King's College London

About: King's College London is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Mental health. The organization has 43107 authors who have published 113125 publications receiving 4498103 citations. The organization is also known as: King's & KCL.

Causal association between cannabis and psychosis: examination of the evidence

Abstract: Background Controversy remains as to whether cannabis acts as a causal risk factor for schizophrenia or other functional psychotic illnesses. Aims To examine critically the evidence that cannabis causes psychosis using established criteria of causality. Method We identified five studies that included a well-defined sample drawn from population-based registers or cohorts and used prospective measures of cannabis use and adult psychosis. Results On an individual level, cannabis use confers an overall twofold increase in the relative risk for later schizophrenia. At the population level, elimination of cannabis use would reduce the incidence of schizophrenia by approximately 8%, assuming a causal relationship. Cannabis use appears to be neither a sufficient nor a necessary cause for psychosis. It is a component cause, part of a complex constellation of factors leading to psychosis. Conclusions Cases of psychotic disorder could be prevented by discouraging cannabis use among vulnerable youths. Research is needed to understand the mechanisms by which cannabis causes psychosis.

Responses of tundra plants to experimental warming:meta‐analysis of the international tundra experiment

Abstract: The International Tundra Experiment (ITEX) is a collaborative, multisite experiment using a common temperature manipulation to examine variability in species response across climatic and geographic gradients of tundra ecosystems. ITEX was designed specifically to examine variability in arctic and alpine species response to increased temperature. We compiled from one to four years of experimental data from 13 different ITEX sites and used meta-analysis to analyze responses of plant phenology, growth, and reproduction to experimental warming. Results indicate that key phenological events such as leaf bud burst and flowering occurred earlier in warmed plots throughout the study period; however, there was little impact on growth cessation at the end of the season. Quantitative measures of vegetative growth were greatest in warmed plots in the early years of the experiment, whereas reproductive effort and success increased in later years. A shift away from vegetative growth and toward reproductive effort and success in the fourth treatment year suggests a shift from the initial response to a secondary response. The change in vegetative response may be due to depletion of stored plant reserves, whereas the lag in reproductive response may be due to the formation of flower buds one to several seasons prior to flowering. Both vegetative and reproductive responses varied among life-forms; herbaceous forms had stronger and more consistent vegetative growth responses than did woody forms. The greater responsiveness of the herbaceous forms may be attributed to their more flexible morphology and to their relatively greater proportion of stored plant reserves. Finally, warmer, low arctic sites produced the strongest growth responses, but colder sites produced a greater reproductive response. Greater resource investment in vegetative growth may be a conservative strategy in the Low Arctic, where there is more competition for light, nutrients, or water, and there may be little opportunity for successful germination or seedling development. In contrast, in the High Arctic, heavy investment in producing seed under a higher temperature scenario may provide an opportunity for species to colonize patches of unvegetated ground. The observed differential response to warming suggests that the primary forces driving the response vary across climatic zones, functional groups, and through time.

Psychological treatments for chronic post-traumatic stress disorder : Systematic review and meta-analysis

Abstract: Background The relative efficacy of different psychological treatments for chronic post-traumatic stress disorder (PTSD) is unclear. Aims To determine the efficacy of specific psychological treatments for chronic PTSD. Method In a systematic review of randomised controlled trials, eligible studies were assessed against methodological quality criteria and data were extracted and analysed. Results Thirty-eight randomised controlled trials were included in the meta-analysis. Trauma-focused cognitive–behavioural therapy (TFCBT), eye movement desensitisation and reprocessing (EMDR), stress management and group cognitive–behavioural therapy improved PTSD symptoms more than waiting-list or usual care. There was inconclusive evidence regarding other therapies. There was no evidence of a difference in efficacy between TFCBT and EMDR but there was some evidence that TFCBT and EMDR were superior to stress management and other therapies, and that stress management was superior to other therapies. Conclusions The first-line psychological treatment for PTSD should be trauma-focused (TFCBT or EMDR).

Biogeography: An Ecological and Evolutionary Approach

Abstract: PrefaceIntroduction To BiogeographyBiodiversityPatterns Of DistributionCommunities And EcosystemsThe Source Of NoveltyPatterns In The PastPatterns Of Life TodayInterpreting The PastIce And ChangeThe Making Of TodayProjecting Into The FutureDrawing Lines In The WaterLife (And Death) On Islands