[Exploring the relationship between internalized stigma, insight and depression for inpatients with schizophrenia]. / Études des liens entre la stigmatisation intériorisée, l'insight et la dépression chez des personnes souffrant de schizophrénie.

BACKGROUND: Recent studies on insight in people with schizophrenia showed that insight level is linked with treatment compliance. Therefore, many therapies are aimed at increasing the insight level, such as psycho-education. However, insight level is also probably linked with depression level. So, improving insight is at risk of increasing the level of depression. Nevertheless, results on this topic are not consensual in the scientific literature. Presumably, this could be due to the concept of insight itself, although we could hypothesise that some confounding variables are implied in the interaction between insight and depression, such as internalized stigma. AIMS: to test the hypothesis that the relationship between insight and depression is mediated by internalized stigma in people with schizophrenia. METHOD: Sixty-two patients with schizophrenia (DSM-IV or ICD-10) recruited in mental health services in Île de France (75% male), aged 20 to 64 years (m=38.71, σ=0. 43), filled in questionnaires assessing internalized stigma (ISMI), depression (CDSS and BDI) and insight (SAIQ, Q8, IS), after giving their written informed consent. Correlations between insight, depression and different variables were made (Hypothesis 1). Then we ran multiple regressions and partial correlations to test the internalized stigma mediation (Hypothesis 2). RESULTS: Insight, internalized stigma and depression are statistically significantly correlated with each scales used (except Q8). Insight is correlated with depressed mood (correlations between IS and CDSS: r=0.27, P=0.04, and BDI, r=0.40, P=0.001). We also found negative correlations between SAIQ and CDSS (r=-0.35, P=0.005) and the BDI (r=-0.4265, P=0.000) which means that good insight is linked with depression. This result validates our hypothesis 1. The statistic tests reveal other complementary results: the association between insight and depression is mediated by the level of internalized stigma: when ISMI is controlled, the correlation between insight and depression decreased moderately with CDSS and with small intensity with SAIQ, but clearly. So, ISMI is probably a mediating variable between IS and BDI-CDSS. In conclusion, internalized stigma could be a mediating variable between insight and depression. This validates our second hypothesis. CONCLUSIONS: Our results suggest that the relationship between insight and depression is mediated by internalized stigma. Patients with good insight who internalize stigma seem to be more depressed than those who don't. This result could have important consequences in clinical practice: improving insight level should be completed by a specific attention to the level and evolution of internalized stigma to avoid increasing depression. Further studies need to be conducted to confirm these results.

Rheology and phase behavior of dense casein micelle dispersions.

Casein micelle dispersions have been concentrated through osmotic stress and examined through rheological experiments. In conditions where the casein micelles are separated from each other, i.e., below random-close packing, the dispersions have exactly the flow and dynamic properties of the polydisperse hard-sphere fluid, demonstrating that the micelles interact only through excluded volume effects in this regime. These interactions cause the viscosity and the elastic modulus to increase by three orders of magnitude approaching the concentration of random-close packing estimated at C(max) approximately 178 g/l. Above C(max), the dispersions progressively turn into "gels" (i.e., soft solids) as C increases, with elastic moduli G(') that are nearly frequency independent. In this second regime, the micelles deform and/or deswell as C increases, and the resistance to deformation results from the formation of bonds between micelles combined with the intrinsic mechanical resistance of the micelles. The variation in G(') with C is then very similar to that observed with concentrated emulsions where the resistance to deformation originates from a set of membranes that separate the droplets. As in the case of emulsions, the G(') values at high frequency are also nearly identical to the osmotic pressures required to compress the casein dispersions. The rheology of sodium caseinate dispersions in which the caseins are not structured into micelles is also reported. Such dispersions have the behavior of associative polymer solutions at all the concentrations investigated, further confirming the importance of structure in determining the rheological properties of casein micelle systems.

Deswelling and deformation of microgels in concentrated packings.

Increasing the particle density of a suspension of microgel colloids above the point of random-close packing, must involve deformations of the particle to accommodate the increase in volume fraction. By contrast to the isotropic osmotic deswelling of soft particles, the particle-particle contacts give rise to a non-homogeneous pressure, raising the question if these deformations occur through homogeneous deswelling or by the formation of facets. Here we aim to answer this question through a combination of imaging of individual microgels in dense packings and a simple model to describe the balance between shape versus volume changes. We find a transition from shape changes at low pressures to volume changes at high pressures, which can be explained qualitatively with our model. Whereas contact mechanics govern at low pressures giving rise to facets, osmotic effects govern at higher pressures, which leads to a more homogeneous deswelling. Our results show that both types of deformation play a large role in highly concentrated microgel suspensions and thus must be taken into account to arrive at an accurate description of the structure, dynamics and mechanics of concentrated suspensions of soft spheres.