Obesity has limited behavioural overlap with addiction and psychiatric phenotypes

Anxiety disorders are the most prevalent mental disorders in developed countries. Obesity is hypothesized to be a risk factor for anxiety disorders but evidence supporting an association between these two conditions is not clear. The objectives of this paper were to systematically review the literature for a link between obesity and anxiety disorders in the general population, and to present a pooled estimate of association. We performed a systematic search for epidemiological articles reporting on obesity (explanatory variable) and anxiety disorders (outcome variable) in seven bibliographical databases. Two independent reviewers abstracted the data and assessed study quality. We found 16 studies (2 prospective and 14 cross-sectional) that met the selection criteria. Measures of effect from prospective data were mixed but cross-sectional evidence suggested a positive association between obesity and anxiety. The pooled odds ratio from cross-sectional studies was 1.4 (confidence interval: 1.2-1.6). Subgroup analyses revealed a positive association in men and women. Overall, a moderate level of evidence exists for a positive association between obesity and anxiety disorders. Questions remain regarding the role of obesity severity and subtypes of anxiety disorders. The causal relationship from obesity to anxiety disorders could not be inferred from current data; future etiologic studies are recommended.

Theory and research have suggested that the personality disorders contained within the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) can be understood as maladaptive variants of the personality traits included within the five-factor model (FFM). The current meta-analysis of FFM personality disorder research both replicated and extended the 2004 work of Saulsman and Page (The five-factor model and personality disorder empirical literature: A meta-analytic review. Clinical Psychology Review, 23, 1055-1085) through a facet level analysis that provides a more specific and nuanced description of each DSM-IV-TR personality disorder. The empirical FFM profiles generated for each personality disorder were generally congruent at the facet level with hypothesized FFM translations of the DSM-IV-TR personality disorders. However, notable exceptions to the hypotheses did occur and even some findings that were consistent with FFM theory could be said to be instrument specific.

Neuroticism's prospective association with common mental disorders (CMDs) has fueled the assumption that neuroticism is an independent etiologically informative risk factor. This vulnerability model postulates that neuroticism sets in motion processes that lead to CMDs. However, four other models seek to explain the association, including the spectrum model (manifestations of the same process), common cause model (shared determinants), state and scar models (CMD episode adds temporary/permanent neuroticism). To examine their validity we reviewed literature on confounding, operational overlap, stability and change, determinants, and treatment effects. None of the models is able to account for (virtually) all findings. The state and scar model cannot explain the prospective association. The spectrum model has some relevance, especially for internalizing disorders. Common causes are most important but the vulnerability model cannot be excluded although confounding of the prospective association by baseline symptoms and psychiatric history is substantial. In fact, some of the findings, such as interactions with stress and the small decay of neuroticism's effect over time, are consistent with the vulnerability model. We describe research designs that discriminate the remaining models and plea for deconstruction of neuroticism. Neuroticism is etiologically not informative yet but useful as an efficient marker of non-specified general risk.