The original Psychoticism scale (P scale) of the Eysenck Personality Questionnaire (EPQ) had several psychometric shortcomings, including low reliability, a narrow score range, and a skewed distribution. To address these issues, a revised version of the P scale (EPQ-R) was developed. The revised scale includes 32 items, with 13 new items added to the original 25, and some modifications to the E and N scales. The revised scale also includes four short 12-item scales for P, E, N, and L. Two studies were conducted to evaluate the revised scale. The first study used a 90-item questionnaire with the EPQ P scale and potential new P items, while the second study used a 117-item questionnaire with all the 90 items of the EPQ plus new P items. The samples included 384 males and 290 females in the first study and 408 males and 494 females in the second study. The items were analyzed using factor analysis, and the revised scale showed improved reliability, a more normal distribution, and higher mean scores compared to the original scale. The revised P scale has a reliability of 0.78 for males and 0.76 for females, which is an improvement over the original scale. The score range has also increased, with means of 7.19 ± 4.60 for males and 5.73 ± 3.85 for females, compared to 4.15 ± 3.42 for males and 2.97 ± 2.59 for females in the original scale. The distribution of scores has also improved, with a somewhat reduced skewness and kurtosis. The revised scale also includes a short version with 12 items for each of the four scales, which is useful when time is limited. The short version has been shown to have acceptable reliability and is suitable for use in research. The revised scale has been shown to have good reliability and validity, and it is hoped that it will improve the usefulness of the EPQ-R in research, particularly in studies involving schizophrenia. However, the scale is still likely to have a slightly J-shaped distribution due to the nature of the items and the tendency of high P scorers to avoid cooperation.The original Psychoticism scale (P scale) of the Eysenck Personality Questionnaire (EPQ) had several psychometric shortcomings, including low reliability, a narrow score range, and a skewed distribution. To address these issues, a revised version of the P scale (EPQ-R) was developed. The revised scale includes 32 items, with 13 new items added to the original 25, and some modifications to the E and N scales. The revised scale also includes four short 12-item scales for P, E, N, and L. Two studies were conducted to evaluate the revised scale. The first study used a 90-item questionnaire with the EPQ P scale and potential new P items, while the second study used a 117-item questionnaire with all the 90 items of the EPQ plus new P items. The samples included 384 males and 290 females in the first study and 408 males and 494 females in the second study. The items were analyzed using factor analysis, and the revised scale showed improved reliability, a more normal distribution, and higher mean scores compared to the original scale. The revised P scale has a reliability of 0.78 for males and 0.76 for females, which is an improvement over the original scale. The score range has also increased, with means of 7.19 ± 4.60 for males and 5.73 ± 3.85 for females, compared to 4.15 ± 3.42 for males and 2.97 ± 2.59 for females in the original scale. The distribution of scores has also improved, with a somewhat reduced skewness and kurtosis. The revised scale also includes a short version with 12 items for each of the four scales, which is useful when time is limited. The short version has been shown to have acceptable reliability and is suitable for use in research. The revised scale has been shown to have good reliability and validity, and it is hoped that it will improve the usefulness of the EPQ-R in research, particularly in studies involving schizophrenia. However, the scale is still likely to have a slightly J-shaped distribution due to the nature of the items and the tendency of high P scorers to avoid cooperation.