Mechanism of action of atypical antipsychotic drugs and the neurobiology of schizophrenia

Setting the beat of an internal clock: Effects of dexamphetamine on different interval ranges of temporal processing in healthy volunteers

Drug studies are powerful models to investigate the neuropharmacological mechanisms underlying temporal processing in humans. This study administered dexamphetamine to 24 healthy volunteers to investigate time perception at different time scales, along with contributions from working memory. Healthy volunteers were administered 0.45 mg/kg dexamphetamine or placebo in a double-blind, crossover, placebo-controlled design. Time perception was assessed using three experimental tasks: a time-discrimination task, which asked participants to determine whether a comparison interval (1200 ± 0, 50, 100, 150, 200 ms) was shorter or longer than a standard interval (1200 ms); a retrospective time estimation task, which required participants to verbally estimate time intervals (10, 30, 60, 90 and 120 s) retrospectively; and a prospective time-production task, where participants were required to prospectively monitor the passing of time (10, 30, 60, 90 and 120 s). Working memory was assessed with the backwards digit span. On the discrimination task, there was a change in the proportion of long-to-short responses and reaction times in the dexamphetamine condition (but no association with working memory), consistent with an increase in the speed of an internal pacemaker, and an overestimation of durations in the timing of shorter intervals. There was an interaction between dexamphetamine, working memory, and performance on the estimation and production tasks, whereby increasing digit span scores were associated with decreasing interval estimates and increased produced intervals in the placebo condition, but were associated with increased interval estimates and decreased produced intervals after dexamphetamine administration. These findings indicate that the dexamphetamine-induced increase in the speed of the internal pacemaker was modulated by the basal working memory capacity of each participant. These findings in healthy humans have important implications for the role of dopamine, and its contributions to timing deficits, in models of psychiatric disorders.

Еffects of Antipsychotics on Bone Mineral Density in Schizophrenia

Previous researches have shown that patients with schizophrenia who were using antipsychotics in their treatment developed changes in Bone Mineral Density and body composition, leading to osteoporosis and modifications in weight, skeletal muscle mass index and percent of fat tissue. Results of many studies suggested that the use of antipsychotic causes hyperprolactinemia and consequently lower bone mineral density values were observed. Further, antipsychotics increase food intake and have possible effects on metabolism, causing changes in weight, glucose level and lipid status, all of which can be a risk for developing metabolic syndrome and result in changing of bone mineral density. Antipsychotics change cytokine profi les in patients with schizophrenia and on the other hand the influence of T cells, B cells and inflammatory cytokines on osteoclasts and on osteoblasts was also established. In assessing the effects of antipsychotic on bone metabolism very important is to consider the duration of the treatment and clinical course of the disease, but undeniable effect is careless life style and inadequate physical activity that patients with schizophrenia have. Our attempt is to give an overview of the newest findings in this field, regarding the direct effects of antipsychotics on the bone metabolism, but also through prolactine elevation, metabolic and immune changes. Better understanding of the underlying mechanisms of schizophrenia and changes in bone mineral density could improve our clinical practice: affect to choice of the individually most appropriate antipsychotic, point to the need to monitor possible immunmetabolic changes during the treatment and improvement of the life quality of this vulnerable population.

Adverse reaction reports of neuroleptic malignant syndrome induced by atypical antipsychotic agents in the Japanese Adverse Drug Event Report (JADER) database

AIM

This study evaluates reports on neuroleptic malignant syndrome (NMS) as an adverse event associated with the use of atypical antipsychotic agents (AAA) in Japan. We examined NMS occurrence following monotherapy and combination therapy with AAA in real clinical practice using the Japanese Adverse Drug Event Report database.

METHODS

Adverse drug reaction reports associated with the use of one or more AAA or haloperidol were analyzed. The odds ratios of NMS occurrence after monotherapy and combination therapy with AAA without typical antipsychotic agents (TAA) relative to those after haloperidol monotherapy were estimated using multiple logistic regression.

RESULTS

Associated with the use of one or more AAA without TAA were 721 events of NMS in 11 071 cases. NMS occurrence after monotherapy with most AAA and their combinations had lower odds ratios than that after haloperidol use. However, the odds ratios after blonanserin monotherapy and combination therapies with quetiapine and zotepine, and risperidone and zotepine were estimated higher than 1.

CONCLUSION

Monotherapy or combination therapy with most AAA without TAA was not likely to cause NMS as an adverse reaction compared to haloperidol monotherapy. However, blonanserin monotherapy and combination therapies with quetiapine and zotepine, and risperidone and zotepine, possibly increase the report of NMS. Our results may provide useful information for medications such as AAA that are clinically used to treat mental disorders, though further research with more data are needed to clarify this.

Auditory verbal hallucinations in schizophrenia: current perspectives in brain stimulation treatments

PURPOSE

This review reports the current perspectives of brain stimulation techniques in the treatment of auditory verbal hallucinations (AVH) in schizophrenia.

METHODS

A systematic search of the literature in the PubMed database revealed that the most studied techniques are noninvasive techniques (NIBS), including electroconvulsive therapy (ECT), transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS).

RESULTS

The results showed that ECT could have great clinical efficacy but is currently underused in practice perhaps due to the costs associated with its limited implementation and potential associated risks. tDCS is still poorly studied and does not demonstrate sufficiently homogeneous or conclusive results yet to prove its efficacy in the treatment of AVH. However, its safe and simple implementation allows us to recommend it to patients who are refractory to other stimulation techniques. Finally, rTMS seems to be the most efficacious NIBS to offer patients with persistent AVH as an add-on therapeutic strategy. Its implementation has a non negligible cost but can be performed by a single practitioner. Great evolution in these techniques with technological progress, robotics and computer science are currently being tested and will undoubtedly improve the clinical efficacy of these procedures, particularly towards more personalized treatments such as individual rTMS targets and intensities. There are also new techniques for deep brain stimulation based on focused ultrasound that could provide much insight into the treatment of AVH in schizophrenia.

CONCLUSION

This review suggests that add-on brain stimulation treatments could play a key role among the therapeutic strategies for auditory hallucinations reduction in schizophrenia.

Effects of 5-HT7 receptor antagonists on behaviors of mice that detect drugs used in the treatment of anxiety, depression, or schizophrenia

5-HT₇ receptors have been suggested to play a role in the regulation of psychiatric disorders. The experimental literature however is not fully consistent on this possibility. Two selective 5-HT₇ receptor antagonists, DR-4004 and SB-269970, were evaluated in mouse models used to detect drugs used to treat anxiety, depression, or schizophrenia. A 5-HT-induced hypothermia assay was used to define the doses of DR-4004 and SB-269970 predicted to impact 5-HT₇ receptors in the brain in vivo. 5-HT produced hypothermia in wildtype mice by either i.p. or i.c.v. routes but did not in 5-HT₇ receptor knockout mice. 5-HT-induced hypothermia was not attenuated by drugs selectively blocking alpha1 or 5-HT_1A receptors. Doses of DR-4004 and SB-269970 that blocked 5-HT-induced hypothermia, did not display significant anxiolytic-like (elevated plus maze; vogel conflict) or antidepressant-like efficacy (tail-suspension test) in mouse models. These compounds did demonstrate some antipsychotic-like properties in the PCP-induced hyperactivity assay and anxiolytic/anti-stress effects in the stress-induced cGMP assay. Negative findings were substantiated by positive control drugs that were active in each assay system. We conclude that 5-HT-induced hypothermia can be used to estimate blockade of central 5-HT₇ receptors. Effects of DR-4004 and SB-269970 in animal models are generally consistent with the experimental literature that the evidence is mixed or not robust regarding the potential efficacy of 5-HT₇ receptor antagonism in the treatment of anxiety, depression, or schizophrenia.

Psychopharmacology: From serendipitous discoveries to rationale design, but what next?

Psychopharmacology really developed as a discipline from the mid-20th century with the discovery of a number of new classes of psychoactive drugs which could modify behaviour. These drugs were discovered as a consequence of clinical observations of patients, often being treated for other conditions. These serendipitous discoveries were the start of an era of drug development which has led to the antidepressants, antipsychotics, anxiolytics and mood stabilisers used today. Subsequent research focused on understanding why these drugs were effective, and used this information to develop a second generation of drugs that were more selective for their therapeutic targets, and therefore had reduced side effects and improved safety and tolerability. After a period of decline in new discoveries and withdrawal of the majority of the major pharmaceutical companies from active development programmes in psychiatry, new avenues are emerging fuelling renewed interest in this area.

Synthesis and Biological Evaluation of Fused Tricyclic Heterocycle Piperazine (Piperidine) Derivatives As Potential Multireceptor Atypical Antipsychotics

Herein, a novel series of multireceptor ligands was developed as polypharmacological antipsychotic agents using the designed multiple ligand approach between dopamine receptors and serotonin receptors. Among them, compound 47 possessed unique pharmacological features, exhibiting high affinities for D₂, D₃, 5-HT_1A, 5-HT_2A, and 5-HT₆ receptors and low efficacy at the off-target receptors (5-HT_2C, histamine H₁, and adrenergic α₁ receptor). Compound 47 showed dose-dependent inhibition of apomorphine- and MK-801-induced motor behavior, and the conditioned avoidance response with low cataleptic effect. Moreover, compound 47 resulted nonsignificantly serum prolactin levels and weight gain change compared with risperidone. Additionally, compound 47 possessed a favorable pharmacokinetic profile with oral bioavailability of 58.8% in rats. Furthermore, compound 47 displayed procognition properties in a novel object recognition task in rats. Taken together, compound 47 may constitute a novel class of atypical antipsychotic drugs for schizophrenia.

Effects of olanzapine and haloperidol on mTORC1 signaling, dendritic outgrowth, and synaptic proteins in rat primary hippocampal neurons under toxic conditions

Recent studies have demonstrated that antipsychotic drugs may activate mammalian target of rapamycin complex 1 (mTORC1) signaling in neurons. However, the relationship between mTORC1 signaling activation and currently prescribed antipsychotic drugs remains incompletely understood. The purpose of this study was to determine whether alterations in the level of mTORC1 signaling occur after rat primary hippocampal neurons are treated with olanzapine and haloperidol under toxic conditions. Additionally, we investigated whether these drugs affect dendritic outgrowth and synaptic protein expression through the mTORC1 signaling pathway. We measured changes in mTORC1-mediated and synaptic proteins by Western blotting assay under toxic conditions induced by B27 deprivation. Dendritic outgrowth was determined by a neurite assay. Olanzapine significantly increased the phosphorylated levels of mTORC1, its downstream effectors, and its upstream activators. The increased mTORC1 phosphorylation induced by olanzapine was significantly blocked by specific PI3K, MEK, or mTORC1 inhibitors. Olanzapine also increased dendritic outgrowth and synaptic proteins levels; all of these effects were blocked by rapamycin. However, haloperidol had none of these effects. We demonstrated that olanzapine, but not haloperidol, activated the mTORC1 signaling pathway and increased dendritic outgrowth and synaptic proteins by activating mTORC1 signaling in rat primary hippocampal neurons. These findings suggest that olanzapine affects neuroplasticity by activating mTORC1 signaling.

Abnormalities of fronto-subcortical pathways in schizophrenia and the differential impacts of antipsychotic treatment: a DTI-based tractography study

The fronto-striato-thalamic circuitry is a key network in patients with schizophrenia (SZPs). We use diffusion tensor imaging (DTI) to investigate the integrity of white matter (WM) pathways involved in this network in SZPs relative to healthy controls (HCs). We also evaluate the differential impact of chronic exposure to clozapine as well as other atypical and typical antipsychotics. 63 HCs and 41 SZPs were included. Of the SZPs, 16 were treated with clozapine (SZPsC), 17 with atypical antipsychotics (SZPsA), and 8 with typical antipsychotics (SZPsT). Three tracts were reconstructed in the left hemisphere using tractography: one fronto-subcortical tract, one prefronto-subcortical tract, and one prefronto-frontal tract. Diffusion parameters were individually extracted in each tract. SZPs exhibited lower integrity in both the fronto-subcortical and prefronto-subcortical tracts relative to HCs, and SZPsT showed altered integrity compared to SZPsC. There were no WM integrity differences in the prefronto-frontal tract between SZP groups or between SZPs and HCs. SZPs exhibit structural connectivity abnormalities in the prefronto-fronto-subcortical network that are specifically and differentially impacted by the type of antipsychotic treatment. Additional studies are needed to separate the contributions of clozapine-mediated neuroprotection, neurotoxicity related to typical antipsychotics, and the illness itself to observed differences.

Optimization of maintenance therapy of Risperidone with CYP2D6 genetic polymorphisms through an extended translational framework-based prediction of target occupancies/clinical outcomes

Risperidone, one of the second-generation antipsychotics, can efficiently target dopamine D₂ and serotonin 5-HT_2A receptors. There actually exists significant implication of CYP2D6 genetic polymorphisms on the metabolic kinetics of risperidone, little is known about the extent of CYP2D6 impacting human D2 and 5-HT2A receptor occupancies as well as the clinical efficacy and efficacy in schizophrenia treatment. Here we assessed the influences of CYP2D6 gene polymorphisms on human target occupancies/clinical outcomes and optimized the maintenance therapy of risperidone. A translational framework, previously developed using in vitro and in vivo information in rats, was used as the basis for integrating the effects of CYP2D6 genetic polymorphisms on target occupancies and clinical outcomes. D₂ occupancy as a biomarker was related to Positive and Negative Syndrome Scale (PANSS) response and Simpson-Angus Scale (SAS). The population approach was applied to characterize pharmacokinetic and pharmacodynamic (PK/PD) profiles of risperidone. Non-compartment analysis method was performed to calculate the steady state PK/PD parameters of both risperidone and 9-hydroxyrisperidone. The predictive power of this extended translational framework was determined by comparing the predictions of target occupancies and clinical outcomes with the reported human values of risperidone at clinically suggested dosage of 4.0 mg/day. This extended translational framework was adequately used to predict human target occupancies and clinical outcomes. At the steady state, D₂ ROs were 75.8%, 79.3% and 86.0% for CYP2D6 poor metabolizer (PM), intermediate metabolizer (IM) and extensive metabolizer (EM), respectively; 5-HT_2A ROs were 96.4%, 97.2% and 98.4% for CYP2D6 PM, IM and EM, respectively; PANSS changes from placebo were -5.3, -7.7 and -11.3 for CYP2D6 PM, IM and EM, respectively; SAS changes from placebo were 0.13, 0.15 and 0.18 for CYP2D6 PM, IM and EM, respectively. The predictions of human D₂, 5-HT_2A RO, PANSS and SAS changes for risperidone with CYP2D6 genetic polymorphisms were well in line with the reported values in clinic. 5.0, 4.0 and 2.5 mg/day were the equivalent dosages of risperidone for CYP2D6 PM, IM and EM, respectively. The optimized maintenance therapy of risperidone was provided through the Three-Step method and the dosage range was 2.5-5.0 mg/day for three CYP2D6 gene groups in the present study. Taken together, our findings demonstrate that this extended translational framework not only differentiates the effects of CYP2D6 genetic polymorphisms on target occupancies and clinical outcomes, but also constitutes a scientific basis to optimize the maintenance therapy of neuropsychiatric patients in clinic.

Antipsychotic-Associated Symptoms of Tourette Syndrome: A Systematic Review

BACKGROUND

Although antipsychotics are used to treat Tourette syndrome, there have been reports of paradoxical induction of tics by first- and second-generation antipsychotics.

OBJECTIVE

The objective of this systematic review was to better characterize tics as the potential adverse effect of antipsychotics.

METHODS

A literature search was performed, with no language restriction, using the MEDLINE, EMBASE, and PsycINFO databases for all publications up to January 2018. To be included, studies utilizing any study design had to meet the following criteria: (1) a temporal association of tics with antipsychotic use where tics emerged during treatment or after discontinuation and (2) no diagnosis of Tourette syndrome before tic emergence. More stringent criteria were used for individuals under 18 years of age that included (1) no personal or family history of primary tic disorder and either (2) tics occurring during antipsychotic treatment improved significantly upon discontinuation or dose reduction or (3) tics emerged after discontinuation of at least 3 months of antipsychotic treatment. Data were extracted according to: age, sex, diagnosis, personal history of motor symptoms or family history of tics, antipsychotic type and dose, treatment duration, types of symptoms emerged, treatment strategies, and follow-up. A Fisher's exact test was used to compare the occurrence of symptoms between first- and second-generation antipsychotic users.

RESULTS

The search identified 1290 articles, of which 92 full-text articles were assessed leading to the inclusion of 50 articles. Most of the included articles were case reports or series, involving a total of 60 cases. Thirty cases were associated with treatment with first-generation antipsychotics, 27 with second-generation antipsychotics, and three with a combination of first- and second-generation antipsychotics. Antipsychotics were being used to treat schizophrenia in 60% of the cases and other indications included developmental, behavioral, and mood or anxiety disorders. Tics occurred during treatment (n = 44) or following treatment discontinuation (n = 16). The occurrence of vocal tics with or without motor tics was significantly higher in the first- vs. second-generation antipsychotic users (p < 0.0001). Significantly higher occurrences were also noted in the first- vs. second-generation antipsychotic users for specific types of vocal tics (i.e., barking and coprolalia) and other concurrent motor symptoms (i.e., tardive dyskinesia). In the cases identified, antipsychotic-associated tics were treated by (1) discontinuing the offending antipsychotic, reducing its dose, or switching to different antipsychotics for tics occurring during treatment, (2) reinitiating antipsychotic treatment for tics occurring following discontinuation, or (3) using non-antipsychotic agents. It should be noted that symptoms were not always fully reversible and recurred at times.

CONCLUSION

Tics can be a disturbing adverse effect of antipsychotics. Clinicians need to be particularly vigilant when initiating and modifying antipsychotic regimens.

Effects of 12-month, double-blind N-acetyl cysteine on symptoms, cognition and brain morphology in early phase schizophrenia spectrum disorders

BACKGROUND

Currently approved medications for schizophrenia are relatively ineffective for negative symptoms and cognitive impairment. N-Acetyl Cysteine (NAC) is a neuroprotective agent that improved general symptoms, cognitive impairment and negative symptoms in some but not all studies, but failed to improve positive symptoms in patients with schizophrenia. Progressive brain mass loss (PBML) has been consistently observed in early phase schizophrenia. NAC mitigates the deleterious effects oxidative stress, inflammation and glutamatergic excitotoxicity and these three pathological processes are hypothesized to contribute to PBML.

METHODS

In this study, we assessed the effects NAC (3600mg/day) in a 52-week, double-blind, placebo controlled trial on symptoms, and cognition in early phase schizophrenia spectrum disorders (N=60). In the context of the clinical trial, we explored the effects of NAC on brain morphology.

RESULTS

NAC significantly improved (time×group) PANSS total (F=14.7, p<0.001), negative (F=5.1, p=0.024) and disorganized thought (F=13.7, p<0.001) symptom scores. NAC failed to improve PANSS positive symptoms and BACS cognitive scores. In preliminary analyses, baseline right (r=-0.48, p=0.041) and left (r=-0.45, p=0.018) total cortical thickness, and thickness in other cortical regions, were associated with NAC related improvement in PANSS total scores, but NAC, as compared to placebo, did not significantly impact brain morphology over the study treatment period.

CONCLUSIONS

These results replicate some but not all previous findings of NAC efficacy. Preliminary results suggest that NAC's symptom effects may be related to structural integrity, but NAC failed to demonstrate treatment effects on longitudinal measures of brain morphology. ClinicalTrials.gov Identifier: NCT01339858.

Olanzapine - Focus on the Cardiometabolic Side Effects

In this article, we review the recent findings concerning weight gain, diabetes mellitus (DM), hyperlipidemia, cardiovascular side effects in patients receiving olanzapine. It will consider the OLZ is associated with an increase in metabolic syndrome or cardiovascular events, and knowledge of these risks is crucial for further monitoring of patients with OLZ-treatment. Although it is one of the most commonly prescribed and effective AATPs, olanzapine causes the most weight gain and metabolic impairments in humans. As noted with glucose abnormalities and antipsychotics, olanzapine has the greatest propensity for causing proatherogenic hyperlipidemia. The mechanism of dyslipidemia with OLZ is poorly understood, but OLZ has been shown to increase lipogenesis, reduce lipolysis, and enhance the antilipolytic effects of insulin in adipocytes. Olanzapine can induce cardiomyopathy in selected patients.

Taken together, all mentioned data indicate that interventions aimed at the amelioration of obesity and cardiovascular illness need to be as multipronged and complex as the contributing psychosocial, behavioural, and biological factors that make obesity and cardiovascular illness more likely in patients with severe mental illness, including schizophrenia.

Case Report and Review of the Literature: Cardiomyopathy in a Young Woman on High-Dose Quetiapine

We describe a case of cardiomyopathy due to quetiapine. Atypical antipsychotics are known for their multiple and sometimes dangerous side effects. Various studies showed increased sudden cardiac death and sudden unexpected deaths. Quetiapine can cause tachycardia and QT prolongation, alongside a broad list of other side effects. Cardiomyopathy has been reported, but a causative relation was doubted. We report a case of a 37-year-old woman developing a cardiomyopathy under high doses of quetiapine. Symptoms and ultrasound signs largely recovered in the course of the next months after quetiapine was stopped.

Pimping up Drugs Recovered, Superannuated and Under Exploited Drugs - An Introduction to the Basics of Drug Reprofiling

Drug development has moved along way forward from the days of with doctors peddling cauldrons of herbs and spices, however, the process can still miss opportunities for full exploitation of a drug’s potential. Drug reprofiling provides a chance for an established or a forgotten drug to move into a new area of therapy, whether related to the known effects or in a completely new area. In an era of environmental awareness and spiraling costs for traditional drug development, a strategy to squeeze every benefit out of drugs with known safety, tolerability and pharmacological parameters must be a strategically sound desire. We explore examples of success in reprofiling, draw comparisons between techniques, and finally provide two examples from the Valirx plc development pipeline currently undergoing the process.

d-Serine administration affects nitric oxide synthase 1 adaptor protein and DISC1 expression in sex-specific manner

Antipsychotic medications are inefficient at treating symptoms of schizophrenia (SCZ), and N-methyl d-aspartate receptor (NMDAR) agonists are potential therapeutic alternatives. As such, these agonists may act on different pathways and proteins altered in the brains of patients with SCZ than do antipsychotic medications. Here, we investigate the effects of administration of the antipsychotic haloperidol and NMDAR agonist d-serine on function and expression of three proteins that play significant roles in SCZ: nitric oxide synthase 1 adaptor protein (NOS1AP), dopamine D2 (D2) receptor, and disrupted in schizophrenia 1 (DISC1). We administered haloperidol or d-serine to male and female Sprague Dawley rats via intraperitoneal injection for 12 days and subsequently examined cortical expression of NOS1AP, D2 receptor, and DISC1. We found sex-specific effects of haloperidol and d-serine treatment on the expression of these proteins. Haloperidol significantly reduced expression of D2 receptor in male, but not female, rats. Conversely, d-serine reduced expression of NOS1AP in male rats and did not affect D2 receptor expression. d-serine treatment also reduced expression of DISC1 in male rats and increased DISC1 expression in female rats. As NOS1AP is overexpressed in the cortex of patients with SCZ and negatively regulates NMDAR signaling, we subsequently examined whether treatment with antipsychotics or NMDAR agonists can reverse the detrimental effects of NOS1AP overexpression in vitro as previously reported by our group. NOS1AP overexpression promotes reduced dendrite branching in vitro, and as such, we treated cortical neurons overexpressing NOS1AP with different antipsychotics (haloperidol, clozapine, fluphenazine) or d-serine for 24 h and determined the effects of these drugs on NOS1AP expression and dendrite branching. While antipsychotics did not affect NOS1AP protein expression or dendrite branching in vitro, d-serine reduced NOS1AP expression and rescued NOS1AP-mediated reductions in dendrite branching. Taken together, our data suggest that d-serine influences the function and expression of NOS1AP, D2 receptor, and DISC1 in a sex-specific manner and reverses the effects of NOS1AP overexpression on dendrite morphology.

Effects of prophylactic anticholinergic medications to decrease extrapyramidal side effects in patients taking acute antiemetic drugs: a systematic review and meta-analysis

OBJECTIVES

To determine the effectiveness of prophylactic anticholinergic medications in reducing extrapyramidal symptoms in patients taking acute antiemetics with a dopamine D2 receptor antagonist effect.

METHODS

Systematic searches of all published studies through March 2017 were identified from PubMed, Cochrane library, Embase, Web of Science and Scopus. Only randomised controlled trials of patients receiving dopamine D2 antagonist antiemetic therapy for acute migraine in which an anticholinergic or placebo was compared were included. Pooled ORs were calculated for incidence of extrapyramidal symptoms and sedation.

RESULTS

Four placebo-controlled randomised controlled trials consisting of 737 patients met the inclusion criteria for our meta-analysis. The effect of diphenhydramine differed depending on the method of administration of the antiemetic. When the antiemetic was delivered as a 2 min antiemetic bolus, the odds of extrapyramidal symptoms were significantly reduced in the diphenhydramine group compared with placebo (OR 0.42; 95% CI 0.22 to 0.81; P=0.01). However, when the antiemetic was given as a 15 min infusion, there was no significant difference in extrapyramidal symptoms with or without diphenhydramine (OR 1.06; 95% CI 0.58 to 1.91; P=0.85). The lowest incidence of extrapyramidal symptoms was observed in patients receiving a 15 min antiemetic infusion without diphenhydramine prophylaxis (9.8%). In two trials including 351 patients that dichotomously reported sedation scales, diphenhydramine had significantly higher rates of sedation (31.6%vs19.2%, OR 2.01, 95% CI 1.21 to 3.33; P=0.007).

CONCLUSION

Prophylactic diphenhydramine reduces extrapyramidal symptoms in patients receiving bolus antiemetic therapy with a dopamine D2 antagonist effect, but not when it is given as an infusion. Because of significantly greater sedation with diphenhydramine, the most effective strategy is to administer the D2 antagonist antiemetic as a 15 min infusion without prophylaxis.

Revisiting the Therapeutic Potential of Bothrops jararaca Venom: Screening for Novel Activities Using Connectivity Mapping

Snake venoms are sources of molecules with proven and potential therapeutic applications. However, most activities assayed in venoms (or their components) are of hemorrhagic, hypotensive, edematogenic, neurotoxic or myotoxic natures. Thus, other relevant activities might remain unknown. Using functional genomics coupled to the connectivity map (C-map) approach, we undertook a wide range indirect search for biological activities within the venom of the South American pit viper Bothrops jararaca. For that effect, venom was incubated with human breast adenocarcinoma cell line (MCF7) followed by RNA extraction and gene expression analysis. A list of 90 differentially expressed genes was submitted to biosimilar drug discovery based on pattern recognition. Among the 100 highest-ranked positively correlated drugs, only the antihypertensive, antimicrobial (both antibiotic and antiparasitic), and antitumor classes had been previously reported for B. jararaca venom. The majority of drug classes identified were related to (1) antimicrobial activity; (2) treatment of neuropsychiatric illnesses (Parkinson’s disease, schizophrenia, depression, and epilepsy); (3) treatment of cardiovascular diseases, and (4) anti-inflammatory action. The C-map results also indicated that B. jararaca venom may have components that target G-protein-coupled receptors (muscarinic, serotonergic, histaminergic, dopaminergic, GABA, and adrenergic) and ion channels. Although validation experiments are still necessary, the C-map correlation to drugs with activities previously linked to snake venoms supports the efficacy of this strategy as a broad-spectrum approach for biological activity screening, and rekindles the snake venom-based search for new therapeutic agents.

Psilocybin disrupts sensory and higher order cognitive processing but not pre-attentive cognitive processing-study on P300 and mismatch negativity in healthy volunteers

RATIONALE

Disruption of auditory event-related evoked potentials (ERPs) P300 and mismatch negativity (MMN), electrophysiological markers of attentive and pre-attentive cognitive processing, is repeatedly described in psychosis and schizophrenia. Similar findings were observed in a glutamatergic model of psychosis, but the role of serotonergic 5-HT_2A receptors in information processing is less clear.

OBJECTIVES

We studied ERPs in a serotonergic model of psychosis, induced by psilocybin, a psychedelic with 5-HT_2A/C agonistic properties, in healthy volunteers.

METHODS

Twenty subjects (10M/10F) were given 0.26 mg/kg of psilocybin orally in a placebo-controlled, double-blind, cross-over design. ERPs (P300, MMN) were registered during the peak of intoxication. Correlations between measured electrophysiological variables and psilocin serum levels and neuropsychological effects were also analyzed.

RESULTS

Psilocybin induced robust psychedelic effects and psychotic-like symptoms, decreased P300 amplitude (p = 0.009) but did not affect the MMN. Psilocybin's disruptive effect on P300 correlated with the intensity of the psychedelic state, which was dependent on the psilocin serum levels. We also observed a decrease in N100 amplitude (p = 0.039) in the P300 paradigm and a negative correlation between P300 and MMN amplitude (p = 0.014).

CONCLUSIONS

Even though pre-attentive cognition (MMN) was not affected, processing at the early perceptual level (N100) and in higher-order cognition (P300) was significantly disrupted by psilocybin. Our results have implications for the role of 5-HT_2A receptors in altered information processing in psychosis and schizophrenia.

T4 and waist:hip ratio as biomarkers of antipsychotic-induced weight gain in Han Chinese inpatients with schizophrenia

Second-generation antipsychotic agents (SGAs) cause serious metabolic side effects, including weight gain, dyslipidemia, and glucose metabolism abnormalities, which occur by unknown mechanisms. Therefore, the search for prospective markers for antipsychotic-induced weight gain (AIWG) has been of major interest. So far, predictive factors predisposing patients to the develop obesity and related metabolic disturbances induced by SGAs have been relatively less studied among large samples of Chinese schizophrenic patients. In this study, 264 Han Chinese inpatients diagnosed with schizophrenia or schizoaffective disorder initiated treatment with olanzapine (n=131) or risperidone (n=133) and were followed for 12weeks. Anthropometric measurements and laboratory analyses of thyroid hormone, fasting plasma glucose (FPG), and lipid levels were conducted as part of routine medical care. The results showed baseline thyroxine (T4) and waist:hip ratio (WHR)were negatively correlated to AIWG (T4: rs=-0.154, P=0.014; WHR: rs=-0.199, P=0.008). Correlations remained significant after multiple regression analyses. The two treatment groups statistically differed for changes in body mass index, WHR, LDL cholesterol, and FPG; in both groups FPG decreased at first and then increased. Our findings suggest basal T4 and WHR may serve as early biomarkers for weight gain as a side effect of single-SGA treatment.

Synthesis and biological evaluation of a series of novel pyridinecarboxamides as potential multi-receptor antipsychotic drugs

In previous study, a series of benzamides was identified as potent antipsychotic agents. As a continuation of the program to discover novel antipsychotics, herein we reported the evaluation of a series of pyridinecarboxamide derivatives. The most promising compound 7h not only held good activities on dopamine D₂, serotonin 5-HT_1A and 5-HT_2A receptors, but also exhibited low potency for α_1A, H₁ and 5-HT_2C receptors, indicating a low propensity of side effects like orthostatic hypotension and weight gain. Furthermore, 7h exhibited more potent antipsychotic-like effect than aripiprazole in behavioral studies. The preliminary results were promising enough for further research around this scaffold.

Risperidone versus other antipsychotics for people with severe mental illness and co-occurring substance misuse

BACKGROUND

Up to 75% of people with serious mental illness (SMI) such as schizophrenia and bipolar disorder have co-occurring substance use disorders (dual diagnosis). Dual diagnosis can have an adverse effect on treatment and prognosis of SMI.

OBJECTIVES

To evaluate the effects of risperidone compared to treatment with other antipsychotics (first-generation and other second-generation antipsychotics) used in people with serious mental illness and co-occurring substance misuse.

SEARCH METHODS

On 6 January 2016 and 9 October 2017, we searched the Cochrane Schizophrenia Group's Study-Based Register of Trials (including trial registers).

SELECTION CRITERIA

We selected randomised trials of risperidone versus any other antipsychotic in people with SMI and substance abuse (dual diagnosis). We included trials meeting our inclusion criteria and reporting useable data. We excluded trials that either did not meet our inclusion criteria or met our inclusion criteria but did not report any useable data.

DATA COLLECTION AND ANALYSIS

We independently inspected citations and selected studies. For included studies, we independently extracted data and appraised study quality. For binary outcomes we calculated the risk ratios (RRs) and their 95% confidence intervals. For continuous outcomes we calculated the mean differences (MDs) and their 95% confidence intervals. We pooled data using random-effects meta-analyses and assessed the quality of evidence, creating a 'Summary of findings' table using the GRADE approach.

MAIN RESULTS

We identified eight randomised trials containing a total of 1073 participants with SMI and co-occurring substance misuse. Seven of these contributed useable data to the review. There was heterogeneity in trial design and measurement. Risperidone was compared to clozapine, olanzapine, perphenazine, quetiapine and ziprasidone. Few trials compared risperidone with first-generation agents. Few trials examined participants with a dual diagnosis from the outset and most trials only contained separate analyses of subgroups with a dual diagnosis or were secondary data analyses of subgroups of people with a dual diagnosis from existing larger trials.For risperidone versus clozapine we found no clear differences between these two antipsychotics in the reduction of positive psychotic symptoms (1 randomised controlled trial (RCT), n = 36, mean difference (MD) 0.90, 95% CI -2.21 to 4.01, very low quality evidence), or reduction in cannabis use (1 RCT, n = 14, risk ratio (RR) 1.00, 95% CI 0.30 to 3.35, very low quality evidence), improvement in subjective well-being (1 RCT, n = 36, MD -6.00, 95% CI -14.82 to 2.82, very low quality evidence), numbers discontinuing medication (1 RCT, n = 36, RR 4.05, 95% CI 0.21 to 78.76, very low quality evidence), extrapyramidal side-effects (2 RCTs, n = 50, RR 2.71, 95% CI 0.30 to 24.08; I² = 0%, very low quality evidence), or leaving the study early (2 RCTs, n = 45, RR 0.49, 95% CI 0.10 to 2.51; I² = 34%, very low quality evidence). Clozapine was associated with lower levels of craving for cannabis (1 RCT, n = 28, MD 7.00, 95% CI 2.37 to 11.63, very low quality evidence).For risperidone versus olanzapine we found no clear differences in the reduction of positive psychotic symptoms (1 RCT, n = 37, MD -1.50, 95% CI -3.82 to 0.82, very low quality evidence), reduction in cannabis use (1 RCT, n = 41, MD 0.40, 95% CI -4.72 to 5.52, very low quality evidence), craving for cannabis (1 RCT, n = 41, MD 5.00, 95% CI -4.86 to 14.86, very low quality evidence), parkinsonism (1 RCT, n = 16, MD -0.08, 95% CI -1.21 to 1.05, very low quality evidence), or leaving the study early (2 RCT, n = 77, RR 0.68, 95% CI 0.34 to 1.35; I² = 0%, very low quality evidence).For risperidone versus perphenazine, we found no clear differences in the number of participants leaving the study early (1 RCT, n = 281, RR 1.05, 95% CI 0.92 to 1.20, low-quality evidence).For risperidone versus quetiapine, we found no clear differences in the number of participants leaving the study early (1 RCT, n = 294, RR 0.96, 95% CI 0.86 to 1.07, low-quality evidence).For risperidone versus ziprasidone, we found no clear differences in the number of participants leaving the study early (1 RCT, n = 240, RR 0.96, 95% CI 0.85 to 1.10, low-quality evidence).For many comparisons, important outcomes were missing; and no data were reported in any study for metabolic disturbances, global impression of illness severity, quality of life or mortality.

AUTHORS' CONCLUSIONS

There is not sufficient good-quality evidence available to determine the effects of risperidone compared with other antipsychotics in people with a dual diagnosis. Few trials compared risperidone with first-generation agents, leading to limited applicability to settings where access to second-generation agents is limited, such as in low- and middle-income countries. Moreover, heterogeneity in trial design and measurement of outcomes precluded the use of many trials in our analyses. Future trials in this area need to be sufficiently powered but also need to conform to consistent methods in study population selection, use of measurement scales, definition of outcomes, and measures to counter risk of bias. Investigators should adhere to CONSORT guidelines in the reporting of results.

Synthesis and biological evaluation of a series of multi-target N-substituted cyclic imide derivatives with potential antipsychotic effect

In the present study, a series of multi-target N-substituted cyclic imide derivatives which possessed potent dopamine D₂, serotonin 5-HT_1A and 5-HT_2A receptors properties were synthesized and evaluated as potential antipsychotics. Among these compounds, (3aR,4R,7S,7aS)-2-(4-(4-(benzo[b]thiophen-4-yl)piperazin-1-yl)butyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione hydrochloride (3d) held a promising pharmacological profile. 3d not only showed potent and balanced in vitro activities on D₂/5-HT_1A/5-HT_2A receptors, but also endowed with low to moderate activities on 5-HT_2C, H₁, α_1A, M₃ receptors and hERG channel, suggesting a low liability to induce side effects such as weight gain, orthostatic hypotension and QT prolongation. In animal behavioral studies, 3d reduced phencyclidine-induced hyperlocomotion with a high threshold for catalepsy induction. Compound 3d was selected as a potential antipsychotic candidate for further development.

Cognitive function in schizophrenia: conflicting findings and future directions

INTRODUCTION

Schizophrenia is a severe mental disorder with multiple psychopathological domains being affected. Several lines of evidence indicate that cognitive impairment serves as the key component of schizophrenia psychopathology. Although there have been a multitude of cognitive studies in schizophrenia, there are many conflicting results. We reasoned that this could be due to individual differences among the patients (i.e. variation in the severity of positive vs. negative symptoms), different task designs, and/or the administration of different antipsychotics.

METHODS

We thus review existing data concentrating on these dimensions, specifically in relation to dopamine function. We focus on most commonly used cognitive domains: learning, working memory, and attention.

RESULTS

We found that the type of cognitive domain under investigation, medication state and type, and severity of positive and negative symptoms can explain the conflicting results in the literature.

CONCLUSIONS

This review points to future studies investigating individual differences among schizophrenia patients in order to reveal the exact relationship between cognitive function, clinical features, and antipsychotic treatment.

Long-lasting extrapyramidal symptoms after multiple injections of paliperidone palmitate to treat schizophrenia

PURPOSE

Antipsychotic drug treatment can potentially lead to adverse events such as extrapyramidal symptoms (EPSs). If these events persist, they lower patient quality of life. The purpose of this report is to present our experience with such a case, as an example to encourage further study.

PATIENTS AND METHODS

The patient was a 64-year-old male who had been diagnosed with schizophrenia that had been treated with oral antipsychotics for over 40 years. Due to lack of compliance, he was treated with the long-acting injectable antipsychotic, paliperidone palmitate, but developed persistent EPSs after 6 months. He was subsequently treated and monitored in our inpatient facility.

RESULTS

Antipsychotic treatment was stopped. After 6 weeks, the patient's psychosis had worsened, but his EPSs remained unchanged. Levodopa treatment was then started (up to 400 mg/d), which improved his EPSs, so he was restarted on oral antipsychotic therapy (aripiprazole, 6-18 mg/d). His psychotic symptoms improved over 2 months. The improvements in both psychosis and EPSs remained stable. Dopamine transporter scans revealed moderate dopamine transporter loss in the striatum, and computed tomography revealed no sign of brain abnormalities, suggesting that the patient was susceptible to dopamine reductions.

CONCLUSION

Paliperidone palmitate can induce EPSs, even if injected only a few times. Although the characteristics of the drug are potential causes, the patient's predisposition to dopamine perturbations can also influence the outcome. Therefore, adequate awareness is required before injection.

Antipsychotic medication and oropharyngeal dysphagia: systematic review

The association between antipsychotics (also known as neuroleptics) and oropharyngeal dysphagia (OD) has been suggested in several case reports. The purpose of this systematic review was to examine the effect of antipsychotic medication on OD. A systematic literature search was carried out according to PRISMA guidelines using the electronic databases Pubmed and Embase. In Pubmed, we used the MeSH terms 'antipsychotic agents' OR 'tranquilizing agents' combined with 'deglutition disorders' OR 'deglutition'. In Embase, we used the Emtree terms 'neuroleptic agents' combined with 'swallowing' OR 'dysphagia'. Two reviewers assessed the eligibility of each report independently. The level of evidence of the included studies was also assessed according to pre-established criteria. Case reports were excluded. We found 18 clinical studies of dysphagia related to antipsychotics: 12 were related both to typical and atypical antipsychotics, four to atypical antipsychotics and two to typical antipsychotics. According to the clinical studies included, prevalence of patients with swallowing problems taking antipsychotics ranged from 21.9 to 69.5% whereas prevalence of patients without swallowing problems taking antipsychotics ranged from 5 to 30.5%. The available evidence suggests considering an etiology of dysphagia in patients with swallowing problems who are taking antipsychotics, even if no other symptoms are present. Although few general conclusions can be drawn from current evidence, both typical and atypical antipsychotics can be associated with OD.

The in Vitro Actions of Loxapine on Dopaminergic and Serotonergic Receptors. Time to Consider Atypical Classification of This Antipsychotic Drug?

BACKGROUND

The denomination of typical antipsychotic for loxapine has poor relation to current knowledge of the molecule's relevant modes of action.

MATERIALS AND METHODS

Competition binding experiments were performed on expressed human recombinant receptors in CHO cells and HEK-293 cells for D1 to D5, 5-HT1A, 5-HT2A, 5-HT2C, 5-HT4, 5-HT6, and 5-HT7. In vitro autoradiographies using [11C]-Raclopride [18F]-Altanserin [18F]-MPPF [11C]-SB207145, and [18F]-2FNQ1P were measured in brain tissue of a male primate followed by addition of increasing doses of loxapine succinate.

RESULTS

In cell cultures, the measured Kb confirmed high affinity of loxapine for the D2; intermediate affinity for the D1, D4, D5, 5-HT2C receptorsl and a lack of affinity toward D3, 5-HT1A, 5-HT4, 5-HT6, and 5-HT7 receptors. In brain tissue, PET autoradiographies showed a radiopharmaceutical displacement at low concentrations of loxapine on D2 and 5-HT2A receptors.

CONCLUSION

This preclinical study reveals that loxapine receptorial spectrum is close to an "atypical" profile (D2/5HT2A ratio, 1.14). Loxapine is rightly classified as a DS-RAn agent in the Neuroscience Based Nomenclature classification.

Does early antipsychotic response predict long-term treatment outcome?

OBJECTIVE

Early antipsychotic response within the first 2-3 weeks of treatment can predict short-term outcomes after several months. We conducted the current study to determine whether the predictive value of early antipsychotic response persists throughout long-term treatment over multiple years.

METHODS

In this observational study, we conducted follow-up assessments of 64 patients with first-episode psychosis an average of 25 months after they began antipsychotic treatment. Patients were initially randomized to receive haloperidol or olanzapine, but treatment after the acute hospitalization period was not controlled. Regression analyses were used to determine whether early improvement on the Brief Psychiatric Rating Scale at 2 or 3 weeks predicted longer term improvement at follow-up. We conducted secondary analyses to determine whether early response could predict extrapyramidal side effects at follow-up.

RESULTS

Early response to haloperidol at 2 weeks predicted Brief Psychiatric Rating Scale improvement on longer term follow-up (p = .002). Longer term improvement was not predicted by early response to olanzapine at 2 weeks (p = .726) or 3 weeks (p = .541). Rates of extrapyramidal side effects did not differ between treatment groups and were not predicted by early response.

CONCLUSION

These results demonstrate the long-term prognostic value of early haloperidol response. The predictive value of early olanzapine response may be less robust.

In silico repurposing of antipsychotic drugs for Alzheimer's disease

Background

Alzheimer’s disease (AD) is the most prevalent form of dementia and represents one of the highest unmet requirements in medicine today. There is shortage of novel molecules entering into market because of poor pharmacokinetic properties and safety issues. Drug repurposing offers an opportunity to reinvigorate the slowing drug discovery process by finding new uses for existing drugs. The major advantage of the drug repurposing approach is that the safety issues are already investigated in the clinical trials and the drugs are commercially available in the marketplace. As this approach provides an effective solution to hasten the process of providing new alternative drugs for AD, the current study shows the molecular interaction of already known antipsychotic drugs with the different protein targets implicated in AD using in silico studies.

Result

A computational method based on ligand–protein interaction was adopted in present study to explore potential antipsychotic drugs for the treatment of AD. The screening of approximately 150 antipsychotic drugs was performed on five major protein targets (AChE, BuChE, BACE 1, MAO and NMDA) by molecular docking. In this study, for each protein target, the best drug was identified on the basis of dock score and glide energy. The top hits were then compared with the already known inhibitor of the respective proteins. Some of the drugs showed relatively better docking score and binding energies as compared to the already known inhibitors of the respective targets. Molecular descriptors like molecular weight, number of hydrogen bond donors, acceptors, predicted octanol/water partition coefficient and percentage human oral absorption were also analysed to determine the in silico ADME properties of these drugs and all were found in the acceptable range and follows Lipinski’s rule.

Conclusion

The present study have led to unravel the potential of leading antipsychotic drugs such as pimozide, bromperidol, melperone, anisoperidone, benperidol and anisopirol against multiple targets associated with AD. Benperidol was found to be the best candidate drug interacting with different target proteins involved in AD.

Psychotropic in the environment: risperidone residues affect the behavior of fish larvae

The ability to avoid and escape from predators are clearly relevant behaviors from the ecological perspective and directly interfere with the survival of organisms. Detected in the aquatic environment, risperidone can alter the behavior of exposed species. Considering the risk of exposure in the early stages of life, we exposed zebrafish embryos to risperidone during the first 5 days of life. Risperidone caused hyperactivity in exposed larvae, which in an environmental context, the animals may be more vulnerable to predation due to greater visibility or less perception of risk areas.

Extrapyramidal side effects of antipsychotics are linked to their association kinetics at dopamine D2 receptors

Atypical antipsychotic drugs (APDs) have been hypothesized to show reduced extrapyramidal side effects (EPS) due to their rapid dissociation from the dopamine D₂ receptor. However, support for this hypothesis is limited to a relatively small number of observations made across several decades and under different experimental conditions. Here we show that association rates, but not dissociation rates, correlate with EPS. We measured the kinetic binding properties of a series of typical and atypical APDs in a novel time-resolved fluorescence resonance energy transfer assay, and correlated these properties with their EPS and prolactin-elevating liabilities at therapeutic doses. EPS are robustly predicted by a rebinding model that considers the microenvironment of postsynaptic D₂ receptors and integrates association and dissociation rates to calculate the net rate of reversal of receptor blockade. Thus, optimizing binding kinetics at the D₂ receptor may result in APDs with improved therapeutic profile.

Atypical antipsychotics show reduced extrapyramidal side effects compared to first generation drugs. Here the authors use time-resolved FRET to measure binding kinetics, and show that side effects correlate with drug association rates to the D₂ receptor, while dissociation rates correlate with prolactin elevation.

Drug repurposing may generate novel approaches to treating depression

Objectives

The breakthrough advancements in scientific medical research have greatly improved our understanding of the pathogenesis of depression, encouraging drug discoverers to take a shorter path than ever through drug repurposing to generate new antidepressant medications. In addition to reduced noradrenergic and serotonergic neurotransmission in the brain, other coincidence features such as glutamate neurotoxicity, inflammation and/or cerebrovascular insufficiency are implicated in the pathogenesis of major depressive disorder and late-life depression. This short review discusses the progress made in repurposing drugs for antidepressant actions.

Key findings

Drugs being repurposed as antidepressants act on novel drug targets, thereby treating resistant depression and improving remission rate. Drugs such as ketamine, dextromethorphan/quinidine and scopolamine are rapidly acting antidepressants targeting glutamate receptors. Nimodipine and quetiapine are efficient add-on therapy for late-life depression. Anti-inflammatory drugs, statins, insulin sensitizers, minocycline could remarkably contribute to treating refractory depression.

Summary

Drug repurposing represents an alternative approach to cope with major obstacles, including financial insufficiency and unavoidable long lag evaluation time, undermining the classical pathway of developing new hit compounds into clinically approved antidepressants.

Ameliorative effect of chlorpromazine hydrochloride on visceral hypersensitivity in rats: possible involvement of 5-HT2A receptor

BACKGROUND AND PURPOSE

Visceral hypersensitivity is responsible for pathogenesis of irritable bowel syndrome (IBS). Therefore, its prevention can help avoid abdominal pain and discomfort in IBS. To find candidate drugs for visceral hypersensitivity, we screened existing medicines for their ability to prevent visceral sensitivity induced by colorectal distension (CRD) in rats and identified chlorpromazine, a typical antipsychotic drug, as a candidate compound. In this study, we investigated the effect of chlorpromazine on visceral hypersensitivity.

EXPERIMENTAL APPROACH

Visceral sensitivity (visceromotor response) was monitored by measuring the electrical activity of the abdominal external oblique muscle contraction in response to CRD using a barostat apparatus. Visceral hypersensitivity was induced by a colonic instillation of sodium butyrate or acetic acid in neonates.

KEY RESULTS

Oral administration of chlorpromazine suppressed butyrate-induced visceral hypersensitivity to CRD. Interestingly, atypical antipsychotic drugs, quetiapine and risperidone, ameliorated butyrate-induced visceral hypersensitivity, whereas the typical antipsychotic drugs, haloperidol and sulpiride, did not. Pharmacological analysis using specific inhibitors showed that a selective 5-HT_2A receptor antagonist, ketanserin, suppressed butyrate-induced visceral hypersensitivity, whereas a selective dopamine D₂ receptor antagonist, L-741626, did not. Furthermore, the 5-HT_2A receptor agonist AL-34662 stimulated visceral sensitivity to CRD in healthy control rats but not in butyrate-treated rats. These findings suggest that increased 5-HT levels in the colon contribute to the induction of visceral hypersensitivity.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that chlorpromazine ameliorates visceral hypersensitivity and that the 5-HT_2A receptor is a potential therapeutic target for treating abdominal pain and discomfort in IBS.

Drug information update. Atypical antipsychotics and neuroleptic malignant syndrome: nuances and pragmatics of the association

Neuroleptic malignant syndrome (NMS) is a rare but potentially fatal adverse event associated with the use of antipsychotics. Although atypical antipsychotics were initially considered to carry no risk of NMS, reports have accumulated over time implicating them in NMS causation. Almost all atypical antipsychotics have been reported to be associated with NMS. The clinical profile of NMS caused by certain atypical antipsychotics such as clozapine has been reported to be considerably different from the NMS produced by typical antipsychotics, with diaphoresis encountered more commonly, and rigidity and tremor encountered less frequently. This article briefly discusses the evidence relating to the occurrence, presentation and management of NMS induced by atypical antipsychotics.

Cariprazine for the Treatment of Bipolar Disorder

PURPOSE

To review the data regarding a new antipsychotic, cariprazine.

CONCLUSIONS

Cariprazine is a dopamine D3, D2 partial agonist, with greater affinity to D3. It has been examined for schizophrenia, bipolar mania, bipolar depression, and unipolar depression. It has demonstrated efficacy in schizophrenia and mania, and has recently been approved by the U.S. Food and Drug Administration. However, it has a more inconsistent effect in depression, both unipolar and bipolar. Adverse effects include extrapyramidal symptoms, akathisia, and gastrointestinal distress.

PRACTICE IMPLICATIONS

Cariprazine will be a promising addition in the treatment of patients with acute mania and schizophrenia.

Associations of NEUROD2 polymorphisms and change of cognitive dysfunctions in schizophrenia and schizoaffective disorder after eight weeks of antipsychotic treatment

INTRODUCTION

NEUROD2 is a neurospecific helix-loop-helix transcription factor which has an impact on the regulation of glutamatergic and GABAergic genes. We investigated an association of NEUROD2 with neurocognitive dysfunctions in schizophrenia and schizoaffective disorder patients before and during treatment with different second-generation antipsychotics.

METHODS

Patients were genotyped for four different polymorphisms of the NEUROD2 gene ((rs9889354(A/G), rs1877032(C/T), rs12453682(C/T) and rs11078918(C/G)). Cognitive function was assessed at baseline and week 8. Results of individual neuropsychological tests were assigned to six cognitive domains (reaction time and quality; executive function; working, verbal and visual memory) and a general cognitive index.

RESULTS

167 patients were included in the study. The NEUROD2 exonic polymorphism rs11078918 showed significant associations with verbal memory and executive functions, whereas the NEUROD2 polymorphism rs12453682 was significantly associated with working and verbal memory, executive functions and with a cognitive index. Significant associations were found at baseline and after eight weeks. Moreover, significant associations between the change in neuropsychological test results during antipsychotic treatment and the NEUROD2 polymorphisms rs11078918 and rs12453682 were observed.

CONCLUSIONS

Our findings suggest that the NEUROD2 gene could play a role in the pathophysiology of neurocognitive dysfunctions as well as in the change of cognitive symptoms under antipsychotic treatment in schizophrenia and schizoaffective disorder.

Effect of clozapine on ketamine-induced deficits in attentional set shift task in mice

RATIONALE

Clozapine (CLZ) is an effective treatment for schizophrenia, producing improvements in both negative symptoms and cognitive impairments. Cognitive impairments can be modelled in animals by ketamine (KET) and assessed using the attentional set-shift task (ASST).

OBJECTIVE

Our first aim was to determine whether CLZ improves cognitive function and reverses KET-induced cognitive impairments using the ASST. Our second aim was to assess dose dependency of these effects.

RESULTS

Our findings demonstrate that acute as well as sub-chronic administration of KET cause cognitive deficits observed as increase in number of trails and errors to reach the criterion in the EDS phase. CLZ 0.3 mg/kg reversed the effects of both acute and sub-chronic KET, with no effects on locomotor activity. However, clozapine's effect after sub-chronic administration of dose 0.3 mg/kg was not as explicit as in the case of acute treatment. Moreover, administration of 1 mg/kg CLZ to KET-treated mice induced or enhanced deficits in the extra-dimensional shift phase compared to 1 mg/kg CLZ administration to mice not receiving KET. Locomotor activity test showed sedation effects of CLZ 1 mg/kg after acute treatment; therefore, effect of CLZ 1 mg/kg on KET-induced cognitive deficits was not evaluated in the attentional set-shift task (ASST) test.

CONCLUSIONS

The present findings support dose-dependent effects of CLZ to reverse KET-induced cognitive deficits. The observed dose dependency may be mediated by activation of different receptors, including monomers and/or heterodimers.

Psychosis in Parkinson's Disease: Epidemiology, Pathophysiology, and Management

Psychotic symptoms are common in Parkinson's disease (PD) and are associated with poorer quality of life and increased caregiver burden. PD psychosis is correlated with several factors, such as more advanced disease, cognitive impairment, depression, and sleep disorders. The underlying causes of psychosis in PD thus involve a complex interplay between exogenous (e.g., drugs, intercurrent illnesses) and endogenous (e.g., PD disease pathology) factors. Current theories of the pathophysiology of PD psychosis have come from several neuropathological and neuroimaging studies that implicate pathways involving visual processing and executive function, including temporo-limbic structures and neocortical gray matter with altered neurotransmitter functioning (e.g., dopamine, serotonin, and acetylcholine). Treatment of PD psychosis requires a step-wise process, including initial careful investigation of treatable triggering conditions and a comprehensive evaluation with adjustment of PD medications and/or initiation of specific antipsychotic therapies. Clozapine remains the only recommended drug for the treatment of PD psychosis; however, because of regular blood monitoring, quetiapine is usually first-line therapy, although less efficacious. Emerging studies have focused on agents involving other neurotransmitters, including the serotonin 5-HT2A receptor inverse agonist pimavanserin, cholinesterase inhibitors, and antidepressants and anxiolytics.

Predictors of smoking reduction outcomes in a sample of 287 patients with schizophrenia spectrum disorders

Many studies have investigated whether a type of antipsychotics or type of adjuvant is associated with smoking reduction in patients with schizophrenia. However, there has been no study exploring a comprehensive range of factors related to smoking reduction in schizophrenia patients. We analyzed a dataset of 287 smoking patients with schizophrenia who participated in an 8-week open-label study with high- (n = 90) or low-dose nicotine dermal patches (n = 132) or bupropion (n = 65). A logistic regression model and a linear mixed model were used to explore factors associated with the outcomes of smoking cessation and reduction, i.e., the number of cigarettes smoked and the level of nicotine dependence. The total cessation rate was 6.3 % (18/287). There were no significant predictors of cessation. The time effect of reduction was significant during the program (p = 0.001). Type of antipsychotics (p = 0.018), readiness to quit (p = 0.014), baseline number of cigarettes smoked per day (p = 0.001), and nicotine dependence level (p = 0.001) were significantly associated with smoking reduction. Patients on first-generation antipsychotics (n = 129) or clozapine (n = 70) reduced their smoking more than those on non-clozapine second-generation antipsychotics (n = 74). Patients in the preparation stage (n = 97) or in the contemplation (n = 70) reduced their smoking more than those in the precontemplation stage (n = 120). The mechanisms of tobacco addiction need to be better understood for further development of effective cessation programs in patients with schizophrenia.

Development of spiroguanidine-derived α7 neuronal nicotinic receptor partial agonists

We describe the synthesis of quinuclidine-containing spiroguanidines and their utility as α7 neuronal nicotinic acetylcholine receptor (nAChR) partial agonists. The convergent synthetic route developed for this study allowed for rapid SAR investigation and provided access to a structurally diverse set of analogs. A potent and selective α7 nAChR partial agonist, N-(6-methyl-1,3-benzoxazol-2-yl)-3',5'-dihydro-4-azaspiro[bicyclo[2.2.2]octane-2,4'-imidazole]-2'-amine (BMS-910731, 16), was identified. This compound induced immediate early genes c-fos and Arc in a preclinical rodent model of α7 nAChR-derived cellular activation and plasticity. Importantly, the ability to incorporate selectivity for the α7 nACh receptor over the 5-HT_3A receptor in this series suggested a significant difference in steric requirements between the two receptors.

Mitragyna speciosa Leaf Extract Exhibits Antipsychotic-Like Effect with the Potential to Alleviate Positive and Negative Symptoms of Psychosis in Mice

In this study, we investigated the antipsychotic-like effect of methanolic extract of Mitragyna speciosa leaf (MMS) using in vivo and ex vivo studies. In vivo studies comprised of apomorphine-induced climbing behavior, haloperidol-induced catalepsy, and ketamine-induced social withdrawal tests in mice whereas the ex vivo study was conducted utilizing isolated rat vas deferens preparation. Acute oral administration of MMS (50–500 mg/kg) showed an inverted bell-shaped dose-response in apomorphine-induced cage climbing behavior in mice. The effective inhibitory doses of MMS (75 and 100 mg/kg, p.o.) obtained from the apomorphine study was further tested on haloperidol (subcataleptic dose; 0.1 mg/kg, i.p.)-induced catalepsy in the mouse bar test. MMS (75 and 100 mg/kg, p.o.) significantly potentiated the haloperidol-induced catalepsy in mice. Interestingly, MMS at the same effective doses (75 and 100 mg/kg, p.o.) significantly facilitated the social interaction in ketamine-induced social withdrawal mice. Furthermore, MMS inhibited the dopamine-induced contractile response dose-dependently in the isolated rat vas deferens preparations. In conclusion, this investigation provides first evidence that MMS exhibits antipsychotic-like activity with potential to alleviate positive as well as negative symptoms of psychosis in mice. This study also suggests the antidopaminergic activity of MMS that could be responsible for alleviating positive symptoms of psychosis.

Arterial Stiffness in Patients Taking Second-generation Antipsychotics

Objective

That treatment with second-generation antipsychotics (SGAs) causes metabolic side effects and atherosclerosis in patients with schizophrenia and bipolar disorder (BD) is well-known. Increased arterial stiffness is an important marker of arteriosclerosis and has been identified as an independent risk factor for cardiovascular diseases. We measured pulse wave velocity (PWV) as a marker of arteriosclerosis in patients with schizophrenia and BD who use SGAs.

Methods

Patients and controls were collected from our psychiatry outpatient clinics or family medicine. Mental illness was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition. Mean age, gender, systolic and diastolic blood pressure, body mass index, Framingham risk score (FRS), etc. were determined. Simultaneous electrocardiography and pulse wave were recorded with an electromyography device. The photo-plethysmographic method was used to record the pulse wave. Inclusion criteria included use of SGAs for at least the last six months. Patients with diseases that are known to cause stiffness and the use of typical antipsychotics were excluded.

Results

Ninety-six subject (56 patients, 40 controls) were included in our study. There were 49 females, 47 males. Patients had schizophrenia (n=17) and BD (n=39). Their treatments were quetiapine (n=15), risperidone (n=13), olanzapine (n=15), and aripiprazole (n=13). Although differences in mean age, gender, and FRS in the patient and control groups were not statistically significant (p=1), PWV was greater in patients in the antipsychotic group (p=0.048).

Conclusion

This study supported the liability to stiffness in patients with schizophrenia and BD. Using SGAs may contribute to arterial stiffness in these patients.