Olfaction is a Marker of Severity but Not Diagnosis in Anorexia Nervosa: a Systematic Review and Meta-Analysis.

Researchers have examined if olfaction is a sensitive biomarker of anorexia nervosa, but considerable heterogeneity across studies makes it difficult to reach a consensus. This review and meta-analysis sought to clarify if olfaction is altered in individuals with anorexia nervosa and explore potential moderators of olfaction in this population. We performed quantitative and qualitative analyses of olfactory function in individuals with anorexia nervosa compared with healthy controls. A random effect model was used to estimate pooled effect sizes, and meta-regression was conducted to identify potential moderators. We found that individuals with anorexia nervosa had largely intact olfactory function compared with healthy controls in terms of threshold (g = -0.09, 95% confidence interval [CI] (-0.65,0.47), p = 0.757), identification (g = -0.06, 95% CI (-0.32,0.20), p = 0.642), and overall olfactory function (g = -0.47, 95% CI (-1.02,0.07), p = 0.090). Discrimination was different from control (g = -0.51, 95% CI (-0.97,-0.05), p = 0.029). However, after sensitivity analysis, the pooled effect size was nonsignificant in discrimination. Olfactory sensitivity covaried with anorexia nervosa severity, body mass index (BMI) positively moderated olfactory threshold score (ß = 0.79, 95% CI (0.18,1.41), p = 0.020) in individuals with anorexia nervosa. Disease duration negatively moderated olfactory threshold score (ß = -0.21, 95% CI (-0.40,-0.03), p = 0.034). The results suggest that olfaction is not a sensitive marker of anorexia nervosa diagnosis, but olfactory sensitivity may be a useful indicator of anorexia nervosa severity.

Mindfulness and Suicide Risk in Undergraduates: Exploring the Mediating Effect of Alexithymia.

The present study was designed to examine the relationship between dispositional mindfulness and suicide risk in undergraduates, and it further explored the potential mediating role of alexithymia in this relationship. A total of 2,633 undergraduates completed the Mindful Attention Awareness Scale (MAAS), the Suicidal Behaviors Questionnaire - Revised (SBQ-R), and the 20-item Toronto Alexithymia Scale (TAS-20). The results indicate that mindfulness and suicide risk were negatively correlated, and alexithymia partially mediated the relationship between mindfulness and suicide risk only in the female undergraduates. Moreover, only the difficulty in identifying feelings (DIF) factor of alexithymia mediated the relationship between mindfulness and suicide risk in the female undergraduates. These findings contribute to the potential mechanism that explains the relationship between mindfulness and suicide risk. Furthermore, it is possible to implement mindfulness in the suicide intervention of alexithymic individuals.

Depressive symptoms, post-traumatic stress symptoms and suicide risk among graduate students: The mediating influence of emotional regulatory self-efficacy.

The current study was to examine the relationship among depressive symptoms, post-traumatic stress symptoms, emotion regulatory self-efficacy and suicide risk. A cross-sectional survey was conducted among 3257 graduate students from a medical college of China. Lifetime prevalence of suicidal ideation, plan and attempt were 25.7%, 1.6%, 1.1%, respectively, with one-year suicidal ideation showing at 6.3%. Structural equation modeling was employed to examine the relative contribution of depressive symptoms, post-traumatic stress symptoms and emotion regulatory self-efficacy on suicide risk. Structural equation model had a highly satisfactory fit [χ2 = 7.782, df = 4, p = 0.096; RMSEA = 0.021; CFI = 0.992; GFI = 0.997]. Post-traumatic stress symptoms had a direct effect and an indirect effect on suicide risk via emotion regulatory self-efficacy. Depressive symptoms also had a direct effect and an indirect effect on suicide risk via emotion regulatory self-efficacy. The depressive and post-traumatic stress symptoms increased the risk of suicide risk, but the variable of emotion regulatory self-efficacy would be served as a buffering factor, decreasing the risk of suicide. The interaction term of depressive symptoms and post-traumatic stress symptoms had a direct effect on suicide risk. A significant interactive effect of depressive and post-traumatic stress symptoms on suicide risk was found.