Genetic and environmental contributions to the co-occurrence of depressive personality disorder and DSM-IV personality disorders

One of the main controversies with regard to depressive personality disorder (DPD) concerns the co-occurrence with the established DSM-IV personality disorders (PDs). The main aim of this study was to examine to what extent DPD and the DSM-IV PDs share genetic and environmental risk factors, using multivariate twin modeling. The DSM-IV Structured Interview for Personality was applied to 2,794 young adult twins. Paranoid PD from Cluster A, borderline PD from Cluster B, and all three PDs from Cluster C were independently and significantly associated with DPD in multiple regression analysis. The genetic correlations between DPD and the other PDs were strong (.53-.83), while the environmental correlations were moderate (.36-.40). Close to 50% of the total variance in DPD was disorder specific. However, only 5% was due to disorder-specific genetic factors, indicating that a substantial part of the genetic vulnerability to DPD also increases the vulnerability to other PDs.     

Bicycle helmets – A case of risk compensation?

Several studies have shown that bicycle helmets have the potential of reducing injuries from accidents. Yet, no studies have found good evidence of an injury reducing effect in countries that have introduced bicycle helmet legislation. Two of the most promising explanations for why helmet laws do not work as intended are risk compensation and shifts in the cycle population as a response to the law.The present article investigates whether the lack of effect of helmet wearing laws is due to risk compensation mechanisms or population shifts (i.e. discouraging cyclists with the lowest accident risk, and thereby increasing the overall average risk per cyclist). A random sample of 1504 bicycle owners in Norway responded to a questionnaire on among other things helmet use, bicycle equipment use, accident involvement, cycling behaviour and risk perception. Data were analysed by using structural equation model (SEM). The results show that the cyclist population in Norway can be divided into two sub-populations: one speed-happy group that cycle fast and have lots of cycle equipment including helmets, and one traditional kind of cyclist without much equipment, cycling slowly. With all the limitations that have to be placed on a cross sectional study such as this, the results indicate that at least part of the reason why helmet laws do not appear to be beneficial is that they disproportionately discourage the safest cyclists.     

Development of a Facebook Addiction Scale

The Bergen Facebook Addiction Scale (BFAS), initially a pool of 18 items, three reflecting each of the six core elements of addiction (salience, mood modification, tolerance, withdrawal, conflict, and relapse), was constructed and administered to 423 students together with several other standardized self-report scales (Addictive Tendencies Scale, Online Sociability Scale, Facebook Attitude Scale, NEO-FFI, BIS/BAS scales, and Sleep questions). That item within each of the six addiction elements with the highest corrected item-total correlation was retained in the final scale. The factor structure of the scale was good (RMSEA = .046, CFI = .99) and coefficient alpha was .83. The 3-week test-retest reliability coefficient was .82. The scores converged with scores for other scales of Facebook activity. Also, they were positively related to Neuroticism and Extraversion, and negatively related to Conscientiousness. High scores on the new scale were associated with delayed bedtimes and rising times.     

Adolescent smoking behavior and outcome expectancies

Adolescent smoking behavior is assumed to be associated with smoking outcome expectancies. Results in this paper are based on data from the control group of two data collections among Norwegian secondary school students taken approximately 30 months apart (T1 and T2). The dimensionality of smoking outcome expectancies was the same at both time points, revealing three components ("Addicted", "Not harmful" and "Social"). After correction for attenuation, the Pearson's correlation between T1 and T2 was 0.41 for the total sumscore, indicating low to moderate relative stability. When examining smoking expectancy sumscore means by smoking habits at T1 and T2, never smokers were different from smokers on both occasions. Never smokers scored low on "Social" and "Not harmful", and high on "Addictive". All associations were statistically significant (p < 0.001). The "Social" dimension was the strongest predictor of smoking behavior at T1 and T2. One of the outcome expectancy sumscores ("Addictive") at T1 predicted smoking habits at T2 after controlling for smoking habits at T1 (p < 0.01). This predictor was significant also after entering outcome expectancy sumscores at T2 into the model (p < 0.05). These results indicate that outcome expectations other than the health-related ones should be paid attention to when planning new prevention programs.     

Changes in natural language use as an indicator of psychotherapeutic change in personality disorders

Word use has been shown to reflect various psychological processes and psychological change. This study examines the self-view in personality disorders (PDs) and its change over the course of therapy using the Linguistic Inquiry and Word Count analysis procedure. A sample of 299 participants with PDs and 108 community control participants wrote short essays about their lives. Patients repeated the assignment three times over two years and completed assessments of PD-pathology, general psychopathology, PD-beliefs, and quality of life. Results show that as hypothesized the use of words in the 1st Person Singular Pronouns, Negative Emotion, Causation, Past and Future Tense Verbs categories significantly declines over the course of treatment, while the use of Present Tense Verbs and Positive Emotion increases. These categories tend to distinguish patients from non-patients prior to treatment. We also found 12 additional word categories changing over time, including Word Count and Negations. Change in word use statistically predicts better treatment outcome on all outcome measures (p < .001). Reductions in the use of Negative Emotion Words and Negations are the strongest predictors of outcome. The non-hypothesized role of Negations was explored and seemed to reflect that PD-patients miss a lot in their lives. Reduction of what they miss seems central to recovery. This issue seems relatively neglected in theoretical and treatment models of PDs. An increased focus on what patients miss in their lives might improve our understanding and treatment of PDs. In sum, Negative Emotion and Negation word categories appear to reflect key treatment targets.     

Asymmetric switch-costs and ERPs reveal facial identity dominance over expression

Previous studies on face processing have revealed an asymmetric overlap between identity and expression, as identity is processed irrespective of expression while expression processing partly depends on identity. To investigate whether this relative interaction is caused by dominance of identity over expression, participants performed familiarity and expression judgments during task switching. This paradigm reveals task-set dominance with a paradoxical asymmetric switch-cost (i.e., greater difference between switch and repeat trials when switching toward the dominant task). Event-related potentials (ERPs) were recorded to find the neural signature of the asymmetric cost. As expected, greater switch-cost was shown in the familiarity task with respect to response times, indicating its dominance over the expression task. Moreover, a left-sided ERP correlate of this effect was observed at the level of the frontal N2 component, interpreted as an index of modulations in endogenous executive control. Altogether, these results confirm the overlap between identity and expression during face processing and further indicate their relative dominance.     

Generalizing parametric models by introducing trial-by-trial parameter variability: The case of TVA

We identify two biases in the traditional use of Bundesen’s Theory of Visual Attention (TVA) and show that they can be substantially reduced by introducing trial-by-trial variability in the model. We analyze whole and partial report data from a comprehensive empirical study with 347 participants and elaborate on Bayesian model selection theory for quantifying the advantage of trial-by-trial generalization in general. The analysis provides strong evidence of trial-by-trial variation in both the VSTM capacity parameter and perceptual threshold parameter of TVA. On average, the VSTM capacity bias was found to be at least half an item, while the perceptual threshold parameter was found to be underestimated by about 2 ms.