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- Alaie, Iman
(författare)
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Adulthood Outcomes of Child and Adolescent Depression : From Mental Health to Social Functioning
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Depression is a common mental disorder affecting people across the lifespan, with first onset frequently occurring in the teenage years. The disorder is costly to society and constitutes one of the leading causes of disability in youths and adults worldwide. Research demonstrates that depression in childhood or adolescence is linked to adverse adult consequences, including mental health problems, physical health issues, various social difficulties, and economic hardships. While the specific factors and mechanisms associated with these long-term adversities are not well understood, previous studies point to the relevance of considering the heterogeneity in early-life depression.The overarching aim of this doctoral thesis was to shed more light on long-term outcomes of childhood and adolescent depression across multiple life domains. This work made use of extensive follow-up data gathered in Sweden and USA, as part of two community-based longitudinal cohort studies of depressed and nondepressed youths prospectively followed into adulthood. In the Uppsala Longitudinal Adolescent Depression Study, participants were interviewed around age 16 (n=631) and age 31 (n=409). Using linkage to nationwide population-based registries, participants were followed up around age 40 (n=576). In the Great Smoky Mountains Study, participants were interviewed at repeated occasions in childhood and adolescence (n=1,420), and at further follow-ups in adulthood extending up to age 30 (n=1,336).Findings from this work suggest that childhood/adolescent depression can have long-lasting associations with a broad spectrum of adverse outcomes. First, the risk of adult depression is known to be elevated among those exposed to depression in early life; however, depressed youths experiencing major conflicts with parents may be at an additionally increased risk of subsequent depression recurrence. Second, early-life depression was found to be associated with higher levels of adult psychiatric disorders, and also with worse health, criminal, and social functioning, even when accounting for a multitude of potential confounders. Third, early-life depression was predictive of poor labor market outcomes, especially for those with persistent depression. This link was partially mediated by the course of depression. Fourth, the welfare burden associated with early depression amounted to considerable public expenditures in adulthood, particularly for those with persistent depression or comorbid psychiatric conditions such as anxiety and disruptive behavior disorders.The adverse long-term consequences in the wake of early-life depression underscore the importance of prevention and treatment approaches that are both efficacious and cost-effective. Such targeted efforts may have the potential to avert later ill-health, impairment, and possibly also economic disadvantage.
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- Björk, Robert G., 1974, et al.
(författare)
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A Climate Change aspect on root dynamics and nitrogen partitioning in a tundra landscape
- 2005
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Ingår i: Sediment budgets and rates of sediment transfer across cold environments in Europe. 3rd Workshop of the ESF Network SEDIFLUX, Durham, UK, 15 – 19 December 2005..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Arctic Climate Impact Assessment (ACIA) recently reported that Arctic is rapidly changing due to Climate Change. Likewise, the mountains of Europe are going to experience large shifts in plant composition and 41-56% of the alpine species might be on the edge of extinction according to the 1st synthesis of the Global Observation Research Initiative in Alpine Environments (GLORIA). Although the tundra ecosystems are subjected to dramatical changes as a result of Climate Change, there is little knowledge of the effect on root dynamics and its implication on the nitrifying and denitrifying microbial community. Here, we compare nitrification enzyme activity (NEA) and denitrification enzyme activity (DEA) rates along an altitudinal gradient with the effects of climatic warming using Open Top Chambers (OTCs) in consideration with root dynamics and architecture. This study was conducted at Latnjajaure Field Station (LFS) located in the midalpine region in northern Sweden. LFS is the Swedish field site for the International Tundra Experiment (ITEX), established in 1993. This gives an opportunity to investigate long-term effects of climatic warming by OTCs and an altitudinal gradient (1000m to 1365m), both within a very small geographical range. The OTCs used at LFS increases the soil surface temperature by approximately 1.5ºC whereas air temperatures normally falls with 0.6ºC with every hundred meter of increased altitude. To analyse the NEA and DEA we used an anaerobic incubation technique, based on acetylene inhibition technique, resulting in N2O as the only end product, which then were analysed by gas chromatography. Soil cores were additionally sampled in the OTCs to study the effects of climatic warming on the root system. The specific root length, root length density and root biomass were determined for the different root fractions. The results from NEA and DEA contradict each other. The gradient study show decreased NEA and DEA rates with falling altitude, whereas the warming experiment show a slight non significant increase due to the temperature enhancement by OTCs. The preliminary results from the root sampling indicate that there is a plant community specific response in root architecture, which has an output on root biomass and particularly in the fraction of fine roots, although, climatic warming did not have any significant affect on the root biomass. The fact that altitudinal temperature decline did not reduce NEA and DEA rates might in part be explained of the variables measured here, although they are not conclusive.
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- Björk, Robert G., 1974, et al.
(författare)
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Nitrification and Denitrification Enzyme Activity: a successful tool in Arctic and Alpine soil ecology
- 2007
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Ingår i: The 14th ITEX workshop, Falls Creek, Victoria, Australia, 2–6 February 2007..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Nitrogen is consideration to be a limiting factor for plants and microbes in arctic and alpine ecosystems and the rates of mineralization, nitrification, and denitrifi¬cation are known to be generally low. However, Climate Change is expected to alter the nitrogen availability and dynamics and, as a consequence, affect plant community composition and production. The general consensus today is that increased temperature will lead to greater microbial activity and more plant-available nitrogen. Nevertheless, nitrification and denitrification are restricted by a number of environmental factors such as low tem¬perature and low pH. The C/N ratio and the water content of the soils also play an important role in determining the rates of nitrification and denitrification. Since 2002 microbial studies has been undertaken at Latnjajure, and comprise several microbial techniques, e.g. Nitrification Enzyme Activity (NEA), Denitrification Enzyme Activity (DEA), Phospholipid fatty acid analysis (PFLA), and Temperature Gradient Gel Electrophoresis (TGGE). These studies focuses on the interaction between plants and microbes along natural environmental gradients, both within plant communities and within the landscape, but also entails the OTCs used in the ITEX studies at Latnjajaure. Here we present the techniques NEA and DEA and give some brief results from how these have been successfully applied at Latnjajaure. In ecosystems with low nitrification activity, small amounts of NO3-/NO2- will be formed and it is thus difficult to measure low fluxes. However, NO3-/NO2- can be converted to N2O and then analysed by gas chromatography, whereby the detection limit is increased at least 1000 times compared to the spectroscopical technique. These techniques are referred to Nitrification (NEA) and Denitrification Enzyme Activity (DEA) and give a potential measure on the nitrification and denitrification rates, which goes back to the actual populations of nitrifiers and denitrifiers in the soil. For instance, NEA has been proved to better correlate with extractable NH4+ concentration than net nitrification does, and still after twelve weeks show a strong correlation with the initial extractable NH4+ concentration. Therefore, these variables, in particular NEA, have the advantage of being a much more stable variable than, for instance, extractable N concentrations and net nitrification, and NEA and DEA are therefore suitable when working in fringe environments with restricted logistics like the Latnjajaure catchment. NEA is measured using a two-step incubation technique; first by incubate the soil with a nutrient solution for 24 hours in darkness, at room temperature on a rotary shaker. Sub-samples are then withdrawn after a specified time schedule. The second step allows NO3- to be reduced to N2O by adding a modified denitrifying bacterium, Pseudomonas chlororaphis ATCC 43928, together with a carbon source. This strain of bacteria lacks the enzyme to reduce N2O to N2. The samples are then again incubated in darkness, at room temperature for 24 hours, and analysed by gas chromatography. This method was first used by Lensi et al. (1985, 1986), to study nitrification potentials in forest soils. Furthermore, the method has been developed for soils with low pH and small amounts of NO3- and the analysis makes the quantification without interference of organic matter, which makes it suitable for arctic and alpine ecosystems. To analyse DEA an anaerobic incubation technique is used, based on acetylene inhibition of the N2O-reductase resulting in N2O as the only end product. The soil sample is evacuated and flushed with N2. Thereafter acetylene is inserted to a final acetylene concentration of 10%, and the samples are shaken continuously and gas samples are withdrawn after a specified time schedule, which is then analysed by gas chromatography. This provides an estimate of the maximum concentration of functional denitrifying enzymes in the soil. Denitrifiers, in contrast to nitrifiers, are heterotrophs and can switch from using NO3- as an alternative electron acceptor to O2 under aerobic conditions. This makes other factors in the soil important determinants of DEA, e.g. availability of oxygen and C. Hence, the presence of denitrifiers is rarely a limitation for denitrification and they usually make up a reasonably large fraction of the soil bacteria. At Latnjajaure NEA shows a larger differentiation across plant communities than DEA. However, the spatial variability in the landscape, at the meso-scale, was in the same range in both variables and increased with altitude from 1000 to 1365 m a.s.l, particularly in heath plant communities. This result suggests that the decrease in mean annual temperature with altitude (0.6ºC with every one hundred meters) did not reduce nitrification and denitrification rates, as one might have expected. None of the other variable studied could explain the altitudinal increase in all cases, and the factors controlling the nitrification and denitrification rates seem to vary with the vegetation type. Furthermore, neither NEA nor DEA exhibited any changes between the ambient and warmed plots in the warming experiments. However, the warming experiment in the dry heath exhibited a change in root morphology via increased specific root length (SRL; m gDM-1) and specific root area (SRA; m2 kgDM -1). As both heterotrophic microbes and plants out-compete nitrifiers for NH4+, a change in root morphology, as seen in the warming experiment, may also explain the increased activity of nitrifying and denitrifying microbes with altitude.
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- Jonsson, Ulf, 1974-
(författare)
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Adolescents with Depression Grown up : Education, Intimate Relationships, Mental Health, and Personality
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Unipolar depression, estimated to be the leading contributor to burden of disease in middle- and high-income countries, often has an onset in adolescence. The disorder is associated with substantial role impairment and is highly recurrent. This raises questions about both subsequent mental health and social outcome. In order to shed light on this, a community sample of adolescents with depression and non-depressed peers was followed-up after 15 years. In 1991-93, first-year students in upper secondary school (age 16-17) in the town of Uppsala, Sweden, were screened for depression. Adolescents with positive screening and selected peers with negative screening (n=631 in total) were assessed regarding mental health, social situation, and personality. At around age 31, the participants were followed-up in both national registers (n=609) and personal interviews (n=409). Outcome regarding social factors, mental health, and personality was assessed. At follow-up, the former depressed adolescents had completed higher education to a lesser extent than the former non-depressed adolescents. The females with adolescent depression were also at increased risk of subsequent abortion, divorce, single parenthood, and partner violence. Characteristics associated with depression in adolescence (such as poor school performance and disruptive disorders) seemed to contribute to the poor outcome in the social domain. Regarding adult mental health, long-term depression in adolescence was associated with a particularly poor outcome. Compared to adolescents with shorter episodes of depression, those with long-term depression were more likely to report recurrent depression, suicidal ideation, and a range of other mental disorders in adulthood. Measures of personality traits related to neuroticism (a tendency towards negative emotionality) were elevated during ongoing depression and anxiety disorders, but were normalized with remission. However, repeated depressive episodes seemed to leave the individual more vulnerable to stress. It is now important to assess if early treatment can alter the poor outcome depicted in this thesis. Since social adversity, educational difficulties, and interpersonal problems accompany the depressive disorder from adolescence onward, it should also be investigated if interventions aimed at such contextual factors can prevent recurrence and improve quality of life.
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- Ssegonja, Richard
(författare)
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Effectiveness and cost-effectiveness of indicated preventive interventions for depression in adolescents : An application of health economics methods
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Unipolar depressive disorders are commonly encountered conditions in clinical practice with about 25% reporting their first episode during adolescence. Longitudinal studies show adolescent depression to be associated with an increased risk of mental illness in adulthood, healthcare usage, poor educational outcomes, unemployment, and dependency on welfare recipiency. Therefore, adolescent depression contributes a high disease burden and impinges a considerable financial strain on society’s limited resources.Several preventive interventions have been developed to prevent adolescent depression. Of these interventions, group-based cognitive behavioural therapy (GB-CBT) indicated preventive interventions for depression are well studied and accepted. However, evaluations of their effectiveness and cost effectiveness have yielded conflicting and incomplete results mainly due to methodological limitations.Therefore, the overarching aim of this thesis was to investigate the effectiveness and cost-effectiveness of GB-CBT indicated preventive interventions for depression in children and adolescents, and estimate the additional healthcare costs and welfare burden in early to mid-adulthood associated with adolescent depression.In study I, GB-CBT indicated preventive interventions for depression in children and adolescents were protective against developing a depressive disorder and also reduced depressive symptoms. The intervention relative effect was noted to decay over time. Study II revealed that adolescent depression was associated with considerable increased healthcare consumption in mid-adulthood compared to the non-depressed peers at a population level. This finding was more pronounced in females with persistent depressive disorder (PDD). Study III showed adolescent depression to be associated with all the forms of social transfer payments (welfare) especially in individuals with PDD and those with early comorbid psychopathologies.Study IV demonstrated that GB-CBT indicated preventive interventions for adolescent depression are not only effective but also have the potential to be cost-effective compared to leaving adolescents with subsyndromal depression unattended.Findings from studies II and III, emphasized the large financial burden to society in terms of additional healthcare costs and welfare expenditure associated with adolescent depression. Whereas, study I and IV bring forward the message that it is possible to change the course of subsyndromal depression by offering GB-CBT indicated preventive interventions to adolescents with subsyndromal depression. Such an initiative was not only cost-effective compared to not intervening, but also largely cost-saving. Therefore, GB-CBT indicated preventive interventions could be used as part of a stepped care program linking into more specialized care services. The results of this thesis will be useful in decision-making concerning the resource allocation related to adoption and implementation of such preventive measures.
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