Encyclopedia of Personality and Individual Differences

Living Edition
| Editors: Virgil Zeigler-Hill, Todd K. Shackelford

Neuroticism (Eysenck’s Theory)

  • Per BechEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-28099-8_1094-1

Keywords

Personality Trait Item Response Theory Item Response Theory Model Hamilton Depression Scale Eysenck Personality Questionnaire 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Synonyms

Definition

The Eysenck personality theory is based on the four classic temperaments (melancholic, choleric, phlegmatic, and sanguine) which Wilhelm Wundt integrated in the two dimensions of neuroticism and extraversion. Neuroticism covers the melancholic and choleric temperaments as a personality trait, i.e., a disposition-oriented tendency to react too emotionally in certain situations. Neuroticism, or emotionality, is the most distinct of Eysenck’s personality traits. It was also historically the first trait he defined. Thus, the Maudsley Medical Questionnaire (MMQ) was constructed to measure the personality trait of neuroticism. The MMQ contained 40 items. To cover both neuroticism and extraversion, the Maudsley Personality Inventory (MPI) was developed in 1956. A short version of the MPI containing six neuroticism items was published by Eysenck in 1958.

The Eysenck Personality Inventory (EPI) was developed by Eysenck and Eysenck in 1959. In this version, a Lie subscale was included to evaluate the respondent’s test-taking behavior, i.e., the extent to which the individual was “faking good.” The Eysenck Personality Questionnaire (EPQ) (Eysenck and Eysenck 1975) should be considered as the final measure of the Eysenck personality traits of neuroticism, extraversion (Bech 2017a), or psychoticism (Bech 2017b), still including the Lie subscale with 21 items. However, Eysenck et al. (1985) ultimately published a revised version (EPQ-R) in which one single extra item concerning the neuroticism scale was added to the 1975 version, but this item is of doubtful validity and is not included in the short-scale EPQ-R (Table 1). The Lie subscale in the EPQ-R was the unchanged 21-item version.
Table 1

The short-scale neuroticism items in EPQ-R (1985) with the corresponding item number in EPQ (1975) and the full EPQ-R (1985)

Item number

The neuroticism questions

Answer

Short-scale EPQ-R (1985)

EPQ (1975)

EPQ-R (1985)

Yes = 1

No = 0

1

3

3

Does your mood often go up and down?

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5

7

8

Do you ever feel “just miserable” for no reason?

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9

15

17

Are you an irritable person?

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13

19

22

Are your feelings easily hurt?

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17

23

26

Do you often feel “fed-up”?

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46

27

31

Are you often troubled about feelings of guilt?

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21

31

35

Would you call yourself a nervous person?

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25

34

38

Are you a worrier?

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30

41

46

Would you call yourself tense or “highly strung”?

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34

66

74

Do you worry a lot about your looks?

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38

75

83

Do you suffer from “nerves”?

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42

77

84

Do you often feel lonely?

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The key answer for each of the 12 items is “Yes” = 1 and consequently “No” = 0

Higher scores (from 0 to 12) indicate a higher degree of neuroticism

Introduction

From Eysenck’s first neuroticism scale (MMQ) in 1952 till the final neuroticism scale (EPQ-R) in 1985, the questions were worded in one direction so that the “Yes” response is related to the severity of neuroticism (Table 1). Eysenck and Eysenck (1969) conclude that to list the neuroticism items analogue to a list of symptoms in a depression scale is the most acceptable method. This is in concordance with De Vellis (2012) who has shown that the disadvantages of using items worded in opposite directions outweigh any benefits. The problems in the NEO Personality Inventory neuroticism scale (Bech et al. 2016a), in which items with opposite directions are incorporated, resulted in two subscales, one measuring euthymia and the other dysthymia. Kendell and DiScipio (1968) investigated formulating the Eysenck neuroticism items analogue to symptom depression scales. A fundamental requirement of any personality trait measure should be a relative independence when used in patients with a current state of depression so that the degree of depression severity is not reflected in their responses. Therefore, Kendell and DiScipio (1968) included the following instruction to the neuroticism scale: “Try to disregard your illness when answering these questions and answer ‘Yes’ or ‘No’ according to how you feel or behave when you are your usual self.” When measuring current states of depression or anxiety, we are focusing on relatively short-term conditions with a time frame of the past days or weeks. However, when measuring the frame of mind in determinate terms for dispositional statements, we are measuring a personality trait such as neuroticism (Bech 2016).

As a questionnaire for the personality trait of neuroticism, the Eysenck scale focuses on how the person feels or behaves when in his or her usual self so as to measure the dispositional traits, not the person’s momentary mood. This is in contrast to Cattell’s theory of neuroticism in which the current state is focused on, rather than on the fixed personality trait.

Psychometric Properties

The Validity of the Eysenck Neuroticism Scale by Factor Analysis

The final EPQ or EPQ-R neuroticism scale was psychometrically validated by several factor analytic studies, as was the very first version (the Maudsley Medical Questionnaire). The factor analytic identification of the neuroticism items versus the extraversion items in the Maudsley Personality Inventory illustrated by their lack of intercorrelations the psychometric factor validation of the two dimensions. Eysenck and Eysenck (1969) concluded that it was actually the Hotelling Principal Components solution rather than sophisticated factor rotations that identified these two main factors: neuroticism and extraversion.

The Clinical Validity of the Eysenck Neuroticism Scale

Eysenck never evaluated the clinical validity of his neuroticism scale. Thus, most of Eysenck’s factor analytic studies have been carried out on nonclinical populations, typically college students. Using a clinical population of patients with different types of depression, the EPQ neuroticism scale was evaluated, using an experienced psychiatrist with competence in neurotic disorders as index of clinical validity (Bech et al. 1986). When compared to other personality questionnaires, the EPQ neuroticism scale was the only one to correspond significantly with the experienced psychiatrist’s assessment.

The Validity of the EPQ Neuroticism Scale by Item Response Theory Analysis

The 23-item EPQ neuroticism scale was evaluated by the nonparametric item response theory model (Bech et al. 2016b). In this model, developed by Mokken, the scalability of the neuroticism scale is evaluated by a coefficient of homogeneity. In contrast to factor analysis, the Mokken analysis is a measurement model which evaluates to what extent the items can be ranked by their location on the latent dimension which is being tested, i.e., the degree of neuroticism. This is tested by the coefficient of homogeneity. A coefficient value of 0.40 or higher indicates a clear scalability, implying an additive structure of the items, i.e., that their summed total score is a sufficient measure of neuroticism. Bech et al. (2016a, b) obtained a coefficient of homogeneity of 0.43 in the EPQ neuroticism scale in patients with first episode of depression who had completed the neuroticism scale when in remission from their depression.

The Predictive Validity of the Eysenck Neuroticism Scale

The dispositional nature of the Eysenck neuroticism scale implies that predictive validity is inherently the most important part of its validity. The patients mentioned above who were tested after remitting from their first-episode depression (Bech et al. 2016a, b) were reanalyzed at a 5-year follow-up interview. Using the Hamilton Depression Scale with a score of 8 or more at the 5-year follow-up interview as criterion of validity, it was found (Bech et al. 2016b) that the Eysenck neuroticism scale (a score of 14 or more) was able to predict depression, in contrast to the Hamilton Depression Scale (P < 0.05).

In another study using the EPI neuroticism scale, an attempt was made to identify the items which predicted non-remission after 6 months of treatment in patients with generalized anxiety disorder (Bech and Rickels 2016). In this study, a score of 8 or more on the Hamilton Anxiety Scale was the criterion of non-remission. Six items in the EPI neuroticism scale were identified as the most significant predictor items of non-remission. When using the neuroticism items from the short-scale EPQ-R, five of the six items are included (Table 1), namely, being a nervous person, feeling easily hurt, mood goes up and down, feeling miserable, and guilt feelings. Only the item of sleeplessness, which is the remaining somatic neuroticism item in the EPQ or EPQ-R when compared to the original MMQ, is missing.

Conclusion

When using the Eysenck neuroticism scale, it is important to indicate which version is being tested. The EPQ neuroticism scale (Eysenck and Eysenck 1975) with its 23 items is still the most used internationally. Very few studies with the 24-item EPQ-R (Eysenck et al. 1985) have been published. The great strength of the EPQ neuroticism scale is its validity (clinical validity, psychometric scalability, and predictive validity). Neuroticism is the most distinct personality trait in the EPQ. The neuroticism factor in the NEO Personality Inventory is also the most distinct of the five factors included in this scale. However, from a psychometric point of view, the EPQ neuroticism scale should be considered the most important. It is about as good as can be desired (Kline 1993).

References

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Copyright information

© Springer International Publishing AG 2016

Authors and Affiliations

  1. 1.University of CopenhagenHillerødDenmark

Section editors and affiliations

  • Beth A. Visser
    • 1
  1. 1.Lakehead UniversityOrilliaCanada