Divergent effects of first-generation and second-generation antipsychotics on cortical thickness in first episode psychosis

BACKGROUND: Whether there are differential effects of first-generation antipsychotics (FGAs) and second-generation antipsychotics (SGAs) on the brain is currently debated. Although some studies report that FGAs reduce grey matter more than SGAs, others do not, and research to date is limited by a focus on schizophrenia spectrum disorders. To address this limitation, this study investigated the effects of medication in patients being treated for first-episode schizophrenia or affective psychoses. METHOD: Cortical thickness was compared between 52 first-episode psychosis patients separated into diagnostic (i.e. schizophrenia or affective psychosis) and medication (i.e. FGA and SGA) subgroups. Patients in each group were also compared to age- and sex-matched healthy controls (n = 28). A whole-brain cortical thickness interaction analysis of medication and diagnosis was then performed. Correlations between cortical thickness with antipsychotic dose and psychotic symptoms were examined. RESULTS: The effects of medication and diagnosis did not interact, suggesting independent effects. Compared with controls, diagnostic differences were found in frontal, parietal and temporal regions. Decreased thickness in FGA-treated versus SGA-treated groups was found in a large frontoparietal region (p < 0.001, corrected). Comparisons with healthy controls revealed decreased cortical thickness in the FGA group whereas the SGA group showed increases in addition to decreases. In FGA-treated patients cortical thinning was associated with higher negative symptoms whereas increased cortical thickness in the SGA-treated group was associated with lower positive symptoms. CONCLUSIONS: Our results suggest that FGA and SGA treatments have divergent effects on cortical thickness during the first episode of psychosis that are independent from changes due to illness

Conversion to drip irrigated agriculture may offset historic anthropogenic and wildfire contributions to sediment production

This study is an investigation into the roles of wildfire and changing agricultural practices in controlling the inter-decadal scale trends of suspended sediment production from semi-arid mountainous rivers. In the test case, a decreasing trend in suspended sediment concentrations was found in the lower Salinas River, California between 1967 and 2011. Event to decadal scale patterns in sediment production in the Salinas River have been found to be largely controlled by antecedent hydrologic conditions. Decreasing suspended sediment concentrations over the last 15years of the record departed from those expected from climatic/hydrologic forcing. Sediment production from the mountainous headwaters of the central California Coast Ranges is known to be dominated by the interaction of wildfire and large rainfall/runoff events, including the Arroyo Seco, an ~700km(2) subbasin of the Salinas River. However, the decreasing trend in Salinas River suspended sediment concentrations run contrary to increases in the watershed's effective burn area over time. The sediment source area of the Salinas River is an order of magnitude larger than that of the Arroyo Seco, and includes a more complicated mosaic of land cover and land use. The departure from hydrologic forcings on suspended sediment concentration patterns was found to coincide with a rapid conversion of irrigation practices from sprinkler and furrow to subsurface drip irrigation. Changes in agricultural operations appear to have decreased sediment supply to the Salinas River over the late 20th to early 21st centuries, obscuring the influence of wildfire on suspended sediment production

Neurobiological and neuropsychological pathways into substance abuse and addictive behaviour

“Addiction,” derived from the Latin verb addicere (meaning “to enslave”), is characterized by the apparent “loss of control” or autonomy over one\u27s behavior. Indeed, the continued use of substances by addicted individuals, despite an apparent awareness of the adverse negative consequences, suggests that addictive behavior may involve deficits in inhibitory control, decision-making and the regulation of affect (Bechara et al., 2001; Fillmore, 2003; Goldstein & Volkow, 2002; Grant et al., 2000; Jentsch & Taylor, 1999; Lubman et al., 2004; Yücel & Lubman, 2007). Recent neuropsychological and neuroimaging studies across a variety of substance-using populations support this notion, implicating impairments in frontal cortical systems critically involved in executive control (Everitt et al., 2001; Rogers & Robbins, 2001). However, an important question that remains is why only a minority of individuals who experiment with addictive substances develop problematic substance-use patterns. This chapter explores this issue from a neuropsychological perspective, specifically focusing on the neuropsychological aspects of addictive behavior (including neuroimaging findings where relevant) under three main sections: (1) Neuropsychological sequelae of specific substances and their role in addictive behaviors. This section will briefly discuss the evidence for specific neuropsychological and neurobiological effects of several major classes of substances including alcohol, cannabis, inhalants, stimulants, opiates and ecstasy. The section ends with a summary of the major findings across the various substances, highlighting consistent evidence for problems in prefrontally mediated functions (such as inhibitory control, decision-making and affect regulation)

Evaluating treatment integrity in first episode early psychosis: Comparing what is promised with what is delivered

The experimental evaluation of multicomponent or 'complex' treatment models, such as first episode psychosis (FEP) intervention programs presents numerous methodological challenges

Fractionation of verbal memory impairment in schizophrenia and schizophreniform psychosis

Objectives: The characterization, aetiology, and course of verbal memory deficits in schizophrenia remain ill defined. The impact of antipsychotic medications is also unclear. The purpose of the present paper was to investigate verbal memory performance in established schizophrenia (SZ) and first-episode schizophreniform psychosis (FE). Method: Performances of 32 SZ and 33 FE patients were compared to those of 47 healthy volunteers on measures of verbal working memory, verbal associative learning and story recall. Results: Story recall deficits, but not deficits in working memory or paired associate learning, were demonstrated by both patient groups. Patients treated with typical neuroleptics had more impairment in associative learning with arbitrary word pairings than those treated with atypicals, regardless of patient group. Conclusions: The results are consistent with the notion that some neuropsychological impairment is present at the time of psychosis onset and that this impairment is non-progressive. However, deficits may be specific to subclasses of memory function.8 page(s