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Background : Imbalance of glutamatergic neurotransmission has been proposed as a key mechanism underlying symptoms of schizophrenia. The neuropetide N-acetylaspartylglutamate (NAAG) modulates glutamate release. NAAG provides a component of the proton magnetic resonance spectrum (1H-MRS) in humans. The signal of NAAG, however, largely overlaps with its precursor and degrading product N-acetylaspartate (NAA) that by itself does not act in glutamatergic neurotransmission. Methods: We quantified NAAG and NAA separately from the 1H-MRS signal in 20 patients with schizophrenia and 20 healthy comparison subjects on a 3.0 Tesla MR scanner. The 1H-MRS voxels were positioned in the anterior cingulate cortex (ACC) and in the left frontal lobe. Psychopathological symptoms and cognitive performance were assessed. Results: In the ACC, the ratio NAAG/NAA was increased (P = .041) and NAAG was increased at a trend level (P = .066) in patients, while NAA was reduced (P = .030). NAA correlated with attention performance in patients (r = .64, P = .005) in the ACC. There was no group difference of NAAG, NAA, or NAAG/NAA in the frontal lobe but an inverse correlation of NAAG with negatives symptoms (Positive and Negative Symptoms Scale [PANSS] negative, r = −.58, P = .018) and with the total symptom score (PANSS total, r = −.50, P = .049). In addition, there was a positive correlation of frontal lobe NAAG (r = .53, P = .035) and NAAG/NAA (r = .54, P = .030) with episodic memory in patients. Conclusions: In this study, we present the first in vivo evidence for altered NAAG concentration in patients with schizophrenia.

In this paper, we construct a new basis for insider--outsider theory that acknowledges that insiders are typically easier to organise, so that they can delegate their bargaining decisions to a representative if they want to. We show that harassment or discrimination of new workers by the insider work force is neither individually rational nor needed to explain union formation or inefficient hiring decisions. However, we show that there is a strong tendency for overemployment. Unions tend to increase the efficiency of hiring decisions although union contracts will look like inducing underemployment.

Fighting collusion Regulation of communication between firms This paper is an attempt to create a coherent approach to the design of competition policy enforcement against collusion based on theoretical considerations, evidence from economic experiments, and case studies. I argue that collusion should primarily be fought indirectly by targeting types of communication between firms that are particularly likely to facilitate collusion. In particular, I identify types of communication which have high potential anti‐competitive effects but where it is unlikely that prohibiting communication will lead to efficiency losses. This analysis leads to some simple rules concerning communication between firms, which could also guide the development of competition rules for B2B electronic market places. — Kai-Uwe Kuhn

Patients with first-episode schizophrenia appear to respond to lower doses of neuroleptics, and to be more sensitive to developing extrapyramidal side-effects. The authors therefore compared in such patients the efficacy and extrapyramidal tolerability of comparatively low dosages of the atypical neuroleptic risperidone and of the conventional neuroleptic haloperidol. Risperidone was hypothesized to have better extrapyramidal tolerability and efficacy in treating negative symptoms. Patients were randomly assigned under double-blind conditions to receive risperidone (n=143) or haloperidol (n=146) for 8 wk. The primary efficacy criterion was the estimated difference in the mean change in the Positive and Negative Symptom Scale (PANSS) negative score between treatment groups; secondary efficacy criteria were changes on the PANSS total score and other PANSS subscores, and several other measures of psychopathology and general functioning. The primary tolerability criterion was the difference in baseline-adjusted occurrence rates of extrapyramidal side-effects measured with the Simpson-Angus Scale (SAS) compared between treatment groups. The main hypothesis was that risperidone would be superior in terms of improving negative symptoms and lowering the risk of extrapyramidal symptoms. Secondary tolerability criteria were the other extrapyramidal symptoms, measured with the Hillside Akathisia Scale (HAS) and the Abnormal Involuntary Movement Scale (AIMS). The average mean daily doses were 3.8 mg (s.d.=1.5) for risperidone and 3.7 mg (s.d.=1.5) for haloperidol. There were similar, significant improvements in both treatment groups in the primary and secondary efficacy criteria. At week 8 nearly all scores of extrapyramidal side-effects indicated a significantly higher prevalence of extrapyramidal side-effects with haloperidol than with risperidone [SAS: risperidone 36.5% of patients; haloperidol 51.5% of patients; likelihood ratio test, chi2(1)=7.8, p=0.005]. There were significantly fewer drop-outs [risperidone n=55, drop-out rate=38.5%; haloperidol n=79, drop-out rate=54.1%, chi2(1)=7.1, p=0.009] and a longer non-discontinuation time [risperidone: average of 50.8 d to drop-out; haloperidol: average of 44.0 d to drop-out; log rank test, chi2(1)=6.4, p=0.011] in the risperidone group. Risperidone and haloperidol appear to be equally effective in treating negative and other symptoms of first-episode schizophrenia. Risperidone has better extrapyramidal tolerability and treatment retention rate than the equivalent dose of haloperidol in these patients.

Accepted clinical evidence suggests superior efficacy of novel antipsychotics in the treatment of cognitive symptoms in schizophrenia. Whether this constitutes a primary drug effect or a secondary effect due to easing extrapyramidal side-effects or improving positive symptoms when converting from a first- to a second-generation neuroleptic is still open to debate. Long-term efficacy as well as differential drug effects on cognitive performance are also poorly documented. We therefore compared cognitive performance of olanzapine vs. clozapine treatment in a controlled, randomized, double-blind trial. Fifty-four patients were assessed following a 2- to 9-day washout and again after 4 and 26 wk of neuroleptic treatment. Patients were rated on the PANSS for psychopathological changes, extrapyramidal side-effects were assessed on the Simpson-Angus Scale, and cognitive performance was assessed with the Stroop, Wisconsin Card Sorting and the Tower of London tests. Schizophrenia symptoms, extrapyramidal side-effects and cognitive performance improved significantly in the course of either drug treatment. Stroop test performance and Tower of London planning time improved significantly over 26 wk compared to baseline and 4-wk follow-up assessment while Wisconsin Card Sorting and Tower of London execution time improved significantly after 4 wk with no further improvement after 26 wk. Improved executive function was not related to improving positive symptoms and easing extrapyramidal side-effects, thus indicative of a primary treatment effect of either antipsychotic. However, Stroop reaction time improved with olanzapine while clozapine had a stronger effect on improving negative symptoms, thus suggestive of a differential drug effect.