Clinical and neuropsychological aspects of non-fatal self-harm in schizophrenia

Purpose To investigate demographic, clinical and neuropsychological aspects of self-harm in schizophrenia and identify which are independently predictive of and therefore the most relevant to clinical intervention. Subjects and methods Eighty-seven patients with schizophrenia were interviewed regarding substance misuse, depression, hopelessness, negative/positive symptoms and illness insight. Neuropsychological assessment included premorbid IQ, continuous performance test, cognitive-motor and trait impulsivity. A prospective three-month review of medical records was also undertaken. Results Fifty-nine patients (68%) reported past self-harm (including attempted suicide). Those with past self-harm, compared to those without, were significantly more likely to report depression, hopelessness, impulsivity, a family history of self-harm, polysubstance abuse and had higher premorbid IQ. Logistic regression revealed that depression, higher premorbid IQ and polysubstance abuse were independently linked to self-harm. Five participants attempted self-harm during the 3-month prospective follow-up period. These all had a history of past self-harm and were significantly more likely to have been depressed at the initial interview than those who did not go on to self-harm. Discussion and conclusions Independent predictors of self-harm in schizophrenia are premorbid IQ and polysubstance abuse. In addition, depression was both independently associated with past self-harm and predictive of self-harm in the follow-up period

Approaches to modelling land erodibility by wind

Land susceptibility to wind erosion is governed by complex multiscale interactions between soil erodibility and non-erodible roughness elements populating the land surface. Numerous wind erosion modelling systems have been developed to quantify soil loss and dust emissions at the field, regional and global scales. All of these models require some component that defines the susceptibility of the land surface to erosion, ie, land erodibility. The approaches taken to characterizing land erodibility have advanced through time, following developments in empirical and process-based research into erosion mechanics, and the growing availability of moderate to high-resolution spatial data that can be used as model inputs. Most importantly, the performance of individual models is highly dependent on the means by which soil erodibility and surface roughness effects are represented in their land erodibility characterizations. This paper presents a systematic review of a selection of wind erosion models developed over the last 50 years. The review evaluates how land erodibility has been modelled at different spatial and temporal scales, and in doing this the paper identifies concepts behind parameterizations of land erodibility, trends in model development, and recent progress in the representation of soil, vegetation and land management effects on the susceptibility of landscapes to wind erosion. The paper provides a synthesis of the capabilities of the models in assessing dynamic patterns of land erodibility change, and concludes by identifying key areas that require research attention to enhance our capacity to achieve this task