Reward processing in adolescents with social phobia and depression.

OBJECTIVE: Impaired reward processing has been found in individuals with anxiety, but also major depressive disorder (MDD). Here, we studied neural correlates of reward anticipation and processing in a sample of youth with severe social phobia and comorbid depression (SP/MDD) and investigated the specific contribution of SP and MDD symptoms. METHODS: 15 affected, unmedicated and 25 typically developing (TD) youth completed a monetary gambling task, which included a positive, negative and ambiguous reward condition. Event-related potentials representing cue processing (cue P300), reward anticipation (stimulus preceding negativity, SPN), reward sensitivity (feedback related negativity, FRN) and reward processing (reward P300) were analysed. RESULTS: Reduced amplitudes of the right hemispheric (r)SPN and reward P300 were observed in SP/MDD compared to TD. Within the SP/MDD group SP symptoms correlated with larger rSPN, and FRN amplitudes. MDD symptoms correlated with smaller rSPN and smaller FRN positive-negative difference wave. CONCLUSIONS: Reward anticipation and feedback processing are reduced in SP/MDD. Higher SP symptoms are associated with stronger neural activation during reward anticipation and reward sensitivity. Depressive symptoms are associated with decreased reward anticipation and sensitivity. Findings are in line with the theory of heightened vigilance in anxiety and blunted reward processing due to anhedonia in MDD. SIGNIFICANCE: The study results can inform behavioural interventions for SP and MDD.

Implicit assumptions and interpretation bias in youth with severe, chronic social phobia.

Interpretation bias and dysfunctional social assumptions are proposed to play a pivotal role in the development and maintenance of social phobia (SP), especially in youth. In this study, we aimed to investigate disorder-specific implicit assumptions of rejection and implicit interpretation bias in youth with severe, chronic SP and healthy controls (CG). Twenty-seven youth with SP in inpatient/day-care treatment (M age = 15.6 years, 74% female) and 24 healthy controls (M age = 15.7 years, 54% female) were included. The Implicit Association Test (IAT) and the Affect Misattribution Procedure (AMP) were completed to assess implicit assumptions and interpretation bias related to the processing of social and affective stimuli. No group differences were observed for the IAT controlling for depressive symptoms in the analyses. However, group differences were found regarding interpretation bias (p = .017, η2p = .137). Correlations between implicit scores and explicit questionnaire results were medium to large in the SP group (r =|.28| to |.54|, pall ≤ .05), but lower in the control group (r =|.04| to |.46|, pall ≤ .05). Our results confirm the finding of an interpretation bias in youth SP, especially regarding the implicit processing of faces, whereas implicit dysfunctional social assumptions of being rejected do not seem to be specific for SP. Future research should investigate the causal relationship of assumptions/interpretation bias and SP.

Impact of Storage Conditions on the Breast Milk Peptidome.

Human donor milk (HDM) provides appropriate nutrition and offers protective functions in preterm infants. The aim of the study is to examine the impact of different storage conditions on the stability of the human breast milk peptidome. HDM was directly frozen at -80 °C or stored at -20 °C (120 h), 4 °C (6 h), or room temperature (RT for 6 or 24 h). The milk peptidome was profiled by mass spectrometry after peptide collection by ultrafiltration. Profiling of the peptidome covered 3587 peptides corresponding to 212 proteins. The variance of the peptidome increased with storage temperature and time and varied for different peptides. The highest impact was observed when samples were stored at RT. Smaller but significant effects were still observed in samples stored at 4 °C, while samples showed highest similarity to those immediately frozen at -80 °C when stored at -20 °C. Peptide structures after storage at RT for 24 h point to the increased activity of thrombin and other proteases cleaving proteins at lysine/arginine. The results point to an ongoing protein degradation/peptide production by milk-derived proteases. They underline the need for immediate freezing of HDM at -20 °C or -80 °C to prevent degradation of peptides and enable reproducible investigation of prospectively collected samples.