Branched-chain amino acids linked to depression in young adults

Depression is a heterogeneous mental health problem affecting millions worldwide, but a majority of individuals with depression do not experience relief from initial treatments. Therefore, we need to improve our understanding of the biology of depression. Metabolomic approaches, especially untargeted ones, can suggest new hypotheses for further exploring biological mechanisms. Using the FinnTwin12 cohort, a longitudinal Finnish population-based twin cohort, with data collected in adolescence and young adulthood including 725 blood plasma samples, we investigated associations between depression and 11 low-molecular weight metabolites (amino acids and ketone bodies). In linear regression models with the metabolite (measured at age 22) as the dependent variable and depression ratings (measured at age 12, 14, 17, or 22 from multiple raters) as independent variables [adjusted first for age, sex, body mass index (BMI), and additional covariates (later)], we initially identified a significant negative association of valine with depression. Upon further analyses, valine remained significantly negatively associated with depression cross-sectionally and over time [meta-analysis beta = -13.86, 95% CI (-18.48 to -9.25)]. Analyses of the other branched-chain amino acids showed a significant negative association of leucine with depression [meta-analysis beta = -9.24, 95% CI (-14.53 to -3.95)], while no association was observed between isoleucine and depression [meta-analysis beta = -0.95, 95% CI (-6.00 to 4.11)]. These exploratory epidemiologic findings support further investigations into the role of branched-chain amino acids in depression.Peer reviewe

Perceived Occupational Noise Exposure and Depression in Young Finnish Adults

We investigated the association between perceived occupational noise exposure and depressive symptoms in young Finnish adults and whether noise sensitivity moderates this association. This study was based on an ongoing longitudinal twin study. We included those who had been working daily (n = 521) or weekly (n = 245) during the past 12 months (mean age 22.4, SD 0.7, 53% female). We asked about occupational noise exposure at age 22 and assessed depressive symptoms using the General Behavior Inventory (GBI) at age 17 and 22. Noise sensitivity and covariates were used in linear regression models. Perceived daily occupational noise exposure was associated, as a statistically independent main effect with depressive symptoms at age 22 (beta 1.19; 95% CI 0.09, 2.29) among all, and separately for females (beta 2.22; 95% CI 0.34, 4.09) but not males (beta 0.22; 95% CI −1.08, 1.52). Noise sensitivity was independently associated with depressive symptoms among all (beta 1.35; 95% CI 0.54, 2.17), and separately for males (beta 1.96; 95% CI 0.68, 3.24) but not females (beta 1.05; 95 % CI −0.04, 2.13). Noise sensitivity was independent of perceived occupational noise exposure. Pre-existing depressive symptoms at age 17 were predictive of perceived occupational noise exposure, suggesting complex interactions of noise and depression

Noise sensitivity and musical background

Noise sensitive individuals have a predisposition to attend to sounds and to perceive them negatively. Noise sensitivity predicts noise annoyance. The aim of this study was to investigate if noise sensitivity is associated with musical background. A total of 197 participants were recruited in Finland (N=91; 44 men, 47 women) and in Italy (N=106; 10 men, 96 women). The age range was from 19 to 56 years (M = 28.57, SD = 7.93 for Finland; M = 24.71, SD = 8.01 for Italy). We administered questionnaires and listening tests both online and in the laboratory, focusing on musical background. Noise sensitivity was studied using the Weinstein's Noise Sensitivity Scale administered online. The subjects were divided into 3 groups according to their musical experience. The groups were non-musicians (N = 103), amateur musicians (N = 44) and musicians (N = 50). Non-musicians, amateurs and musicians did not differ significantly from each other in noise sensitivity. This finding hence does not relate noise sensitivity with a history of long-term exposure to music. Copyright ©(2015) by EAA-NAG-ABAV, ISSN2226-5147 All rights reservedNon peer reviewe

A window into the brain mechanisms associated with noise sensitivity

Noise sensitive individuals are more likely to experience negative emotions from unwanted sounds and they show greater susceptibility to adverse effects of noise on health. Noise sensitivity does not originate from dysfunctions of the peripheral auditory system, and it is thus far unknown whether and how it relates to abnormalities of auditory processing in the central nervous system. We conducted a combined electroencephalography and magnetoencephalography (M/EEG) study to measure neural sound feature processing in the central auditory system in relation to the individual noise sensitivity. Our results show that high noise sensitivity is associated with altered sound feature encoding and attenuated discrimination of sound noisiness in the auditory cortex. This finding makes a step towards objective measures of noise sensitivity instead of self-evaluation questionnaires and the development of strategies to prevent negative effects of noise on the susceptible population

Neuroanatomical substrate of noise sensitivity

Recent functional studies suggest that noise sensitivity, a trait describing attitudes towards noise and predicting noise annoyance, is associated with altered processing in the central auditory system. In the present work, we examined whether noise sensitivity could be related to the structural anatomy of auditory and limbic brain areas. Anatomical MR brain images of 80 subjects were parcellated with FreeSurfer to measure grey matter volume, cortical thickness, cortical area and folding index of anatomical structures in the temporal lobe and insular cortex. The grey matter volume of amygdala and hippocampus was measured as well. According to our findings, noise sensitivity is associated with the grey matter volume in the selected structures. Among those, we propose and discuss particular areas, previously linked to auditory perceptual, emotional and interoceptive processing, in which larger grey matter volume seems to be related to higher noise sensitivity

Noise sensitivity and musical background

Noise sensitive individuals have a predisposition to attend to sounds and to perceive them negatively. Noise sensitivity predicts noise annoyance. The aim of this study was to investigate if noise sensitivity is associated with musical background. A total of 197 participants were recruited in Finland (N=91; 44 men, 47 women) and in Italy (N=106; 10 men, 96 women). The age range was from 19 to 56 years (M = 28.57, SD = 7.93 for Finland; M = 24.71, SD = 8.01 for Italy). We administered questionnaires and listening tests both online and in the laboratory, focusing on musical background. Noise sensitivity was studied using the Weinstein's Noise Sensitivity Scale administered online. The subjects were divided into 3 groups according to their musical experience. The groups were non-musicians (N = 103), amateur musicians (N = 44) and musicians (N = 50). Non-musicians, amateurs and musicians did not differ significantly from each other in noise sensitivity. This finding hence does not relate noise sensitivity with a history of long-term exposure to music