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Background D-serine is an allosteric modulator of the brain N-methyl-D-aspartate (NMDA) receptor and a potential novel treatment of schizophrenia. Double-blind studies have been performed at 30 mg/kg/day (~2 g/day) with encouraging results, but no formal dose escalation studies have been performed. We describe the first evaluation of the efficacy and safety of D-serine at doses >30 mg/kg/day; a 4-week, open-label trial of adjunctive D-serine (30, 60 or 120 mg/kg/day). Methods 42 antipsychotic-stabilized patients with schizophrenia or schizoaffective disorder participated. PANSS was obtained bi-weekly and neuropsychological (MATRICS) was obtained pre- and post medication phase. The pharmacokinetics/pharmacodynamics (PK/PD), and safety of doses ≥30 mg/kg was also evaluated. Results Significant improvement in symptoms and neuropsychological measures was noted across doses. On the PANSS, improvement was observed for positive (p=0.006;d=0.46), negative (p<0.001;d=0.68), general (p=0.001;d=0.53), and total (p<0.0001;d=0.74) symptoms. On MATRICS, while only non-significant improvement was noted at 30 mg/kg, highly significant, large effect size improvement was noted on the composite score (p<0.01;d=1.0) for doses ≥60 mg/kg, leading to a significant dose-by-time interaction (p<0.01). In PK analyses, significant dose-dependent increases in plasma D-serine levels were seen during the study, predictive of significantly increased brain levels. Furthermore, increases in plasma levels correlated with improved symptomatic and neuropsychological function. Discussion These findings support double-blind investigation of D-serine at doses ≥60 mg/kg/d, and suggest effectiveness in treatment of both persistent symptoms and neurocognitive dysfunction.

Anxiety is a core human emotion but can become pathologically dysregulated. We used functional magnetic resonance imaging (fMRI) neurofeedback (NF) to noninvasively alter patterns of brain connectivity, as measured by resting-state fMRI, and to reduce contamination anxiety. Activity of a region of the orbitofrontal cortex associated with contamination anxiety was measured in real time and provided to subjects with significant but subclinical anxiety as a NF signal, permitting them to learn to modulate the target brain region. NF altered network connectivity of brain regions involved in anxiety regulation: subjects exhibited reduced resting-state connectivity in limbic circuitry and increased connectivity in the dorsolateral prefrontal cortex. NF has been shown to alter brain connectivity in other contexts, but it has been unclear whether these changes persist; critically, we observed changes in connectivity several days after the completion of NF training, demonstrating that such training can lead to lasting modifications of brain functional architecture. Training also increased subjects' control over contamination anxiety several days after the completion of NF training. Changes in resting-state connectivity in the target orbitofrontal region correlated with these improvements in anxiety. Matched subjects undergoing a sham feedback control task showed neither a reorganization of resting-state functional connectivity nor an improvement in anxiety. These data suggest that NF can enable enhanced control over anxiety by persistently reorganizing relevant brain networks and thus support the potential of NF as a clinically useful therapy.

Objective Most previous studies of the incidence of tardive dyskinesia with atypical compared to conventional antipsychotics have not had tardive dyskinesia as their primary focus. The current study aimed to compare the incidence of tardive dyskinesia with atypical vs. conventional antipsychotics using methods similar to those from a previous prospective cohort study at our site in the 1980s. Method 352 initially tardive dyskinesia-free psychiatric outpatients were examined for a new diagnosis of tardive dyskinesia every 6 months for up to 4 years at a community mental health center. At baseline, subjects were receiving conventional antipsychotics only (23%), atypicals only (64%), or both (14%). Only 26 subjects had never received conventional antipsychotics. Results Compared with subjects treated with conventional antipsychotics alone since the previous visit, the adjusted tardive dyskinesia incidence rate-ratio for subjects treated with atypical antipsychotics alone was 0.68 (95% confidence interval 0.29 to 1.64). The incidence and prevalence of tardive dyskinesia was similar to previous findings at this site in the 1980s. Conclusion The incidence of tardive dyskinesia with recent exposure to atypical antipsychotics alone was more similar to that for conventional antipsychotics than in most previous studies. Despite high penetration of atypical antipsychotics into clinical practice, the incidence and prevalence of tardive dyskinesia appeared relatively unchanged since the 1980s. Clinicians should continue to monitor for tardive dyskinesia, and researchers should continue to pursue efforts to treat or prevent it.

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