component derived from all 4 samples, but in association with items from other subscales. A component corresponding to the subscale Free Floating Anxiety did not appear in any sample, and some reasons for this were proposed. It was concluded that the CCEI remains a reliable, valid and convenient instrument for research into neurotic disorders. The addition of a new subscale to assess symptoms related to Panic Disorder was suggested, together with some minor modifications that would facilitate the use of the CCEI as a measure of changes in symptoms over time.