The NEO-PI-R is a self-report instrument that measures the five most important domains of personality: neuroticism, extraversion, openness, agreeableness and conscientiousness (section: mental health)¹⁾.
Lifelines implemented two abbreviated versions of the NEO at baseline, focusing on the domains of neuroticism, extraversion and conscientiousness.
Note that personality traits were also assessed in Lifelines using the ASI, the GAS, and the Type D instrument. Moreover, various personality traits (hostility, reward sensitivity) were assessed in the context of an an additional questionnaire on ADHD and questions from the NEO-FFI on aesthetic sensitivity have been included in the additional questionnaire SPEQ. Sum scores for the NEO personality questionnaire are available for use.

The original complete NEO-PI questionnaire contains 240 items: 8 items per facet, 6 facets per domain (see table).

Lifelines used an abbreviated 64-item version of the NEO until september 2012, containing eight personality facets that were selected based on their influence on psychopathology (according to the NEO manual)²⁾:

From september 2012 onwards, Lifelines used an abbreviated 99-item version of the NEO. For each of the five domains, the makers of the scale have indicated 12 key items, the so-called “FFI items”.
The facets Anxiety (8 items) and Depression (8 items) were added to complete the domain of Neuroticism.
9 items for Conscientiousness were added to cover the NEO-Five Factor Inventory (FFI) scales for this domain.
10 items for Extraversion were added, resulting in 11 out of 12 items for the FFI Extraversion domain. One variable (“I really enjoy talking to people”) was omitted³⁾⁴⁾.

The construct vailidity of the NEO-PI-R Neuroticism subscale has been tested against different tests, namely the AB5C (“Abridged Big Five-Dimensional Circumplex”) for Emotional stability, the ABV (“Amsterdamse Biografische Vragenlijst“) for Neuroticism, the B5BBS25 (Flemish set of bipolar markers for the Big-5 personality-factors) for Stability and the 5PFT (“Vijf persoonlijkheids-faktoren test “) for Neuroticism. The exact statistics and construct validity can be found in the Manual by Hoekstra et al.

The NEO-FFI scales for Extraversion and Conscientiousness have been correlated to 4DPT (“Vier Dimensionale Persoonlijkheidstest”) scales (population unknown): NEO-FFI Extraversion – 4DPT Extraversion: 0.84 NEO-FFI Conscientiousness - 4DPT Ordelijkheid: 0.50

For both the NEO-PI-R (Neuroticism) and the NEO-FFI (Extraversion, Conscientiousness) the internal consistency was tested. For the NEO-FFI (Extraversion, Conscientiousness) the stability was tested. The exact statistics for the internal consistency and stability of both tests can be found in the Manual by Hoekstra et al.

1. Zijlema et al. (2015). Noise and somatic symptoms: A role for personality traits? International Journal of Hygiene and Environmental Health 218(6): 543-549
2. Realo et al. (2017). SNP-Based heritability estimates of common and specific variance in self- and informant-reported neuroticism scales. Journal of Personality 85(6): 906-919
3. Brouwer et al. (2020). Personality as a resource for labor market participation among individuals with chronic health conditions. International Journal of Environmental Research & Public Health 17(17): 6240