The SOHO (Schizophrenia Outpatient Health Outcome) study: implications for the treatment of schizophrenia

Antagonism of dopamine D2 receptor/beta-arrestin 2 interaction is a common property of clinically effective antipsychotics

Since the unexpected discovery of the antipsychotic activity of chlorpromazine, a variety of therapeutic agents have been developed for the treatment of schizophrenia. Despite differences in their activities at various neurotransmitter systems, all clinically effective antipsychotics share the ability to interact with D2 class dopamine receptors (D2R). D2R mediate their physiological effects via both G protein-dependent and independent (beta-arrestin 2-dependent) signaling, but the role of these D2R-mediated signaling events in the actions of antipsychotics remains unclear. We demonstrate here that while different classes of antipsychotics have complex pharmacological profiles at G protein-dependent D2R long isoform (D2(L)R) signaling, they share the common property of antagonizing dopamine-mediated interaction of D2(L)R with beta-arrestin 2. Using two cellular assays based on a bioluminescence resonance energy transfer (BRET) approach, we demonstrate that a series of antipsychotics including haloperidol, clozapine, aripiprazole, chlorpromazine, quetiapine, olanzapine, risperidone, and ziprasidone all potently antagonize the beta-arrestin 2 recruitment to D2(L)R induced by quinpirole. However, these antipsychotics have various effects on D2(L)R mediated G(i/o) protein activation ranging from inverse to partial agonists and antagonists with highly variable efficacies and potencies at quinpirole-induced cAMP inhibition. These results suggest that the different classes of clinically effective antipsychotics share a common molecular mechanism involving inhibition of D2(L)R/beta-arrestin 2 mediated signaling. Thus, selective targeting of D2(L)R/beta-arrestin 2 interaction and related signaling pathways may provide new opportunities for antipsychotic development.

Limitations of current therapies: why do patients switch therapies?

The results of recent studies, including the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study, the Cost Utility of the Latest Antipsychotic Drugs in Schizophrenia Study (CUtLASS), the European Schizophrenia Outpatient Health Outcome (SOHO), and the Spanish EFESO study have given some insight into why, in the course of real-world treatment, patients with schizophrenia discontinue or ask to be switched to other medications. Disappointingly, these studies consistently demonstrate that there is not one answer for these patients. The data from these studies indicate that an individual approach to treatment is required, and by doing this the need to adjust medications in advance of problems may be addressed. A combination of knowledge of the potential impact of each antipsychotic, typical or newer, alongside a more informed view of quality of life needs for these patients, might be useful to maximise treatment compliance of the currently available treatment options - with the potential for a not inconsiderable impact on efficacy in schizophrenia.

Adverse effects of antipsychotics as outcome measures

BACKGROUND

Antipsychotic drugs are associated with adverse effects that can lead to poor medication adherence, stigma, distress and impaired quality of life.

AIMS

To review the use of adverse effects of antipsychotic drugs as outcome measures, with a particular emphasis on methodological issues.

METHOD

Review of data on adverse effects from sources including randomised controlled trials (RCTs), post-marketing surveillance and naturalistic studies.

RESULTS

All have advantages and disadvantages and the best overview comes from considering all sources of data together. Adverse effects are inconsistently reported, hampering cross-study comparisons. Many outcome measures lack clinical meaning. In both naturalistic studies and RCTs adverse effects often account for less treatment discontinuation than lack of efficacy.

CONCLUSIONS

Standardisation in the reporting of adverse effects is needed. Patients' subjective experience of medication should be given more consideration. Total discontinuation rates provide a useful global outcome measure that incorporates tolerability and efficacy as well as patient and clinician viewpoints. Patients should be informed of common side-effects prior to treatment and monitored for their occurrence during treatment.

Medication adherence in schizophrenia: patient perspectives and the clinical utility of paliperidone ER

Antipsychotic medications provide the foundation for treatment of acute exacerbations as well as relapse prevention in patients with schizophrenia as demonstrated by rigorous placebo-controlled trials. However, despite their proven effectiveness, poor adherence to prescribed antipsychotic regimens remains the most important driver of suboptimal clinical outcomes in this population. This paper reviews the magnitude of the problem of medication non-adherence in patients with schizophrenia and the various factors that contribute to non-adherence, with particular emphasis on factors related to antipsychotic medications. The profile of the latest atypical antipsychotic, paliperidone extended-release (ER) tablets, is then reviewed and the implications of its unique pharmacokinetic profile for adherence in this patient population are discussed.

A randomized, flexible-dose, quasi-naturalistic comparison of quetiapine, risperidone, and olanzapine in the short-term treatment of schizophrenia: the QUERISOLA trial

This was a randomized, flexible-dose, rater-blind, parallel-group, quasi-naturalistic trial comparing the efficacy, safety, and tolerability of quetiapine, risperidone, and olanzapine in patients with schizophrenia hospitalized for severe psychotic symptoms. Seventy-five patients were randomized to quetiapine (n=25), risperidone (n=25), or olanzapine (n=25). Mean doses at Week 8 were: 590.0 mg/day quetiapine; 5.1 mg/day risperidone; 15.1 mg/day olanzapine. Four quetiapine, five risperidone, and five olanzapine patients discontinued prior to Week 8. There were no significant differences between groups in the primary efficacy measures of improvement from baseline in Positive and Negative Syndrome Scale (PANSS) total score at Week 8 in the per protocol (PP) population and the number of completers who experienced >or=40% improvement on the same scale. PP and intent-to-treat analyses showed significant improvement from baseline in each component of a PANSS-derived battery, without significant differences between treatments. No quetiapine patients, one risperidone, and four olanzapine patients reported an adverse event (AE) of moderate intensity; no severe AEs were reported. A linear mixed model for repeated measures showed an effect of treatment on body weight, with significant differences favoring quetiapine over risperidone and olanzapine. Simpson-Angus Scale scores were significantly worse with risperidone compared with both olanzapine and quetiapine at Week 3 and compared with quetiapine thereafter. Use of concomitant medications for anxiety or tension was significantly less frequent with quetiapine. In conclusion, quetiapine, risperidone, and olanzapine have similar efficacy in schizophrenia, but there are drug-specific differences for some AEs and in the use of concomitant medication that differentiate these agents.

Atypical antipsychotic-induced metabolic side effects: insights from receptor-binding profiles

Atypical antipsychotic drugs offer several notable benefits over typical antipsychotics, including greater improvement in negative symptoms, cognitive function, prevention of deterioration, and quality of life, and fewer extrapyramidal symptoms (EPS). However, concerns about EPS have been replaced by concerns about other side effects, such as weight gain, glucose dysregulation and dyslipidemia. These side effects are associated with potential long-term cardiovascular health risks, decreased medication adherence, and may eventually lead to clinical deterioration. Despite a greater understanding of the biochemical effects of these drugs in recent years, the pharmacological mechanisms underlying their various therapeutic properties and related side effects remain unclear. Besides dopamine D(2) receptor antagonism, a characteristic feature of all atypical antipsychotic drugs, these agents also bind to a range of non-dopaminergic targets, including serotonin, glutamate, histamine, alpha-adrenergic and muscarinic receptors. This review examines the potential contribution of different receptors to metabolic side effects associated with atypical antipsychotic treatment for all seven agents currently marketed in the United States (risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole, paliperidone and clozapine) and another agent (bifeprunox) in clinical development at the time of this publication.

Pharmacogenetics of antipsychotic adverse effects: Case studies and a literature review for clinicians

There is a growing body of literature supporting the contribution of genetic variability to the mechanisms responsible for the adverse effects of antipsychotic medications particularly movement disorders and weight gain. Despite the current gap between research studies and the practical tools available to the clinician to identify such risks, it is hoped that in the foreseeable future, pharmacogenetics will become a critical aid to guide the development of personalized therapeutic regimes with fewer adverse effects. We provide a summary of two cases that are examples of using cytochrome P450 pharmacogenetics in an attempt to guide treatment in the context of recent literature concerning the role of pharmacogenetics in the manifestation of adverse effects of antipsychotic therapies. These examples and the review of recent literature on pharmacogenetics of antipsychotic adverse effects illustrate the potential for applying the principles of predictive, preventive, and personalized medicine to the therapy of psychotic disorders.

Clinical trials: bridging the gap between efficacy and effectiveness

The need for clinical psychiatry research to provide practical information to clinicians, families, and consumers has led to the development of new approaches to clinical trials. Efficacy trials, the historical backbone of clinical research, have many shortcomings in delivering practical information to stakeholders. The 'effectiveness' or 'public-health' model of intervention research targets a diverse group of patients across multiple settings that are outside of academic medical centres, with study design and outcomes that are selected on the basis of their potential to produce clinically meaningful information. The National Institute of Mental Health has funded three such clinical trials in recent years, respectively targeting schizophrenia and Alzheimer's disease, depression, and bipolar disorder. Each of these studies has made a major impact, and provided new insights into the challenges of public health orientated trials in psychiatry. In this review, we describe the underlying principles and practical considerations in efficacy and effectiveness-orientated trials.

Practical prescribing with aripiprazole in schizophrenia: consensus recommendations of a UK multidisciplinary panel

BACKGROUND

The atypical antipsychotic, aripiprazole, differs from other antipsychotics in its pharmacology and clinical outcomes. Aripiprazole's clinical outcomes include beneficial effects on mood, quality of life and cognition; favourable tolerability with low potential for sedation; and a favourable physical health profile, with low potential for weight change, sexual dysfunction or adverse metabolic effects. Such outcomes, particularly cognitive improvements, may allow for greater psychosocial intervention and improved social inclusion. In accordance with the UK NICE guidance on the use of antipsychotic treatment for schizophrenia (2002), aripiprazole may be an appropriate therapeutic option for patients with schizophrenia who are newly diagnosed, in acute relapse or experiencing tolerability problems, adverse metabolic effects or dissatisfaction with their current medication.

SCOPE

A multidisciplinary panel was convened in the UK in October 2006 to discuss and provide practical guidance regarding the potential benefits and risks of prescribing aripiprazole. This report describes the consensus recommendations agreed during the meeting and includes practical guidance on the optimal approach to prescribing aripiprazole, which patients might benefit from aripiprazole and how best to approach initiation of and switching to treatment with aripiprazole. A PubMed/MEDLINE literature search was conducted to support these recommendations.

FINDINGS

To support antipsychotic therapy, a therapeutic partnership should be established between the patient and a well-informed, multidisciplinary care team. Aripiprazole should be initiated at the minimal efficacious dose (10 mg/day) and titrated as required (usually to 15 mg/day) after a minimum of 2 weeks. The primary goal during aripiprazole initiation is to ensure the patient completes the first few days of treatment, with support from concomitant medications if required. Nausea, insomnia and agitation may occur in 10-20% of patients, but are manageable and typically resolve during the first 3-7 days of therapy. The dose of any prior antipsychotic should remain stable until the response to aripiprazole is satisfactory and then the previous antipsychotic should be tapered off slowly over several weeks or more.

CONCLUSION

Patients are more likely to adhere to treatment with aripiprazole--and indeed any other antipsychotic--and derive long-term therapeutic benefits if they and a well-informed care team are involved in the treatment decision, establish a therapeutic partnership, are aware of the transient nature of any adverse events and understand what the potential long-term benefits are.

Amisulpride-induced tardive dyskinesia

Tardive dyskinesia (TD) is a movement disorder that develops during the course of long-term treatment with neuroleptic agents and is characterized primarily by choreiform and athetotic movements. We report the case of a 34-year-old man suffering from schizophrenia, disorganized type. He received amisulpride (400 mg daily) and the result was much improvement. 20 months later, he was presented with TD, which resolved almost completely after change of treatment to 1200 mg quetiapine without any relapsing. To our knowledge, his is the first case report in the literature of tardive dyskinesia induced by amisulpride.