The Revised Obsessive Intrusion Inventory (ROII) is a 52-item scale that evaluates obsessional intrusive thoughts. The aim of the present study was to validate a short, 20-item Korean version of the ROII (ROII-20).
Of the 1125 participants who completed the ROII-20, 895 participants completed the scale to examine the factor structure of the scale. A subgroup of these participants (n=53) completed the scale twice to determine test-retest reliability. To establish external validity, 230 participants completed the scale and other questionnaires.
Exploratory factor analyses suggested a hierarchical model comprising two higher order factors of autogenous obsessions (resulting from aggressive thoughts and sexual thoughts) and reactive obsessions (resulting from thoughts about contamination, thoughts about accidents, and thoughts about dirt). Confirmatory factor analyses supported this model. The results indicated good internal consistency and test-retest reliability. External validity was supported by relationships with obsessive-compulsive symptoms and general distress.
The ROII-20 presents good psychometric properties and may be considered as a promising instrument for measuring obsessional intrusions.
Obsessions are recurrent and persistent thoughts, impulses, or images that are experienced as intrusive and inappropriate, causing marked anxiety or distress.
Another important factor that should be considered is the content of mental intrusions. Mental intrusions have various contents (e.g., aggressive thoughts, sexual thoughts, contamination related thoughts, and accident-related thoughts), which are related to cognitive appraisals and neutralization strategies.
This evidence suggests that contents of mental intrusions, or at least the subtype of mental intrusions (i.e., AOs vs. ROs), should be considered when measuring mental intrusions. The Revised Obsessive Intrusion Inventory (ROII)
Although the ROII is a reliable and valid measure for assessing mental intrusions in terms of content and frequency, it still has several limitations. First, the ROII is composed of 52 items, which is relatively time-consuming to complete and could hinder its use both in research and clinical contexts. Second, it addresses various thought contents but certain contents are assessed in much greater proportion than others: 41 items assess AOs and 11 items assess ROs.
Considering these limitations of the ROII, the aim of the current study was to develop a short version of the ROII assessing mental intrusions with a balanced proportion of thought contents. To this end, we examined the psychometric properties (factor structure, internal consistency, test-retest reliability, and external validity) of the short, 20-item Korean version of the ROII (ROII-20).
The sample comprised 1125 undergraduate students (50.1% female) from two universities in Seoul. The students participated in this study in partial fulfillment of their research participation credit. Only native Korean speakers were retained for the study. The age of the participants ranged from 17 to 35 years (mean=21.86 years, SD=2.47).
Groups of 50 to 100 individuals completed the ROII-20 and other measures in their university classes. The questionnaires were completed anonymously, and all participants provided informed consent. One subgroup of participants (n= 431) completed the ROII-20 for Exploratory Factor Analyses (EFA). Some participants in this subgroup (n=52) completed the ROII-20 twice (with an interval of four weeks) to establish test-retest reliability. A personal code instead of an identity was used to monitor these participants across sessions. A second subgroup of participants (n=464) completed the scale for Confirmatory Factor Analyses (CFA). A third subgroup of participants (n=230) completed the ROII-20 and other self-report measures to determine external validity of the ROII-20.
The ROII-20 is a 20-item scale that evaluates two different subtypes of mental intrusions labeled as AOs and ROs. All items are scored on a Likert scale from 0 ("never") to 6 ("frequently during the day"). The items of the ROII-20 were taken from the 52-item Korean version of the ROII.
The Obsessive-Compulsive Inventory-Revised (OCI-R) is a well-established 18-item questionnaire assessing the severity of OCD symptoms with good psychometric properties: internal consistency, test-retest reliability, and convergent validity.
The Padua Inventory-Washington State University Revision (PIWSUR) is a 39-item questionnaire that assesses the severity of OCD symptoms with good reliability and validity.
The Centers for Epidemiologic Studies Depression Scale (CES-D) is a 20-item questionnaire assessing depressive symptoms with good psychometric properties.
The Beck Anxiety Inventory (BAI) is a widely used 21-item questionnaire assessing anxiety symptoms.
To examine the factor structure of the ROII-20, we conducted EFA with maximum likelihood extraction and direct quartimin rotation. We also performed CFA with R (version 3.0.1, lavaan package)
Of the 1125 participants, 51 had one item or more missing after completion of the questionnaires and were removed from the analyses. EFA was conducted with 410 participants. These participants were divided into two subgroups. The lower-order EFA was conducted with a subgroup (n=305) to examine the lower-order factor structure of the ROII-20. Eigenvalues of the correlation matrix suggested a five-factor structure (five eigenvalues >1.0). The five-factor model showed an acceptable fit (RMSEA=0.07) and explained 71.5% of the total variance. The detailed factor loadings are reported in
We conducted CFA with 434 participants to confirm the factor structure of the ROII-20. The hierarchical model that we obtained from the EFA was tested by maximum likelihood estimation. The results showed that the hierarchical model had an acceptable fit [χ2 (164)=488.43, p<0.001; RMSEA=0.07; SRMR=0.05; CFI=0.93]. This model is depicted in
Mean, SDs, internal consistency coefficient (Cronbach α), and test-retest reliability indices for the components of the ROII-20 are reported in
The present study examined the psychometric properties of a short version of the Korean adaptation of the ROII developed by Purdon and Clark.
The completion time of the original 52-item scale is approximately 13 min (15 seconds per item), whereas the ROII-20 takes only 5 min to complete. This significant time saving is only justified if the psychometric properties of the short-form measure remain largely comparable to those of the original measure.
We developed the ROII-20 by retaining the 10 items that loaded most strongly on each of the two factors (AOs and ROs). Although this technique has been frequently used to develop short-form measures, it has the limitation that selected items reflect narrower constructs.
In the present study, we examined the external validity of the ROII-20 using several measures tapping OCD symptoms and general distress (i.e., depression and anxiety), and we were able to determine the scale's convergent validity and criterion validity. Moreover, we examined the differential relationships between the AOs/ROs subscales and two measures tapping OCD symptoms to determine the subscales' discriminant validity. The discriminant validity of the whole scale, however, has yet to be established. Because mental intrusions are similar to other unwanted cognitions (e.g., worry)
ROII-20: Revised Obsessive Intrusion Inventory-20
ROII-20: Revised Obsessive Intrusion Inventory-20
*p<0.01. ROII-20: Revised Obsessive Intrusion Inventory-20
*p<0.05, **p<0.01. OCI-R: Obsessive Compulsive Inventory-Revised, PI-impulses: Padua Inventory Washington State University Revision: obsessional impulses subscale, BAI: Beck Anxiety Inventory, CES-D: Centers for Epidemiologic Studies Depression Scale, AG: aggressive thoughts, SX: sexual thoughts, CN: thoughts about contamination, MI: thoughts about mistakes and accidents, DR: thoughts about dirt/ordering/cleaning, AOs: Autogenous obsessions, ROs: Reactive obsessions, ROII-20: Revised Obsessive Intrusion Inventory-20