The different trajectories of antipsychotic response: antipsychotics versus placebo

The efficacy and heterogeneity of antipsychotic response in schizophrenia: A meta-analysis

The response to antipsychotic treatment in schizophrenia appears to vary, and as such it has been proposed that different subtypes of schizophrenia exist, defined by treatment-response. This has not been formally examined using meta-analysis. Randomised controlled trials comparing placebo and antipsychotics in acute treatment of schizophrenia listed in PubMed, EMBASE and PsycINFO from inception until 30 November 2018 were examined. Relative variability of symptomatic improvement in antipsychotic-treated individuals compared to placebo-treated individuals was quantified using coefficient of variation ratio (CVR). Mean difference in symptom change was quantified using Hedges' g. In addition, individual patient data from two clinical trials was examined in terms of both the distribution of total symptom change, and the variability of individual symptoms and symptom factors. In total, 11,006 articles were identified. Sixty six met inclusion criteria, reporting on 17,202 patients. Compared with placebo, antipsychotic-treated patients demonstrated greater total symptom improvement (g = 0.47, p < 0.001) and reduced variability in symptomatic improvement for total (CVR = 0.86, p < 0.001), positive (CVR = 0.89, p < 0.001), and negative symptoms (CVR = 0.86, p = 0.001). Lower variability in antipsychotic-response relative to placebo was associated with studies published earlier (z = 3.98, p < 0.001), younger patients (z = 3.07, p = 0.002), higher dose treatments (z = -2.62, p = 0.009), and greater mean-difference in symptom-change (z = -5.70, p < 0.001). In the individual patient dataset (N = 522 patients), antipsychotic treated patients did not show significantly increased variability for any individual symptom, and there was no evidence of a bimodal distribution of response. Compared to placebo, antipsychotic treatment shows greater improvement and lower variability of change in total, positive and negative symptoms. This is contrary to the hypothesis that there is a subtype of antipsychotic non-responsive schizophrenia. Instead our findings, provide evidence for a relatively homogeneous effect of antipsychotic treatment in improving symptoms of schizophrenia.

Longitudinal trajectory analysis of antipsychotic response in patients with schizophrenia: 6-week, randomised, open-label, multicentre clinical trial

BACKGROUND

Understanding the patterns of treatment response is critical for the treatment of patients with schizophrenia; one way to achieve this is through using a longitudinal dynamic process study design.

AIMS

This study aims to explore the response trajectory of antipsychotics and compare the treatment responses of seven different antipsychotics over 6 weeks in patients with schizoprenia (trial registration: Chinese Clinical Trials Registry Identifier: ChiCTR-TRC-10000934).

METHOD

Data were collected from a multicentre, randomised open-label clinical trial. Patients were evaluated with the Positive and Negative Syndrome Scale (PANSS) at baseline and follow-up at weeks 2, 4 and 6. Trajectory groups were classified by the method of k-means cluster modelling for longitudinal data. Trajectory analyses were also employed for the seven antipsychotic groups.

RESULTS

The early treatment response trajectories were classified into a high-trajectory group of better responders and a low-trajectory group of worse responders. The results of trajectory analysis showed differences compared with the classification method characterised by a 50% reduction in PANSS scores at week 6. A total of 349 patients were inconsistently grouped by the two methods, with a significant difference in the composition ratio of treatment response groups using these two methods (χ2 = 43.37, P < 0.001). There was no differential contribution of high- and low trajectories to different drugs (χ2 = 12.52, P = 0.051); olanzapine and risperidone, which had a larger proportion in the >50% reduction at week 6, performed better than aripiprazole, quetiapine, ziprasidone and perphenazine.

CONCLUSIONS

The trajectory analysis of treatment response to schizophrenia revealed two distinct trajectories. Comparing the treatment responses to different antipsychotics through longitudinal analysis may offer a new perspective for evaluating antipsychotics.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: Updated recommendations from the British Association for Psychopharmacology

These updated guidelines from the British Association for Psychopharmacology replace the original version published in 2011. They address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting was held in 2017, involving experts in schizophrenia and its treatment. They were asked to review key areas and consider the strength of the evidence on the risk-benefit balance of pharmacological interventions and the clinical implications, with an emphasis on meta-analyses, systematic reviews and randomised controlled trials where available, plus updates on current clinical practice. The guidelines cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. It is hoped that the practice recommendations presented will support clinical decision making for practitioners, serve as a source of information for patients and carers, and inform quality improvement.

Should people with psychosis be supported in choosing cognitive therapy as an alternative to antipsychotic medication: A commentary on current evidence

Evidence from randomised controlled trials suggest that both antipsychotic medication and cognitive behaviour therapy (CBT) can be helpful to people with a diagnosis of a schizophrenia spectrum disorder. On this basis, many clinical guidelines recommend that people with psychosis should be offered both antipsychotic medication and CBT and that they should be collaboratively involved in the decisions about which treatment options they choose. The reality of service provision is often very different, with data regarding the availability of such treatment options and the extent of user involvement in decision making suggesting that medication is much more widely available and that service users are often not involved in these decisions, despite retaining decision making capacity. Many patients choose not to take antipsychotic medication, often due to inefficacy or side effects, but there is little evidence regarding whether CBT can be effective as an alternative to antipsychotic medication. However, several recent trials suggest that CBT without medication may be a safe and acceptable option for people with psychosis. The implications for clinical practice and future research are considered and it is recommended that informed choices that include the option to try CBT without antipsychotic medication are supported.

Rate of and time to symptomatic remission in first-episode psychosis in Northern Malawi: A STROBE-compliant article

Although longer duration of untreated psychosis (DUP) is associated with poor response to antipsychotic treatment, it remains unclear whether it independently influences time to symptomatic remission in first-episode psychosis (FEP). This study examined rate of symptomatic remission, and explored if DUP, premorbid functioning, global functioning, insight and socio-demographic characteristics were independently associated with time to symptomatic remission in FEP.This prospective study enrolled 126 FEP patients (aged 18-65) between June 2009 and September 2012. Subjects were followed-up monthly over 18 months after they had received antipsychotic medication. Remission in positive and negative symptoms was defined as in the Remission in Schizophrenia Working Group (RSWG) criteria. Subjects were defined as "in symptomatic remission" if they remitted in both negative and positive symptoms. At baseline, the following explanatory variables were measured: socio-demographic characteristics; DUP as short (≤5 months) and long (>5 months); premorbid functioning as deteriorating, stable poor, and stable good according to Cannon-Spoor Premorbid Adjustment Scale; global functioning as "worst (1-10) to serious (41-50)" and "moderate (51-60) to superior (91-100)," according to the Global Assessment of Functioning Scale; and insight as poor (≤8) and good (≥9) according to the Insight Scale (Birchwood). Univariate and multivariable analyses were used to generate results.Out of 126 subjects, 98 (78%) completed follow-up, of which 70 (71.4%) achieved symptomatic remission within mean duration of 8.05 (4.54) months. Besides, having long DUP and separated/divorced/widowed (adjusted hazard ratio [aHR] = 0.07, 95%CI = [0.01, 0.46]), long DUP and poor insight (aHR = 0.18, 95%CI = [0.04, 0.89]), poor insight and separated/divorced/widowed (aHR = 0.09, 95%CI = [0.01, 0.70]), deteriorating premorbid functioning (aHR = 0.47, 95%CI = [0.23, 0.97]), family history of psychiatric disorders (aHR = 0.52, 95%CI = (0.30, 0.93]), and being male (aHR = 0.47, 95%CI = [0.24, 0.92]) delayed symptomatic remission.These results propose that psychological interventions and social support for mental health problems are warranted and may enhance better response to antipsychotic medications among separated/divorced/widowed patients with long DUP or poor insight, and poor insight patients with long DUP. Deteriorating premorbid functioning, family history of psychiatric disorders and being male continue being important risk factors for poor odds of remission.

Trajectories of depressive symptoms in the acute phase of psychosis: Implications for treatment

Depression is common in schizophrenia and associated with negative outcomes. Previous studies have identified heterogeneity in treatment response in schizophrenia. We aimed to investigate different trajectories of depression in patients suffering from psychosis and predictors of change in depressive symptoms during antipsychotic treatment. Two hundred and twenty-six patients >18 years acutely admitted due to psychosis were consecutively included and the follow-up was 27 weeks. The Calgary Depression Scale for Schizophrenia (CDSS) sum score was the primary outcome. Latent growth curve (LGCM) and Growth Mixture Models (GMM) were conducted. Predictors were the Positive sum score of the Positive and Negative Syndrome Scale for Schizophrenia (PANSS), Schizophrenia spectrum/non-spectrum psychoses, gender and being antipsychotic naive at inclusion. We found support for three depression-trajectories, including a high- (14.7%), a low depression-level (69.6%) class and a third depressed class quickly decreasing to a low level (15.7%). Change in CDSS was associated with change in PANSS positive score in all time intervals (4 weeks: b = 0.18, p < 0.001, 3 months: 0.21, p < 0.023, 6 months: 0.43, p < 0.001) and with a diagnosis within schizophrenia spectrum but not with antipsychotic naivety or gender. The schizophrenia-spectrum patients had less depressive symptoms at inclusion (-2.63, p < 0.001). In conclusion, an early responding and a treatment refractory group were identified. The treatment-refractory patients are candidates for enhanced anti-depressive treatment, for which current evidence is limited. The post-psychotic depression group was characterized by depressive symptoms in the acute phase as well. We could not identify differentiating characteristics of the depression trajectories.

Mechanisms of the placebo effect in pain and psychiatric disorders

Placebo effect research over the past 15 years has improved our understanding of how placebo treatments reduce patient symptoms. The expectation of symptom improvement is the primary factor underlying the placebo effect. Such expectations are shaped by past experiences, contextual cues and biological traits, which ultimately modulate one's degree of response to a placebo. The body of evidence that describes the physiology of the placebo effect has been derived from mechanistic studies primarily restricted to the setting of pain. Imaging findings support the role of endogenous opioid and dopaminergic networks in placebo analgesia in both healthy patients as well as patients with painful medical conditions. In patients with psychiatric illnesses such as anxiety disorders or depression, a vast overlap in neurological changes is observed in drug responders and placebo responders supporting the role of serotonergic networks in placebo response. Molecular techniques have been relatively underutilized in understanding the placebo effect until recently. We present an overview of the placebo responder phenotypes and genetic markers that have been associated with the placebo effect in pain, schizophrenia, anxiety disorders and depression.

Challenging the understanding of significant improvement and outcome in schizophrenia - the concept of reliable and clinically significant change methods

Significant changes of schizophrenia patients during inpatient treatment were evalutaed and compared to established outcome criteria. The concept of reliable and clinically significant change methods was applied to three hundred and ninety-six patients suffering from a schizophrenia spectrum disorder. First, information on whether or not the change of the patient's condition is sufficient in order to declare that it is beyond a measurement error or random effect (= reliable change) was evaluated and in a second step it was observed if the reliable change was clinically meaningful (= clinically significant change). Different Positive and Negative Syndrome Scale for Schizophrenia (PANSS) thresholds were applied to define the clinically significant change (40, 45 and 50 points). These changes were then compared to established outcome criteria such as response and remission. Seventy-nine of the 396 patients (20%) showed a reliable improvement of symptoms, whereas 70% improved without achieving a reliable change of their condition. Of the 79 patients achieving a reliable change during treatment 8-15% concurrently showed a clinically significant change depending on the respective PANSS threshold. In contrast, 56% of the patients achieved response and 60% were in remission at discharge when applying established outcome criteria. Our results showed that a rather small number of schizophrenia patients were found to reliably change during inpatient treatment, with even less patients achieving a clinically significant change. The concept of reliable and clinically significant changes revealed to be a lot more stringent than today's established outcome criteria and should be critically evaluated regarding its use in schizophrenia patients.

Psychological therapies for auditory hallucinations (voices): current status and key directions for future research

This report from the International Consortium on Hallucinations Research considers the current status and future directions in research on psychological therapies targeting auditory hallucinations (hearing voices). Therapy approaches have evolved from behavioral and coping-focused interventions, through formulation-driven interventions using methods from cognitive therapy, to a number of contemporary developments. Recent developments include the application of acceptance- and mindfulness-based approaches, and consolidation of methods for working with connections between voices and views of self, others, relationships and personal history. In this article, we discuss the development of therapies for voices and review the empirical findings. This review shows that psychological therapies are broadly effective for people with positive symptoms, but that more research is required to understand the specific application of therapies to voices. Six key research directions are identified: (1) moving beyond the focus on overall efficacy to understand specific therapeutic processes targeting voices, (2) better targeting psychological processes associated with voices such as trauma, cognitive mechanisms, and personal recovery, (3) more focused measurement of the intended outcomes of therapy, (4) understanding individual differences among voice hearers, (5) extending beyond a focus on voices and schizophrenia into other populations and sensory modalities, and (6) shaping interventions for service implementation.

Antipsychotic dosing: found in translation

In the field of schizophrenia research, as in other areas of psychiatry, there is a sense of frustration that greater advances have not been made over the years, calling into question existing research strategies. Arguably, many purported gains claimed by research have been "lost in translation," resulting in limited impact on diagnosis and treatment in the clinical setting. There are exceptions; for example, we would argue that different lines of preclinical and clinical research have substantially altered how we look at antipsychotic dosing. While this story remains a work in progress, advances "found in translation" have played an important role. Detailing these changes, the present paper speaks to a body of evidence that has already shifted clinical practice and raises questions that may further alter the manner in which antipsychotics have been administered over the last 6 decades.

Treatment response heterogeneity in the predominant negative symptoms of schizophrenia: analysis of amisulpride vs placebo in three clinical trials

BACKGROUND

The extent of heterogeneity in response to the psychopharmacological treatment of negative symptoms is unknown.

AIMS

To examine the extent of heterogeneity in response to the treatment of predominantly negative symptoms of schizophrenia.

METHOD

Data were analyzed from three clinical trials that compared placebo or amisulpride for up to 60days. Trial participants had predominantly negative symptoms of schizophrenia (n=485). Heterogeneity of percentage reduction on the Scale for the Assessment of Negative Symptoms (SANS) was examined with trajectory-group based modeling followed by descriptive statistics and the prediction of trajectory group membership with logistic regression modeling. Analyses were repeated separately for the placebo and amisulpride groups.

RESULTS

Trajectory group-based modeling identified groups of non- (n=297, 61.2%), gradual-moderate (n=135, 27.8%) and rapid- (n=53, 10.9%) responders. At baseline compared to non-responders, rapid-responders had consistently significantly (p<.05) higher SANS total and subscale scores. Percent SANS improvement at endpoint was greatest for the rapid-responders group, a finding that replicated stratifying by placebo and amisulpride treatment groups. Similarly, in the total sample and stratifying by placebo and amisulpride groups, dropout was not significantly associated with trajectory group membership.

CONCLUSIONS

Trajectories of treatment response to the psychopharmacological medication of the negative symptoms of schizophrenia demonstrate substantial heterogeneity. Approximately half of the patients included in our analysis showed little improvement, and the most severely ill at baseline responded the most.

Cluster analysis of cognitive deficits may mark heterogeneity in schizophrenia in terms of outcome and response to treatment

Cognitive impairments are central to schizophrenia, but their clinical utility for tagging heterogeneity in lifetime outcome and response to treatment is not conclusive. By exploiting four cognitive domains consistently showing large deficits in studies, we tested whether cluster analysis would define separate subsets of patients and then whether the disease heterogeneity marked by these clusters would be related to lifetime outcome and response to treatment. A total of 112 schizophrenia patients completed a neuropsychological evaluation. The PANSS, GAF-S and GAF-F were rated at the onset and endpoint of the illness trajectory. A blind judgment of the lifetime response to treatment was made. The first cluster presented near-normal cognitive performance. Two other clusters of severely impaired patients were identified: one generally impaired in the four cognitive domains and another selectively impaired in visual episodic memory and processing speed, each relating to a different lifetime evolution of disease and treatment response. Although the two impaired clusters were clinically indistinguishable in symptom severity and functioning at disease onset, patients with selective cognitive impairments demonstrated better improvement at outcome, whereas the generally impaired patients were more likely to be treatment refractory. The findings have implications for the management of patients and for clinical trials since particular combinations of cognitive deficits in patients would influence their treatment response.

The neurobiology of relapse in schizophrenia

Dopamine's proposed role in psychosis proved a starting point in our understanding of the neurobiology of relapse, fitting given the central role positive symptoms play. This link is reflected in early work examining neurotransmitter metabolite and drug (e.g. amphetamine, methylphenidate) challenge studies as a means of better understanding relapse and predictors. Since, lines of investigation have expanded (e.g. electrophysiological, immunological, hormonal, stress), an important step forward if relapse per se is the question. Arguably, perturbations in dopamine represent the final common pathway in psychosis but it is evident that, like schizophrenia, relapse is heterogeneous and multidimensional. In understanding the neurobiology of relapse, greater gains are likely to be made if these distinctions are acknowledged; for example, efforts to identify trait markers might better be served by distinguishing primary (i.e. idiopathic) and secondary (e.g. substance abuse, medication nonadherence) forms of relapse. Similarly, it has been suggested that relapse is 'neurotoxic', yet individuals do very well on clozapine after multiple relapses and the designation of treatment resistance. An alternative explanation holds that schizophrenia is characterized by different trajectories, at least to some extent biologically and/or structurally distinguishable from the outset, with differential patterns of response and relapse. Just as with schizophrenia, it seems naïve to conceptualize the neurobiology of relapse as a singular process. We propose that it is shaped by the form of illness and in place from the outset, modified by constitutional factors like resilience, as well as treatment, and confounded by secondary forms of relapse.

Trajectories of symptom dimensions in short-term response to antipsychotic treatment in patients with a first episode of non-affective psychosis

BACKGROUND

Trajectory patterns of positive, disorganized and negative dimension symptoms during antipsychotic treatment in drug-naive patients with first-episode psychosis have yet to be examined by using naturalistic data.

METHOD

This pragmatic clinical trial randomized 161 drug-naive patients with a first episode of psychosis to olanzapine, risperidone or haloperidol. Patients were assessed with the Scale for the Assessment of Negative Symptoms (SANS) and Positive Symptoms (SAPS) at baseline and at the end of weeks 1, 2, 3, 4 and 6 of antipsychotic treatment. Censored normal models of response trajectories were developed with three dimensions of the SAPS-SANS scores (positive, disorganized and negative) in order to identify the different response trajectories. Diagnosis, cannabis use, duration of untreated psychosis (DUP), smoking and antipsychotic class were examined as possible predictive variables.

RESULTS

Patients were classified in five groups according to the positive dimension, three groups according to the disorganized dimension and five groups according to the negative dimension. Longer DUPs and cannabis use were associated with higher scores and poorer responses in the positive dimension. Cannabis use was associated with higher scores and poorer responses in the disorganized dimension. Only schizophrenia diagnosis was associated with higher scores and poorer responses in the negative dimension.

CONCLUSIONS

Our results illustrate the heterogeneity of short-term response to antipsychotics in patients with a first episode of psychosis and highlight markedly different patterns of response in the positive, disorganized and negative dimensions. DUP, cannabis use and diagnosis appeared to have a prognostic value in predicting treatment response with different implications for each dimension.

The longitudinal interplay between negative and positive symptom trajectories in patients under antipsychotic treatment: a post hoc analysis of data from a randomized, 1-year pragmatic trial

BACKGROUND

Schizophrenia is a highly heterogeneous disorder with positive and negative symptoms being characteristic manifestations of the disease. While these two symptom domains are usually construed as distinct and orthogonal, little is known about the longitudinal pattern of negative symptoms and their linkage with the positive symptoms. This study assessed the temporal interplay between these two symptom domains and evaluated whether the improvements in these symptoms were inversely correlated or independent with each other.

METHODS

This post hoc analysis used data from a multicenter, randomized, open-label, 1-year pragmatic trial of patients with schizophrenia spectrum disorder who were treated with first- and second-generation antipsychotics in the usual clinical settings. Data from all treatment groups were pooled resulting in 399 patients with complete data on both the negative and positive subscale scores from the Positive and Negative Syndrome Scale (PANSS). Individual-based growth mixture modeling combined with interplay matrix was used to identify the latent trajectory patterns in terms of both the negative and positive symptoms. Pearson correlation coefficients were calculated to examine the relationship between the changes of these two symptom domains within each combined trajectory pattern.

RESULTS

We identified four distinct negative symptom trajectories and three positive symptom trajectories. The trajectory matrix formed 11 combined trajectory patterns, which evidenced that negative and positive symptom trajectories moved generally in parallel. Correlation coefficients for changes in negative and positive symptom subscale scores were positive and statistically significant (P < 0.05). Overall, the combined trajectories indicated three major distinct patterns: (1) dramatic and sustained early improvement in both negative and positive symptoms (n = 70, 18%), (2) mild and sustained improvement in negative and positive symptoms (n = 237, 59%), and (3) no improvement in either negative or positive symptoms (n = 82, 21%).

CONCLUSIONS

This study of symptom trajectories over 1 year shows that changes in negative and positive symptoms were neither inversely nor independently related with each other. The positive association between these two symptom domains supports the notion that different symptom domains in schizophrenia may depend on each other through a unified upstream pathological disease process.

Drug and alcohol trajectories among adults with schizophrenia: data from the CATIE study

OBJECTIVE

The primary aim is to describe drug and alcohol trajectories in adults with schizophrenia.

METHOD

Growth mixture models were used to examine disordered and non-disordered use and abstinence in the Clinical Antipsychotic Trials of Intervention Effectiveness study.

RESULTS

Five classes - always abstinent; fluctuating use, abuse, and occasional abstinence; occasional (ab)use; stopped (ab)use; abusing - fit best. Overlap exists between always abstinent drug and alcohol classes; less overlap exists across other classes.

CONCLUSION

There is heterogeneity in drug and alcohol use among adults with schizophrenia. The lack of overlap between classes, save always abstinent, suggests modeling drug and alcohol use separately.

Non-random dropout and the relative efficacy of escitalopram and nortriptyline in treating major depressive disorder

Most comparisons of the efficacy of antidepressants have relied on the assumption that missing data are randomly distributed. Dropout rates differ between drugs, suggesting this assumption may not hold true. This paper examines the effect of non-random dropout on a comparison of two antidepressant drugs, escitalopram and nortriptyline, in the treatment of major depressive disorder. The GENDEP study followed adult patients with major depressive disorder over 12 weeks of treatment, and the primary analysis found no difference in efficacy of the two antidepressants under missing at random assumption. By applying the recently developed Muthén-Roy model, we compared the relative efficacy of these two antidepressants taking into account non-random distribution of missing outcomes (NMAR). Individuals who dropped out of the study were those who were not responding to treatment. Based on the best fitting NMAR model, it was found that escitalopram reduced symptom scores by an additional 1.4 points on the Montgomery-Åsberg Depression Rating Scale (p = 0.02), equivalent to 5% of baseline depression severity, compared to nortriptyline. We conclude that association between dropout and worsening symptoms led to an overestimate of the effectiveness of treatment, especially with nortriptyline, in the primary analysis. These findings review the primary analysis of GENDEP and suggest that, when non-random dropout is accounted for, escitalopram is more effective than nortriptyline in reducing symptoms of major depression.

Antipsychotics: is it time to introduce patient choice?

Evidence regarding overestimation of the efficacy of antipsychotics and underestimation of their toxicity, as well as emerging data regarding alternative treatment options, suggests it may be time to introduce patient choice and reconsider whether everyone who meets the criteria for a schizophrenia spectrum diagnosis requires antipsychotics in order to recover.

Response trajectories in "real-world" naturalistically treated schizophrenia patients

BACKGROUND

To date, research has identified distinct antipsychotic response trajectories yet focussing on data from randomized-controlled trials (RCTs). Therefore, the heterogeneity of response in "real-world" schizophrenia patients is still unknown.

METHODS

Antipsychotic response was evaluated in 399 patients suffering from a schizophrenia spectrum disorder within a naturalistic multicenter study of the Competence Network on Schizophrenia using latent class regression. Baseline and illness-related variables were compared between the different trajectory classes as well as currently proposed outcome definitions (early improvement, response, remission) using univariate tests. In order to predict the trajectory group membership classification and regression tree analysis were furthermore performed.

RESULTS

Five distinct trajectories of antipsychotic response were identified: Class 1 (15%) showing an early and considerable improvement, Class 2 (14%) incorporating patients with the greatest response to treatment, Class 3 (34%) again showing an early improvement to treatment yet with a slightly lower degree of improvement, Class 4 (22%) featuring patients gradually responding to treatment, and Class 5 (15%) with the poorest antipsychotic response. Fewer depressive symptoms at admission, better functioning, a shorter duration of illness and less previous hospitalizations were found to be significant predictors of good response. No considerable differences were found comparing the present results to the previous trajectory analyses deriving from RCTs.

CONCLUSION

Our results underline the heterogeneous course of response independent of the study or treatment design suggesting that the diversity in schizophrenia response and outcome is determined primarily by different pathophysiological underpinnings.

Effects of drop-out on efficacy estimates in five Cochrane reviews of popular antipsychotics for schizophrenia

OBJECTIVE

Our aim was to find out how Cochrane reviews of five popular or frequently prescribed second-generation antipsychotics in the UK (olanzapine, risperidone, quetiapine, amisulpride and aripiprazole) approached the problem of high drop-out in placebo-controlled trials.

METHOD

We examined the following: (i) whether reviews included data from studies with a level of drop-out exceeding their stated exclusion criterion; (ii) the level of missing data each efficacy outcome in each review relied upon; and (iii) impact of excluding studies with high drop-out.

RESULTS

All reviews included data they stated they would exclude because of unacceptable levels of attrition, four (risperidone, olanzapine, amisulpride, aripiprazole) without clear acknowledgement or justification. Several reviews also excluded data from a number of relatively low-attrition studies because of missing standard deviations.

CONCLUSION

Cochrane reviews of five popular antipsychotics for schizophrenia misrepresented the available evidence on their efficacy. The impact of including high-attrition studies was difficult to quantify because of the exclusion of relevant low-attrition studies. Further analysis of the efficacy of these drugs in studies with acceptable rates of attrition is required. To reduce the problem of high attrition, trialists should gather follow-up data from people who leave the double-blind process early.

Randomized controlled trials in schizophrenia: opportunities, limitations, and trial design alternatives

State-of-the art clinical trial design and methodology are enormously important for the advancement of the field. In contrast, the critical relevance of trial conduct and implementation have only more recently been the focus of discussion and research. Although randomized controlled trials are generally considered the gold standard for the assessment of pharmacologic and nonpharmacologic interventions in medicine, trials are vulnerable to complications and influences that can seriously compromise their success, Like interventions, trial design and conduct are also contextual. They need to be individualized and adapted to a number of relevant variables, such as setting, population, illness phase, interventions, patient and rater expectations and biases, and the overall aims of the investigation. While this means that there is no unified approach possible, certain general principles and guidelines require careful consideration. Knowledge of basic solutions and alternatives, and the recognition of the complex challenges that need to be addressed proactively can help to minimize unwanted outcomes, including trial failure and uninformative or falsely negative outcomes. Moreover, novel design alternatives need to be explored that target sample enrichment according to the study question and enhancement of precision in the measurement of relevant outcomes. We propose two novel design strategies that take advantage of the recently validated early antipsychotic response paradigm (that has also been observed with antidepressants and mood stabilizers). In the “early responder randomized discontinuation design” all patients are assigned to the active drug, and only those who had at least a minimal response at 2 weeks are enrolled in a double-blind, placebo-controlled discontinuation trial, enriching the placebo controlled trial portion with true drug responders. In the mirror image “early nonresponder randomized dose increase or augmentation design,” early nonresponders at 2 weeks are assigned to staying on the medication or going either to a higher dose or an augmentation agent. It is hoped that through increased attention to the issues raised in this article and further refinement of trial methodology and conduct, the field will make much needed additional progress in the prevention and treatment of schizophrenia.

The heterogeneity of antipsychotic response in the treatment of schizophrenia

BACKGROUND

Schizophrenia is a heterogeneous disorder in terms of patient response to antipsychotic treatment. Understanding the heterogeneity of treatment response may help to guide treatment decisions. This study was undertaken to capture inherent patterns of response to antipsychotic treatment in patients with schizophrenia, characterize the subgroups of patients with similar courses of response, and examine illness characteristics at baseline as possible predictors of response.

METHOD

Growth mixture modeling (GMM) was applied to data from a randomized, double-blind, 12-week study of 628 patients with schizophrenia or schizo-affective disorder treated with risperidone or olanzapine.

RESULTS

Four distinct response trajectories based on Positive and Negative Syndrome Scale (PANSS) total score over 12 weeks were identified: Class 1 (420 patients, 80.6%) with moderate average baseline PANSS total score showing gradual symptom improvement; Class 2 (65 patients, 12.5%) showing rapid symptom improvement; Class 3 (24 patients, 4.6%) with high average baseline PANSS total score showing gradual symptom improvement; and Class 4 (12 patients, 2.3%) showing unsustained symptom improvement. Latent class membership of early responders (ER) and early non-responders (ENR) was determined based on 20% symptom improvement criteria at 2 weeks and ultimate responders (UR) and ultimate non-responders (UNR) based on 40% symptom improvement criteria at 12 weeks. Baseline factors with potential influence on latent class membership were identified.

CONCLUSIONS

This study identified four distinct treatment response patterns with predominant representation of responders or non-responders to treatment in these classes. This heterogeneity may represent discrete endophenotypes of response to treatment with different etiologic underpinnings.