Olav Vassend

Anxiety, pain and discomfort associated with dental treatment

The aims of the study were to describe the level of anxiety and pain/discomfort associated with dental treatment in two samples (N = 1288 and N = 2382) representative of an adult population, and to assess the statistical effects of these variables on utilization of dental services (dental attendance measures, expenditure, and items of dental treatment received during the last year). The prevalence of high dental anxiety in the samples as measured by Corahs Dental Anxiety Scale, the Dental Fear Scale, and the Dental Anxiety Question was 4.2%, 7.1% and 5.4%, respectively. Rather large proportions of the respondents judged dental treatment to be painful or uncomfortable: between 20 and 30% rated their last dental visit as moderately painful or worse; about 60% reported having had at least one very painful experience, and 5-6% experienced dental treatment in general to be very painful. Dental anxiety was significantly related to pain reports (correlations in the 0.32-0.48 range). There were no differences between the youngest age group (15-19 yr) and the rest of the respondents in Study II with regard to dental pain ratings. Possible explanations for these findings are discussed. The effects of dental pain and anxiety on utilization measures, although attaining significance in several of the analyses, were generally weak. Both studies demonstrated few significant differences between individuals with high dental anxiety and the rest of the study samples with respect to type and extent of dental treatment received during the last year. Thus, these data seem to show that many dentally anxious patients seek out and undergo dental treatment despite high fear levels.

Individual differences in pain sensitivity: Genetic and environmental contributions

&NA; Large individual differences in pain sensitivity present a challenge for medical diagnosis and may be of importance for the development of chronic pain. Variance in pain sensitivity is partially mediated by genetic factors, but the extent of this contribution is uncertain. We examined cold‐pressor pain and contact heat pain in 53 identical (MZ) and 39 fraternal (DZ) twin pairs, and 4 single twins to determine the heritability of the two phenotypes, and the extent to which the same genetic and environmental factors affect both pain modalities. An estimated 60% of the variance in cold‐pressor pain and 26% of the variance in heat pain was genetically mediated. Genetic and environmental factors were only moderately correlated across pain modalities. Genetic factors common to both modalities explained 7% of the variance in cold‐pressor and 3% of the variance in heat pain. Environmental factors common to both modalities explained 5% of variance in cold‐pressor and 8% of the variance in heat pain. The remaining variance was due to factors that were specific to each pain modality. These findings demonstrate that cold‐pressor pain and contact heat pain are mainly distinct phenomena from both a genetic and an environmental standpoint. This may partly explain disparate results in genetic association studies and argues for caution in generalizing genetic findings from one pain modality to another. It also indicates that differences in pain scale usage account for a minor portion of the variance, providing strong support for the validity of subjective pain ratings as measures of experienced pain.

The problem of structural indeterminacy in multidimensional symptom report instruments. The case of SCL-90-R

The factor structure of SCL-90-R items and scales was analyzed using both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Results of CFA studies at the item-level failed to support the original nine-factor model, as well as several alternative models and EFA suggested very different dimensionality, depending on which criteria were used. Analyses at the scale-level (i.e. the nine original symptom dimensions) suggested that a one- or two-factor model was satisfactory according to descriptive goodness of fit criteria. However, using the likelihood ratio test, specification of four factors was necessary to avoid rejection. According to the likelihood ratio test in a multi-group analysis, a lack of factorial invariance across gender was indicated. Moreover, the factorial structure of the instrument was clearly different across levels of negative affectivity (NA); the dimensionality was substantially higher in the low-NA group as compared to the high-NA group. It is concluded that we are confronted with a profound structural indeterminacy problem and that factor analytic methods and model acceptance criteria alone are insufficient to solve this problem. The indeterminacy problem can be accounted for, at least in part, by the complex logical-semantical structure of SCL-90-R items and scales and the role of the NA trait as a structure generating factor.

Validation of the NEO Personality Inventory and the five-factor model. Can findings from exploratory and confirmatory factor analysis be reconciled?

The aims of the study were (i) to analyse a Norwegian version of the NEO Personality Inventory (NEO‐PI), using both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA); (ii) to compare the results of the two factor analytic strategies, both within the present study and across different studies; and (iii) to discuss possible causes of discrepant findings (across factor‐analytic methods and across samples). The sample comprised 961 subjects representative of the non‐institutionalized Norwegian adult population. Using an EFA strategy, very high coefficients of factor comparability (r=0.93–0.99) across sexes were found. None of the five main domains turned out to be as homogeneous as suggested by the original five‐factor model, but most of the deviations from the assumed simple structure were comparable to results from recent American studies. However, none of the revised EFA‐based models were supported using CFA methods. Moreover, a large number of modifications were necessary to obtain a model with acceptable fit. It is argued that these discrepant findings can be accounted for, at least in part, by (i) consequences of different model acceptance criteria in the EFA and CFA tradition, (ii) the inherent logical–semantical structure of the NEO‐PI, and (iii) consequences of selection effects (factorial invariance problem).

A comparison of cognitive therapy, applied relaxation, and nitrous oxide sedation in the treatment of dental fear.

The aim of this study was to investigate the short-term efficacy of cognitive therapy and applied relaxation in dental fear treatment and to compare these methods with conventional pharmacological sedation (nitrous oxide sedation). Patients (n = 65) with severe dental fear were randomly assigned to the different treatment methods and received 10 weekly sessions of individual therapy. Dropout rates were low, and all patients who completed the therapy sessions were able to receive dental treatment. Scores on dental fear tests were significantly reduced compared with pretreatment level for all treatment groups. There were no major differences between treatment methods in this short-term perspective.

Characterizing individual differences in heat-pain sensitivity

Abstract Heat induced pain has been shown to follow a positively accelerating power function for groups of subjects, yet the extent to which this applies to individual subjects is unknown. Statistical methods were developed for assessing the goodness of fit and reliability of the power function for data from individual subjects with the aim of using such functions for characterizing individual differences in heat‐pain sensitivity. 175 subjects rated ascending and random series of contact heat stimuli with visual analogue scales for pain intensity (VAS‐I) and unpleasantness (VAS‐A). Curve fitting showed excellent model fit. Substitution of model estimates in place of observed VAS scores produced minimal bias in group means, about 0.3 VAS units in the ascending series and 1.0 in the random series, on a 0–100 scale. Individual power function exponents were considerably higher for the ascending than for the random series and somewhat higher for VAS‐A than for VAS‐I (means: ascending VAS‐I=9.04, VAS‐A=9.80; random VAS‐I=4.95, VAS‐A=5.67). The reliability of VAS estimates was high (≧.93), and for the ascending series it remained so when extrapolating 4 °C beyond the empirical range. Exponent reliability was high for the ascending series (VAS‐I=.92; VAS‐A=.91), but considerably lower for the random series (VAS‐I=.69; VAS‐A=.71). Individual differences constituted 60% of the total variance in pain ratings, whereas stimulus temperature accounted for only 40%. This finding underscores the importance of taking individual differences into account when performing pain studies.

Dimensions of negative affectivity, self-reported somatic symptoms, and health-related behaviors

This study focused on the relationship between personality dispositions, self-reported somatic symptoms, and health-related behaviors in undergraduate students. Findings are presented which indicate systematic correlations between health complaints and negative affectivity (NA), a common and pervasive mood disposition. Generally, there was a stronger relationship between NA and self-reported somatic symptoms than between NA and variables reflecting health-related behaviors, lifestyle, and general fitness. Significant correlations between health complaints and capacity for imaginative involvement (absorption), as well as self-reported measures of emotional inhibition, were also demonstrated. However, it is uncertain whether absorption and emotional inhibition properly belong to the NA construct. The results also indicated differences with respect to the strength of the associations between various dimensions of NA and particular types or classes of health complaints. For example, cognitive anxiety (e.g. worry, ruminations, disturbing thoughts) was more strongly related to somatic complaints than behavioral (social avoidance) components of anxiety. Moreover, diffuse and widespread symptoms (e.g. weakness and fatigue) were more strongly associated with NA than more specific and localized symptoms, particularly musculo-skeletal complaints, although complaints belonging to the musculoskeletal category obtained the highest group mean score. The results strongly suggest that a differentiated approach to the study of NA-symptom connections should be adopted.

Negative affectivity, somatic complaints, and symptoms of temporomandibular disorders

This study examined the relationship between trait anxiety, subjective somatic symptoms, and pain associated with temporomandibular disorders (TMD) in a combined cross-sectional and prospective study. Compared with the initial measurements, a significant reduction in anxiety and pain was observed in the follow-up phase (two years after evaluation and therapy). No change in general somatic complaints was found. In both the initial phase and the follow-up phase, a consistent relationship between anxiety, somatic complaints, and TMD-related pain was demonstrated. The results are in agreement with a conceptualization of negative affectivity (e.g., anxiety, distress, tension) as a general dimension of somatopsychic distress. The best predictors of later TMD pain were general somatic complaints, followed by initial pain, and trait anxiety. Significant moderate correlations between anxiety, somatic complaints, and response to muscle palpation (feelings of tenderness) were also found. It is concluded that studies of TMD should incorporate measures of negative affectivity and general somatic complaints because these factors are important predictors of TMD pain, response to treatment, and chronicity.

Effects of examination stress on some cellular immunity functions

The effects of examination stress on some lymphocyte subpopulations and cellular immune responses are reported. Twelve undergraduate students of psychology in examination term were tested six weeks before the written examination (phase I), one day before the first or second examination day (phase II) and 12-14 days after the examination (phase III). A comparable control group of students not in examination was assessed in parallel in phase II. The percentage of circulating monocytes increased in phase II in the examination group whereas the percentage of large (probably activated) CD4 and CD8 cells decreased. There was also a decrease in the number of cells expressing the IL-2 receptor in phase II. The proliferative response of T-cells to antigens, mitogens and allogeneic cells decreased from phase I to phase III. Thus, acute examination stress has a detectable influence on certain cellular immunological functions.

Factor analytic studies of the neo personality inventory and the five-factor model: The problem of high structural complexity and conceptual indeterminacy

Abstract The purpose of the study was threefold: (1) to analyze the NEO Personality Inventory (NEO-PI) and the five-factor model—using both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA)—with the aim of establishing a Norwegian version of the instrument; (2) to compare the results of the analyses with the original NEO-PI simple structure five-factor models as well as later revisions of the model; and (3) to discuss causes of variations that are found in the NEO-PI literature on structural representations of personality traits. The sample comprised 973 subjects representative of the non-institutionalized Norwegian adult population. On the whole, compared with the original five-factor model and later (minor) revisions, both EFA- and CFA-strategies indicated a much more complex and fine-grained structure of items and scales. However, most of the discrepancies relative to the original model(s) were comparable to findings from recent American and German studies. Moreover, content analyses of the revised five domains as well as facets (sub-scales) indicated acceptable conceptual interpretability and plausibility. Thus, judged by conventional (mostly EFA-based) methods and criteria, the Norwegian NEO-PI version appears satisfactory in several respects. Nevertheless, it is claimed that the whole field of research is characterized by a profound conceptual indeterminacy. This problem stems largely from (1) the lack of explicit criteria-based definitions of essential concepts, and the corresponding reliance on rather arbitrary indicators (symptoms) of the alleged underlying dimensions; (2) the semantical-logical complexity of items and scales and the high probability of conceptual cross-linking; (3) the widespread tendency to define constructs on the basis of (empirical) covariance structures instead of inherent conceptual features; and (4) the masking of structural complexity by the extensive use of EFA-based methods and criteria to approximate simple structure.