Positive Symptoms Of Schizophrenia Research Articles

Adjunctive second-generation antipsychotics for specific symptom domains of schizophrenia resistant to clozapine: A meta-analysis

A fair amount of subjects with schizophrenia do not respond to clozapine and are defined ‘ultra-resistant’. In this systematic review and meta-analysis, we tested the efficacy of adjunctive second-generation antipsychotics (SGAs) for main symptom domains (positive, negative, and depressive symptoms) in individuals with clozapine-resistant schizophrenia. We searched main electronic databases till December 2017. We included twelve double-blind, randomized, placebo-controlled trials (RCTs), evaluating the efficacy of SGAs for clozapine non/partial responders. We did not find any difference between SGAs and placebo (standardized mean difference, SMD = −0.21; p = 0.170; I2 = 68.0%) in improving positive symptoms. The effect size varied according to RCT duration (p = 0.025) and assessment methods (p = 0.016). Low-moderate effects of SGAs on both negative (SMD = −0.38; p = 0.005; I2 = 62.7%) and depressive symptoms (SMD = −0.35; p = 0.003; I2 = 4.9%), were estimated. In sum, our meta-analysis highlights the lack of efficacy of SGAs as add-on treatment for positive symptoms in clozapine-resistant schizophrenia. A small benefit of SGAs was estimated for both negative and depressive symptoms. Further RCTs are needed to establish efficacy and tolerability of SGAs or other augmentation strategies for different symptoms of clozapine-resistant schizophrenia.

Schizophrenia-related cognitive dysfunction in the Cyclin-D2 knockout mouse model of ventral hippocampal hyperactivity

Elevated activity at the output stage of the anterior hippocampus has been described as a physiological endophenotype of schizophrenia, and its development maps onto the transition from the prodromal to the psychotic state. Interventions that halt the spreading glutamatergic over-activity in this region and thereby the development of overt schizophrenia could be promising therapies. However, animal models with high construct validity to support such pre-clinical development are scarce. The Cyclin-D2 knockout (CD2-KO) mouse model shows a hippocampal parvalbumin-interneuron dysfunction, and its pattern of hippocampal over-activity shares similarities with that seen in prodromal patients. Conducting a comprehensive phenotyping of CD2-KO mice, we found that they displayed novelty-induced hyperlocomotion (a rodent correlate of positive symptoms of schizophrenia), that was largely resistant against D1- and D2-dopamine-receptor antagonism, but responsive to the mGluR2/3-agonist LY379268. In the negative symptom domain, CD2-KO mice showed transiently reduced sucrose-preference (anhedonia), but enhanced interaction with novel mice and objects, as well as normal nest building and incentive motivation. Also, unconditioned anxiety, perseveration, and motor-impulsivity were unaltered. However, in the cognitive domain, CD2-knockouts showed reduced executive function in assays of rule-shift and rule-reversal learning, and also an impairment in working memory, that was resistant against LY379268-treatment. In contrast, sustained attention and forms of spatial and object-related memory that are mediated by short-term habituation of stimulus-specific attention were intact. Our results suggest that CD2-KO mice are a valuable model in translational research targeted at the pharmacoresistant cognitive symptom domain in causal relation to hippocampal over-activity in the prodrome-to-psychosis transition.

Simultaneous activation of muscarinic and GABAB receptors as a bidirectional target for novel antipsychotics

Recent preclinical studies point to muscarinic and GABAB receptors as novel therapeutic targets for the treatment of schizophrenia. This study was aimed to assess the role of muscarinic and GABAB receptor interactions in animal models of schizophrenia, using positive allosteric modulators (PAMs) of GABAB receptor (GS39783), muscarinic M4 (VU0152100) and M5 (VU0238429) receptor, and partial allosteric agonist of M1 receptor (VU0357017).DOI-induced head twitches, social interaction and novel object recognition tests were used as the models of schizophrenia. Analyses of DOI-induced increases in sEPSCs (spontaneous excitatory postsynaptic currents) were performed as complementary experiments to the DOI-induced head twitch studies. Haloperidol-induced catalepsy and the rotarod test were used to examine the adverse effects of the drugs.All three activators of muscarinic receptors were active in DOI-induced head twitches. When administered together with GS39783 in subeffective doses, only the co-administration of VU0152100 and GS39783 was effective. The combination also reduced the frequency but not the amplitude of DOI-induced sEPSCs. Neither VU0357017 nor VU0238429 were active in social interaction test when given alone, and also the combination of VU0152100 and GS39783 failed to reverse MK-801-induced deficits observed in this test. All muscarinic activators when administered alone or in combination with GS39783 reversed the MK-801-induced disruption of memory in the novel object recognition test, and their actions were blocked by specific antagonists. None of the tested compounds or their combinations influenced the motor coordination of the animals. The compounds had no effect on haloperidol-induced catalepsy and did not induce catalepsy when administered alone. Pharmacokinetic analysis confirmed lack of possible drug-drug interactions after combined administration of GS39783 with VU0357017 or VU0152100; however, when the drug was co-administered with VU0238429 its ability to pass the blood-brain barrier slightly decreased, suggesting potential drug-drug interactions.Our data show that modulation of cholinergic and GABAergic systems can potentially be beneficial in the treatment of the positive and cognitive symptoms of schizophrenia without inducing the adverse effects typical for presently used antipsychotics.

The Use of Statins for Antipsychotic Augmentation in Schizophrenia: Examination of Meta-Analyses With Flawed Methods and Conclusions.

A very large number of psychopharmacologic agents have been trialed as antipsychotic augmentation strategies for the improvement of positive, negative, mood, cognitive, and other symptoms of schizophrenia; statins are one among these. Two very recent meta-analyses examined data on statin augmentation from 5 to 6 randomized controlled trials (RCTs) in the field. One meta-analysis found that statins were superior to placebo for the improvement of total scale and general psychopathology subscale scores on the Positive and Negative Syndrome Scale; statins were no better than placebo for positive and negative subscale outcomes. The other meta-analysis, in contrast, found that statins were superior to placebo for the improvement of positive and negative subscale scores but were no better than placebo for total scale and general psychopathology subscale outcomes. Both meta-analyses were associated with serious flaws such as the combination of studies conducted in contrasting stages of illness, the combination of change and endpoint scores in the same analysis, and the use of numbers that were prima facie incorrect. The first take-home message is that clinicians who read meta-analyses for guidance on how to better treat patients and researchers who read meta-analyses with a view to citing these in their papers both need to exercise due diligence to determine whether what they are reading is valid or flawed. Because this could be a difficult task, journal editors and reviewers need to take more care during manuscript screening and processing than they appear to be doing at present. The second take-home message is that the consideration of statin augmentation is based on very few RCTs and the differences between trial drug and placebo in these RCTs are mostly so small as to be clinically not worth considering.

Effects of the T-type calcium channel antagonist Z944 on paired associates learning and locomotor activity in rats treated with the NMDA receptor antagonist MK-801.

Currently available antipsychotics are unsatisfactory given their side effects and limited efficacy for the cognitive symptoms of schizophrenia. Many currently available drugs, such as haloperidol, are T-type calcium channel antagonists in addition to their well-established antagonism of dopamine D2 receptors. Thus, preclinical research into the effects of T-type calcium channel antagonists/blockers in behavioral assays related to schizophrenia may inform novel therapeutic strategies. We explored the effects of a recently developed highly selective T-type calcium channel antagonist, Z944 (2.5, 5.0, 10.0mg/kg), on the MK-801 (0.15mg/kg) model of acute psychosis. To examine the effects of Z944 on behaviors relevant to schizophrenia, we tested touchscreen-based paired associates learning given its relevance to the cognitive symptoms of the disorder and locomotor activity given its relevance to the positive symptoms. Acute treatment with Z944 failed to reverse the visuospatial associative memory impairments caused by MK-801 in paired associates learning. The highest dose of drug (10.0mg/kg) given alone produced subtle impairments on paired associates learning. In contrast, Z944 (5.0mg/kg) blocked the expected increase in locomotion following MK-801 treatment in a locomotor assay. These experiments provide support that Z944 may reduce behaviors relevant to positive symptoms of schizophrenia, although additional study of its effects on cognition is required. These findings and other research suggest T-type calcium channel antagonists may be an alternative to currently available antipsychotics with less serious side effects.

Brain responses to different types of salience in antipsychotic na\xefve first episode psychosis: An fMRI study

Abnormal salience processing has been suggested to contribute to the formation of positive psychotic symptoms in schizophrenia and related conditions. Previous research utilising reward learning or anticipation paradigms has demonstrated cortical and subcortical abnormalities in people with psychosis, specifically in the prefrontal cortex, the dopaminergic midbrain and the striatum. In these paradigms, reward prediction errors attribute motivational salience to stimuli. However, little is known about possible abnormalities across different forms of salience processing in psychosis patients, and whether any such abnormalities involve the dopaminergic midbrain. The aim of our study was, therefore, to investigate possible alterations in psychosis in neural activity in response to various forms of salience: novelty, negative emotion, targetness (task-driven salience) and rareness/deviance. We studied 14 antipsychotic naïve participants with first episode psychosis, and 37 healthy volunteers. During fMRI scanning, participants performed a visual oddball task containing these four forms of salience. Psychosis patients showed abnormally reduced signalling in the substantia nigra/ventral tegmental area (SN/VTA) for novelty, negative emotional salience and targetness; reduced striatal and occipital (lingual gyrus) signalling to novelty and negative emotional salience, reduced signalling in the amygdala, anterior cingulate cortex and parahippocamal gyrus to negative emotional salience, and reduced cerebellar signalling to novelty and negative emotional salience. Our results indicate alterations of several forms of salience processing in patients with psychosis in the midbrain SN/VTA, with additional subcortical and cortical regions also showing alterations in salience signalling, the exact pattern of alterations depending on the form of salience in question.

Psychological interventions to reduce positive symptoms in schizophrenia: systematic review and network meta-analysis.

Psychological treatments are increasingly regarded as useful interventions for schizophrenia. However, a comprehensive evaluation of the available evidence is lacking and the benefit of psychological interventions for patients with current positive symptoms is still debated. The present study aimed to evaluate the efficacy, acceptability and tolerability of psychological treatments for positive symptoms of schizophrenia by applying a network meta-analysis approach, that can integrate direct and indirect comparisons. We searched EMBASE, MEDLINE, PsycINFO, PubMed, BIOSIS, Cochrane Library, World Health Organization's International Clinical Trials Registry Platform and ClinicalTrials.gov for randomized controlled trials of psychological treatments for positive symptoms of schizophrenia, published up to January 10, 2018. We included studies on adults with a diagnosis of schizophrenia or a related disorder presenting positive symptoms. The primary outcome was change in positive symptoms measured with validated rating scales. We included 53 randomized controlled trials of seven psychological interventions, for a total of 4,068 participants receiving the psychological treatment as add-on to antipsychotics. On average, patients were moderately ill at baseline. The network meta-analysis showed that cognitive behavioural therapy (40 studies) reduced positive symptoms more than inactive control (standardized mean difference, SMD=-0.29; 95% CI: -0.55 to -0.03), treatment as usual (SMD=-0.30; 95% CI: -0.45 to -0.14) and supportive therapy (SMD=-0.47; 95% CI: -0.91 to -0.03). Cognitive behavioural therapy was associated with a higher dropout rate compared with treatment as usual (risk ratio, RR=0.74; 95% CI: 0.58 to 0.95). Confidence in the estimates ranged from moderate to very low. The other treatments contributed to the network with a lower number of studies. Results were overall consistent in sensitivity analyses controlling for several factors, including the role of researchers' allegiance and blinding of outcome assessor. Cognitive behavior therapy seems to be effective on positive symptoms in moderately ill patients with schizophrenia, with effect sizes in the lower to medium range, depending on the control condition.

Salience-Default Mode Functional Network Connectivity Linked to Positive and Negative Symptoms of Schizophrenia.

Schizophrenia is a complex, debilitating mental disorder characterized by wide-ranging symptoms including delusions, hallucinations (so-called positive symptoms), and impaired motor and speech/language production (so-called negative symptoms). Salience-monitoring theorists propose that abnormal functional communication between the salience network (SN) and default mode network (DMN) begets positive and negative symptoms of schizophrenia, yet prior studies have predominately reported links between disrupted SN/DMN functional communication and positive symptoms. It remains unclear whether disrupted SN/DMN functional communication explains (1) solely positive symptoms or (2) both positive and negative symptoms of schizophrenia. To address this question, we incorporate time-lag-shifted functional network connectivity (FNC) analyses that explored coherence of the resting-state functional magnetic resonance imaging signal of 3 networks (anterior DMN, posterior DMN, and SN) with fixed time lags introduced between network time series (1 TR = 2 s; 2 TR = 4 s). Multivariate linear regression analysis revealed that severity of disordered thought and attentional deficits were negatively associated with 2 TR-shifted FNC between anterior DMN and posterior DMN. Meanwhile, severity of flat affect and bizarre behavior were positively associated with 1 TR-shifted FNC between anterior DMN and SN. These results provide support favoring the hypothesis that lagged SN/DMN functional communication is associated with both positive and negative symptoms of schizophrenia.

Efficacy of cariprazine on negative symptoms in patients with acute schizophrenia: A post hoc analysis of pooled data

Although currently approved antipsychotics exert efficacy on positive symptoms of schizophrenia, treatments for negative symptoms remain a major unmet need. Post hoc analyses were used to investigate the possible efficacy of cariprazine in patients with moderate/severe negative symptoms of schizophrenia and no predominance of positive symptoms. Data were pooled from 2 randomized, double-blind, placebo- and active-controlled cariprazine studies in patients with acute schizophrenia (NCT00694707, NCT01104766). Analyses included data from a subset of patients with a Positive and Negative Syndrome Scale factor score for negative symptoms (PANSS-FSNS) ≥24, PANSS factor score for positive symptoms (PANSS-FSPS) ≤19, and scores of ≥4 on ≥2 of 3 PANSS items (blunted affect [N1], passive/apathetic social withdrawal [N4], lack of spontaneity/flow of conversation [N6]). Changes from baseline to week 6 in PANSS-FSNS were evaluated in the following treatment groups: placebo (n = 79), cariprazine 1.5–3 (n = 94) and 4.5–6 mg/d (n = 66), risperidone 4 mg/d (n = 34), or aripiprazole 10 mg/d (n = 44). Significant differences were observed versus placebo for cariprazine (1.5–3 mg/d, P = .0179; 4.5–6 mg/d, P = .0002) and risperidone (P = .0149), but not aripiprazole (P = .3265), and versus aripiprazole for cariprazine 4.5–6 mg/d (P = .0197). After adjusting for positive symptom changes, differences versus placebo remained statistically significant for cariprazine (1.5–3 mg/d, P = .0322; 4.5–6 mg/d, P = .0038) but not for risperidone (P = .2204). PANSS-FSNS response (≥20% reduction from baseline) rates were significantly higher with cariprazine (1.5–3 mg/d = 54.3%, P = .0194; 4.5–6 mg/d = 69.7%, P = .0001) than placebo (35.4%). In patients with acute schizophrenia and moderate/severe negative symptoms, cariprazine was associated with significantly greater improvement in negative symptoms compared with placebo and aripiprazole, warranting further exploration of the efficacy of cariprazine on negative symptoms.

Maternal immune activation in mid-late gestation alters amphetamine sensitivity and object recognition, but not other schizophrenia-related behaviours in adult rats

Maternal immune activation induced by Poly(I:C) administration is one of the most commonly used animal models of schizophrenia at present. Previous work from our team has demonstrated that some, but not all of the features often reported for maternal immune activation exposure in rodents can be observed in rats exposed to maternal immune activation at mid or late gestation. To determine whether previous findings in our laboratory were due to these time points simply being less sensitive neurodevelopmental periods for rats with regard to maternal immune activation effects, we aimed to investigate whether maternal immune activation at an often-reported sensitive period (mid-late gestation, day 14) resulted in more behavioural features reflective of face validity for schizophrenia. We examined the behavioural outcomes of mid-late maternal immune activation on a battery of behavioural tests aimed at assessing validity for positive, negative and cognitive symptoms of schizophrenia. We found that rats exposed to maternal immune activation, compared to controls, exhibited enhanced sensitivity to the locomotor-stimulating effects of amphetamine and reduced exploration of novel objects. These findings present a unique profile of effects, different to what has already been established for the same time point in rats, and different to what we had found at earlier and later time points. This work, among others in the literature, highlights the varying nature of models of maternal immune activation and we submit that it is essential for laboratories to characterise their models of maternal immune activation on behaviour rather than assuming that the effects from one laboratory apply in their own.

Cannabidiol Administered During Peri-Adolescence Prevents Behavioral Abnormalities in an Animal Model of Schizophrenia.

Schizophrenia is considered a debilitating neurodevelopmental psychiatric disorder and its pharmacotherapy remains problematic without recent major advances. The development of interventions able to prevent the emergence of schizophrenia would therefore represent an enormous progress. Here, we investigated whether treatment with cannabidiol (CBD – a compound of Cannabis sativa that presents an antipsychotic profile in animals and humans) during peri-adolescence would prevent schizophrenia-like behavioral abnormalities in an animal model of schizophrenia: the spontaneously hypertensive rat (SHR) strain. Wistar rats and SHRs were treated with vehicle or CBD from 30 to 60 post-natal days. In experiment 1, schizophrenia-like behaviors (locomotor activity, social interaction, prepulse inhibition of startle and contextual fear conditioning) were assessed on post-natal day 90. Side effects commonly associated with antipsychotic treatment were also evaluated: body weight gain and catalepsy throughout the treatment, and oral dyskinesia 48 h after treatment interruption and on post-natal day 90. In experiment 2, serum levels of triglycerides and glycemia were assessed on post-natal day 61. In experiment 3, levels of BDNF, monoamines, and their metabolites were evaluated on post-natal days 61 and 90 in the prefrontal cortex and striatum. Treatment with CBD prevented the emergence of SHRs’ hyperlocomotor activity (a model for the positive symptoms of schizophrenia) and deficits in prepulse inhibition of startle and contextual fear conditioning (cognitive impairments). CBD did not induce any of the potential motor or metabolic side effects evaluated. Treatment with CBD increased the prefrontal cortex 5-HIAA/serotonin ratio and the levels of 5-HIAA on post-natal days 61 and 90, respectively. Our data provide pre-clinical evidence for a safe and beneficial effect of peripubertal and treatment with CBD on preventing positive and cognitive symptoms of schizophrenia, and suggest the involvement of the serotoninergic system on this effect.

Autoimmunity and immune system dysregulation in schizophrenia: IgGs from sera of patients hydrolyze myelin basic protein.

Several different theories of schizophrenia (SCZ) were discussed; the causes of this disease are not yet clear. Using ELISA, it was shown that titers of autoantibodies against myelin basic protein (MBP) in SCZ patients are ~1.8-fold higher than in healthy individuals but 5.0-fold lower than in patients with multiple sclerosis. Several rigid criteria were checked to show that the MBP-hydrolyzing activity is an intrinsic property of SCZ IgGs. Approximately 82% electrophoretically homogeneous SCZ IgGs purified using several affinity sorbents including Sepharose with immobilized MBP hydrolyze specifically only MBP but not many other tested proteins. The average relative activity of IgGs from patients with negative symptoms was 2.5-fold higher than that of patients with positive symptoms of SCZ, and it increases with the duration of this pathology. It was shown that abzymes are the earliest statistically significant markers of many autoimmune pathologies. Our findings surmise that the immune systems of individual SCZ patients can generate a variety of anti-MBP abzymes with different catalytic properties, which can attack MBP of the myelin-proteolipid shell of axons. Therefore, autoimmune processes together with other mechanisms can play an important role in SCZ pathogenesis. MBP-hydrolyzing antibodies were previously detected in the blood of 80% to 90% of patients with systemic lupus erythematosus (SLE) and multiple sclerosis (MS). In addition, some similar neuropsychiatric indicators of disease common to SLE, MS, and SCZ were described in the literature. Thus, the destruction of the myelin sheath and the production of MBP-hydrolyzing antibodies can be a common phenomenon for some different diseases.

Experiences, attitudes, and perceptions of caregivers of individuals with treatment-resistant schizophrenia: a qualitative study

BackgroundTreatment-resistant schizophrenia (TRS) affects about one-third of individuals with schizophrenia. People with TRS do not experience sustained symptom relief and at the same time have the most severe disease-related disability and associated costs among individuals with severe mental disorders. Like caregivers of people with treatment-responsive schizophrenia, caregivers of individuals with TRS experience the disease burden along with their care recipients; however, for those providing care for individuals with TRS, the stress of the burden is unrelenting due to uncontrolled symptoms and a lack of effective treatment options. The objective of this study is to better understand the burden of TRS from the caregiver perspective and to explore their perception of available treatments.MethodsEight focus groups with non-professional, informal caregivers of individuals with TRS were conducted in 5 US locations. TRS was defined as failure of ≥2 antipsychotics and persistent moderate-to-severe positive symptoms of schizophrenia, per caregiver report.ResultsThe 27 caregivers reported an average of 37 h/week providing direct care, and 21 reported being on call “24/7.” Caregivers commonly reported that their care recipients exhibited symptoms of auditory hallucinations (89%), agitation/irritability/hostility (81%), suspiciousness (78%), tangentiality (74%), and cognitive impairment (74%); 70% of caregivers ranked suspiciousness/persecution as the most challenging symptom category. Caring for an individual with TRS impacted many caregivers’ finances, career prospects, social relationships, and sense of freedom. Additionally, multiple medication failures led to a sense of hopelessness for many caregivers.ConclusionsPersistent positive symptoms caused significant perceived burden, feelings of being overwhelmed and having no relief, and substantial negative impacts on caregivers’ emotional and physical health. To address these substantial unmet needs, policy makers should be aware of the need for practical, social, and emotional support for these caregivers and their families. Additionally, new treatment options for TRS should be developed.

Long-Term Effects of Iloperidone on Cerebral Serotonin and Adrenoceptor Subtypes

The atypical antipsychotic drug iloperidone has high affinity for a wide range of neurotransmitter receptors, including serotonin and adrenoceptors. We examined the long-term effects of multiple doses of iloperidone (0.5, 1.5, or 5mg/kg) on serotonin (5-HT) 5-HT1A, 5-HT2A receptor subtypes, and adrenoceptors α1 and α2 subtypes. Rats received daily intraperitoneal injections of different doses of iloperiodone or vehicle for 4weeks. Receptor autoradiography quantified the levels of 5-HT and adrenoceptors in medial prefrontal cortex (MPC), dorsolateral frontal cortex (DFC), caudate putamen (CPu), nucleus accumbens (NAc), and hippocampal CA1 (HIP-CA1) and CA3 (HIP-CA3) regions. Four weeks of iloperidone treatment significantly and dose-dependently increased 5-HT1A and decreased 5-HT2A receptors in the MPC and DFC. Higher doses of iloperidone (1.5 and 5mg/kg) increased 5-HT1A and decreased 5-HT2A receptors in HIP-CA1 and HIP-CA3 regions. In addition, repeated iloperidone treatment produced significant increases in α1- and α2-adrenoceptors in MPC, DFC, HIP-CA1, and HIP-CA3 regions. No changes in 5-HT and adrenoceptors were observed in other brain regions examined. These results suggest that long-term iloperidone treatment exerts region- and dose-specific effects on forebrain 5-HT and adrenoceptors, which may contribute to its therapeutic benefits in improving positive and negative symptoms of schizophrenia as well as maintaining a benign safety profile.

Positive symptoms and time perception in schizophrenia: A meta-analysis

Positive symptoms of schizophrenia may be related to distortions in time perception. To examine this issue, we conducted a meta-analysis to determine whether positive symptoms are associated with deficits in time processing performance. MEDLINE and Web of Science were searched from January 1980 through March 2017, and all related articles and their references were scrutinized to find relevant studies. Studies were selected if they included participants with a diagnosis of schizophrenia, and reported data from behavioral measures of interval timing (e.g. duration discrimination and temporal order judgement). The results indicated that positive symptoms of schizophrenia are related with overestimation of interval timing (i.e., acceleration of the “internal clock”), and suggest that time perception may be associated with psychosis.

Subunit-specific NMDAR antagonism dissociates schizophrenia subtype-relevant oscillopathies associated with frontal hypofunction and hippocampal hyperfunction

NMDAR antagonism alters mesolimbic, hippocampal, and cortical function, acutely reproducing the positive, cognitive, and negative symptoms of schizophrenia. These physiological and behavioral effects may depend differentially on NMDAR subtype- and region-specific effects. The dramatic electrophysiological signatures of NMDAR blockade in rodents include potentiated high frequency oscillations (HFOs, ∼140 Hz), likely generated in mesolimbic structures, and increased HFO phase-amplitude coupling (PAC), a phenomenon related to goal-directed behavior and dopaminergic tone. This study examined the impact of subtype-specific NMDAR antagonism on HFOs and PAC. We found that positive-symptom-associated NR2A-preferring antagonism (NVP-AAM077), but not NR2B-specific antagonism (Ro25-6985) or saline control, replicated increases in HFO power seen with nonspecific antagonism (MK-801). However, PAC following NR2A-preferring antagonism was distinct from all other conditions. While θ-HFO PAC was prominent or potentiated in other conditions, NVP-AAM077 increased δ-HFO PAC and decreased θ-HFO PAC. Furthermore, active wake epochs exhibiting narrowband frontal δ oscillations, and not broadband sleep-associated δ, selectively exhibited δ-HFO coupling, while paradoxical sleep epochs having a high CA1 θ to frontal δ ratio selectively exhibited θ-HFO coupling. Our results suggest: (1) NR2A-preferring antagonism induces oscillopathies reflecting frontal hyperfunction and hippocampal hypofunction; and (2) HFO PAC indexes cortical vs. hippocampal control of mesolimbic circuits.

Long-term effects of iloperidone on cerebral dopamine receptor subtypes.

The atypical antipsychotic drug iloperidone has high affinity for a wide range of neurotransmitter receptors, including dopaminergic (DA), serotonergic, and adrenergic receptors. We examined the long-term effects of multiple doses of iloperidone on DA D1 , D2 , D3 , and D4 receptor subtypes. Sprague-Dawley adult rats (n=8/group) received daily intraperitoneal injections of iloperiodone (0.5, 1, or 5mg/kg) or vehicle for 4 weeks. Receptor autoradiography quantified the levels of DA receptors in medial prefrontal cortex (MPC), dorsolateral frontal cortex (DFC), caudate putamen (CPu), nucleus accumbens (NAc), and hippocampus (HIP). Four weeks of iloperidone treatment at 5mg/kg significantly increased D1 receptors in NAc (36%) and CPu (38%). Iloperidone (1.5 and 5mg/kg) dose-dependently increased D2 receptors in MPC (37 and 47%) and HIP (32 and 40%). Only the high dose of iloperidone (5mg/kg) increased D2 receptors in NAc (39%) and CPu (38%). Repeated treatment with iloperidone (1.5 and 5mg/kg) increased D4 receptors in the NAc (39 and 78%), CPu (42 and 83%) and HIP (54 and 72%). The three doses of iloperidone failed to alter D3 receptors in the brain regions examined in this study. These results suggest that iloperidone exerts region- and dose-specific effects on forebrain DA receptor subtypes, which may contribute to its therapeutic benefits in improving the positive and negative symptoms of schizophrenia with minimal extrapyramidal side effects.

Mentalization and empathy as predictors of violence in schizophrenic patients: Comparison with nonviolent schizophrenic patients, violent controls and nonviolent controls

There are conflicting results concerning risk of violence in schizophrenia. Empathy and mentalization deficits are associated both with schizophrenia and violence, however, there are only a few studies with equivocal results concerning their relationship. 88 violent and nonviolent paranoid schizophrenic and violent and nonviolent control males in psychiatric, forensic psychiatric and correctional institutions completed the Ekman 60 Faces test, Faux Pas Recognition Test, Eysenck IVE test, Interpersonal Reactivity Index, and the Spielberger Anger Expression Scale. Data were analysed with ANOVA and logistic regression models. Significant group differences with a characteristic pattern were detected in mentalization, facial affect recognition, fear and anger recognition, interpersonal distress, and frequency of direction of anger expression. Predictors of violent behaviour were different in the schizophrenic and non-schizophrenic groups. Lack of major differences in empathy and mentalization between violent and nonviolent schizophrenia patients suggests that such deficits are core features of schizophrenia but do not determine emerging violence in this illness. Our results emphasise the importance of distinguishing between violence related to core positive symptoms of schizophrenia and that emerging from independent comorbid antisocial personality traits in order to identify targets for screening, detection, prevention and management of violence risk in different subpopulations of schizophrenia patients.

Albizia zygia root extract exhibits antipsychotic-like properties in murine models of schizophrenia

BackgroundThe root extract of Albizia zygia (DC.) J.F. Macbr. (Leguminosae) is used to manage mental disorders in African traditional medicine. However, its value, particularly, against negative and cognitive symptoms of schizophrenia have not been evaluated. AimThe aim of this study was to evaluate the antipsychotic properties of the hydroethanolic root extract of Albizia zygia (AZE) against positive, negative and cognitive symptoms of schizophrenia in animal models. Materials and methodsThe effects of AZE (30–300 mg kg−1) were evaluated against apomorphine-induced cage climbing as well as ketamine -induced hyperlocomotion, -enhanced immobility, -impaired social interaction and novel object recognition. The propensity of AZE to induce catalepsy and to attenuate haloperidol-induced catalepsy were also investigated. ResultsAZE 30–300 mg kg−1 significantly reduced apomorphine-induced climbing behaviour as well as ketamine-induced hyperlocomotion, immobility and object recognition deficits (at least P < 0.05). Moreover, the extract showed no cataleptic effect but significantly inhibited haloperidol-induced catalepsy at a dose of 30 mg kg−1 (P < 0.05). ConclusionThe root extract of Albizia zygia exhibited an antipsychotic-like activity in mice with potential to alleviate positive, negative and cognitive symptoms of schizophrenia.

Comparison of therapeutic effects of monotherapy of chlorpromazine, risperidone and their combination in newly diagnosed schizophrenic patients

Background: This study evaluates and compares how negative and positive symptoms of schizophrenia were influenced with monotherapy with a first-generation anti-psychotic medication (Chlorpromazine) and a second generation anti-psychotic medication (Risperidone) and by their combination, both of which are commonly used in clinical psychiatric practice.Methods: It was randomized, double-blind, controlled clinical study performed in Indian newly diagnosed schizophrenic patients in the Department of psychiatry from Feb 2003 to March 2004. Patients 18 (eighteen) patients aged 20 to 60 years diagnosed schizophrenics according to ICD-10 Criteria who visited in outpatient department of psychiatry during study period. Three groups of 6 Patient each, group-1 - was treated with oral Chlorpromazine 100 mg 12 hly, group -2 - was treated with oral Risperidone 2mg 12 hly group 3 -was treated with combination of oral Chlorpromazine 100mg 12 hly + oral Risperidone 2 mg 12 hly. How symptomatology in schizophrenic patients affected, is measured by applying various validated psychiatric scales like Brief psychiatric Rating Score (BPRS), Scale for assessment of positive symptom(SAPS), and Scale for Assessment of Negative Symptoms (SANS).Results: the study showed that the combination therapy of oral Chlorpromazine 100 mg 12 hly + Risperidone 2mg 12 hly had reduced the overall beneficial effects which were achieved with monotherapy of both the drugs.Conclusions: In this study, the therapeutic effects of combination of oral Chlorpromazine 100 mg 12 hly + Risperidone 2 mg 12 hly found to be reduced on positive symptoms and negative symptoms of schizophrenia, assessed on SAPS and SANS scoring scales when compared with beneficial effects which were achieved with monotherapy of both the drugs.