Correlation between delay in initiating clozapine and symptomatic improvement

Neurocognition and NMDAR co-agonists pathways in individuals with treatment resistant first-episode psychosis: a 3-year follow-up longitudinal study

This study aims to determine whether 1) individuals with treatment-resistant schizophrenia display early cognitive impairment compared to treatment-responders and healthy controls and 2) N-methyl-D-aspartate-receptor hypofunction is an underlying mechanism of cognitive deficits in treatment-resistance. In this case‒control 3-year-follow-up longitudinal study, n = 697 patients with first-episode psychosis, aged 18 to 35, were screened for Treatment Response and Resistance in Psychosis criteria through an algorithm that assigns patients to responder, limited-response or treatment-resistant category (respectively resistant to 0, 1 or 2 antipsychotics). Assessments at baseline: MATRICS Consensus Cognitive Battery; N-methyl-D-aspartate-receptor co-agonists biomarkers in brain by MRS (prefrontal glutamate levels) and plasma (D-serine and glutamate pathways key markers). Patients were compared to age- and sex-matched healthy controls (n = 114). Results: patient mean age 23, 27% female. Treatment-resistant (n = 51) showed lower scores than responders (n = 183) in processing speed, attention/vigilance, working memory, verbal learning and visual learning. Limited responders (n = 59) displayed an intermediary phenotype. Treatment-resistant and limited responders were merged in one group for the subsequent D-serine and glutamate pathway analyses. This group showed D-serine pathway dysregulation, with lower levels of the enzymes serine racemase and serine-hydroxymethyltransferase 1, and higher levels of the glutamate-cysteine transporter 3 than in responders. Better cognition was associated with higher D-serine and lower glutamate-cysteine transporter 3 levels only in responders; this association was disrupted in the treatment resistant group. Treatment resistant patients and limited responders displayed early cognitive and persistent functioning impairment. The dysregulation of NMDAR co-agonist pathways provides underlying molecular mechanisms for cognitive deficits in treatment-resistant first-episode psychosis. If replicated, our findings would open ways to mechanistic biomarkers guiding response-based patient stratification and targeting cognitive improvement in clinical trials.

Long-term outcomes of delayed clozapine initiation in treatment-resistant schizophrenia: a multicenter retrospective cohort study

BACKGROUND

Clozapine is the only antipsychotic medication with proven efficacy against treatment-resistant schizophrenia. This multicenter retrospective cohort study aimed to evaluate the impact of a delay in clozapine initiation on long-term outcomes.

METHODS

Patients who initiated clozapine treatment between July 2009 and December 2018 were included in this study. According to the length of time from the diagnosis of schizophrenia to clozapine initiation, the patients were categorized into one of three groups: early (≤ 9 years), intermediate (10-19 years), and late (≥ 20 years) initiation. The endpoints were psychiatric rehospitalization and all-cause clozapine discontinuation within 3 years. Hazard ratios (HR) and 95% confidence interval (CI) were estimated using the Fine and Gray method or the Cox proportional hazards model.

RESULTS

The incidence rates of rehospitalization within three years, according to the cumulative incidence function, were 32.3% for early, 29.7% for intermediate, and 62.2% for late initiation, respectively. Late initiation had a significantly higher risk of psychiatric rehospitalization than early initiation (HR, 2.94; 95% CI, 1.01- 8.55; P = 0.016 by the Gray's test). The risk of psychiatric rehospitalization was not significantly different between the early and intermediate initiation groups. The incidence rate of all-cause clozapine discontinuation within three years using the Kaplan-Meier method was 13.0% for early, 10.6% for intermediate, and 20.1% for late initiation. The risk of all-cause clozapine discontinuation was not significantly among the groups. The late initiation group had more patients discontinuing because of death due to physical diseases than the other groups.

CONCLUSIONS

The study suggests that clozapine should be initiated promptly in patients with treatment-resistant schizophrenia to prevent psychiatric rehospitalization during long-term treatment. Further prospective studies with appropriate consideration of confounding factors and large sample sizes are needed to strengthen the evidence.

Dopamine supersensitivity psychosis and delay of clozapine treatment in patients with treatment-resistant schizophrenia

Both the underutilization of clozapine and treatment resistance of patients to clozapine are serious problems worldwide. Identifying clinical markers predicting response to clozapine would help clinicians more effectively utilize clozapine treatment. The present study retrospectively assessed dopamine supersensitivity psychosis (DSP) in addition to other measures such as age at disease onset and delay of clozapine introduction for a total of 47 treatment-resistant schizophrenia (TRS) patients. The response to clozapine was judged with CGI-C at 1 and 2 years from clozapine introduction. Results revealed that the DSP group tended to have a longer delay between designation of TRS and introduction of clozapine and continued to have slightly more severe psychopathology after treatment with clozapine, showing only slight improvement. The logistic regression analysis showed that the age at disease onset was the only significant indicator, predicting responsiveness to clozapine: patients with an onset age <20 years had a significantly better response to clozapine than patients with an onset age ≥20 years. The present study suggests that DSP might be related to a longer delay in clozapine introduction and the persistence of refractory symptoms despite clozapine treatment, whereas early age of disease onset might be related to a better response to clozapine.

Antipsychotic prescribing practices for outpatients with schizophrenia and reasons for non-clozapine treatment - Data from a Danish quality assessment audit

BACKGROUND

Clozapine is the gold standard for treating treatment-resistant schizophrenia (TRS) although widely underutilised. Both organisational, patient- and clinician related reasons for the underutilisation have been reported, however, the clinical impact of either in real-world settings is not fully elucidated.

AIM

This audit aimed to evaluate the local antipsychotic (AP) prescribing practices for outpatients with schizophrenia and to assess the spectrum and prevalence of journalised reasons for non-clozapine treatment amongst eligible outpatients.

METHODS

Data on demographics, current and former AP treatments, as well as documented reasons for non-clozapine treatment, was extracted through chart audit.

RESULTS

Of the 668 affiliated outpatients with schizophrenia, 43% were treated with AP polytherapy (APP) and 19.6% with clozapine. The most prevalent reason for clozapine discontinuation was related to side effects whereas the most prevalent reason for refusal or omission of clozapine treatment was related to the associated monitoring regimen.

CONCLUSIONS

This audit showed that APP prescribing is a highly prevalent practice in our services when treating outpatients with schizophrenia and that clozapine is underutilised in a 'last resort' manner. The blood-monitoring regimen associated with clozapine treatment was found to be an important factor in the underutilisation. It seemed, however, that the monitoring constituted a barrier for different reasons, requiring different approaches to remedy. Future studies, directly involving both patients and clinicians in the identification and management of the most clinically relevant barriers and their corresponding facilitators, are warranted.

Antipsychotics-Induced Changes in Synaptic Architecture and Functional Connectivity: Translational Implications for Treatment Response and Resistance

Schizophrenia is a severe mental illness characterized by alterations in processes that regulate both synaptic plasticity and functional connectivity between brain regions. Antipsychotics are the cornerstone of schizophrenia pharmacological treatment and, beyond occupying dopamine D2 receptors, can affect multiple molecular targets, pre- and postsynaptic sites, as well as intracellular effectors. Multiple lines of evidence point to the involvement of antipsychotics in sculpting synaptic architecture and remodeling the neuronal functional unit. Furthermore, there is an increasing awareness that antipsychotics with different receptor profiles could yield different interregional patterns of co-activation. In the present systematic review, we explored the fundamental changes that occur under antipsychotics' administration, the molecular underpinning, and the consequences in both acute and chronic paradigms. In addition, we investigated the relationship between synaptic plasticity and functional connectivity and systematized evidence on different topographical patterns of activation induced by typical and atypical antipsychotics.

A Guideline and Checklist for Initiating and Managing Clozapine Treatment in Patients with Treatment-Resistant Schizophrenia

Treatment-resistant schizophrenia (TRS) will affect about one in three patients with schizophrenia. Clozapine is the only treatment approved for TRS, and patients should be treated as soon as possible to improve their chances of achieving remission. Despite its effectiveness, concern over side effects, monitoring requirements, and inexperience with prescribing often result in long delays that can expose patients to unnecessary risks and compromise their chances of achieving favorable long-term outcomes. We critically reviewed the literature on clozapine use in TRS, focusing on guidelines, systematic reviews, and algorithms to identify strategies for improving clozapine safety and tolerability. Based on this, we have provided an overview of strategies to support early initiation of clozapine in patients with TRS based on the latest evidence and our clinical experience, and have summarized the key elements in a practical, evidence-based checklist for identifying and managing patients with TRS, with the aim of increasing confidence in prescribing and monitoring clozapine therapy.

Dopaminergic dysfunction and excitatory/inhibitory imbalance in treatment-resistant schizophrenia and novel neuromodulatory treatment

Antipsychotic drugs are the mainstay in the treatment of schizophrenia. However, one-third of patients do not show adequate improvement in positive symptoms with non-clozapine antipsychotics. Additionally, approximately half of them show poor response to clozapine, electroconvulsive therapy, or other augmentation strategies. However, the development of novel treatment for these conditions is difficult due to the complex and heterogenous pathophysiology of treatment-resistant schizophrenia (TRS). Therefore, this review provides key findings, potential treatments, and a roadmap for future research in this area. First, we review the neurobiological pathophysiology of TRS, particularly the dopaminergic, glutamatergic, and GABAergic pathways. Next, the limitations of existing and promising treatments are presented. Specifically, this article focuses on the therapeutic potential of neuromodulation, including electroconvulsive therapy, repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and deep brain stimulation. Finally, we propose multivariate analyses that integrate various perspectives of the pathogenesis, such as dopaminergic dysfunction and excitatory/inhibitory imbalance, thereby elucidating the heterogeneity of TRS that could not be obtained by conventional statistics. These analyses can in turn lead to a precision medicine approach with closed-loop neuromodulation targeting the detected pathophysiology of TRS.

Association between the examination rate of treatment-resistant schizophrenia and the clozapine prescription rate in a nationwide dissemination and implementation study

BACKGROUND

The decision to initiate clozapine treatment should be made on an individual basis and may be closely related to the early detection of treatment-resistant schizophrenia (TRS), although there is evidence that the early use of clozapine results in a better response to treatment. Therefore, we investigated the relationship between the examination rate of TRS and the prescription rate of clozapine.

METHODS

After attending a 1-day educational program on schizophrenia based on the "Guidelines for the Pharmacological Treatment of Schizophrenia," we asked the participating facilities to submit records of whether or not TRS was evaluated for each patient. We calculated the clozapine prescription rate from the schizophrenic patients prescribed clozapine and all of the schizophrenic patients. Forty-nine facilities in 2017 were included in the study.

RESULTS

There were dichotomous distributions in the examination rate of TRS and a non-normal distribution in the prescription rate of clozapine. There was a significant correlation between the prescription rate of clozapine and the examination rate of TRS (r s  = 0.531, P = 1.032 × 10-4 ). A significant difference was found in the prescription rate of clozapine between the three groups of facilities according to the examination rate of TRS.

CONCLUSION

As a preliminary problem for the use of clozapine, in Japan, the examination rate of TRS varies, and there are many facilities that typically do not consider the possibility of TRS; this trend leads to a low rate of clozapine use. Clearly, further clinician training is needed for the early detection and appropriate management of TRS that includes an explanation of TRS and how to introduce clozapine therapy to patients and their families.

Impact cérébral structurel et fonctionnel de la Clozapine chez les patients souffrant de schizophrénie : revue systématique des études longitudinales en neuroimagerie

OBJECTIF

L'objectif de cette revue est d'identifier les corrélats anatomo-fonctionnels cérébraux lors d'un traitement par clozapine (CLZ) ainsi que les marqueurs anatomo-fonctionnels prédictifs de la réponse à la CLZ.

MÉTHODES

Nous avons réalisé une revue systématique de la littérature avec les bases de données MEDLINE et Web of Science afin d'identifier et d'examiner toutes les études longitudinales en neuroimagerie investiguant l'impact cérébral de la CLZ.

RÉSULTATS

30 études ont été incluses et analysées. La CLZ induit une diminution du volume et de la perfusion dans les noyaux gris centraux chez les patients répondeurs. Un plus grand volume de substance grise et perfusion dans ces structures avant l'instauration de la CLZ étaient associés à une meilleure réponse au traitement. La diminution de volume et de perfusion au niveau du cortex préfrontal (CPF) est observée malgré l'instauration de CLZ mais de façon moins importante chez les patients sous CLZ que chez les patients sous antipsychotiques typiques. Un plus grand volume au niveau du CPF avant l'instauration de la CLZ est associé à une meilleure réponse clinique dans la majorité des études. Enfin, la CLZ semble induire une réduction des altérations au niveau de la substance blanche.

CONCLUSION

Les corrélats anatomo-fonctionnels de la CLZ différent de ceux des autres antipsychotiques avec une action spécifique de la CLZ au niveau des ganglions de la base et du CPF pouvant participer à sa supériorité en termes de réponse clinique. Plusieurs données cliniques et d'imagerie conduisent à l'hypothèse d'un meilleur pronostic associé à une instauration plus rapide de la CLZ.

Treatment Resistance: A Time-Based Approach for Early Identification in First Episode Psychosis

Although approximately 1/3 of individuals with schizophrenia are Treatment Resistant (TR), identifying these subjects prospectively remains challenging. The Treatment Response and Resistance in Psychosis working group defines <20% improvement as an indicator of TR, though its utility in First Episode Schizophrenia (FES) remains unknown. In a prospective cohort of FES (n = 129) followed up for 5 years, we evaluated two improvement thresholds for ‘probable TR’; <20% and <50% based on positive, negative, and total symptoms. We ascertained (1) the ecological validity (i.e., the ability to identify an expected subgroup of 1/3rd of patients); (2) the predictive validity (i.e., ability to predict poor global functioning) and (3) the clinical utility (association with clozapine use at the 5th year). Using the criteria of a total symptom reduction of <50% or negative symptom reduction of <20% resulted in ‘probable TR’ rates of 37% and 33%, respectively. Using <20% positive or total symptoms criteria resulted in very low rates, indicating minimal utility in FES. <50% total symptom criterion best predicted the global functioning over 5 years. Clozapine use was only predicted by positive symptom criterion. Prospective characterization of TRS is possible at 6 months after FES through a time-based approach using a 50% threshold for symptom change in treatment-adherent patients.

Deficits in attentional modulation of auditory N100 in first-episode schizophrenia

Reductions of the auditory N100 are present in schizophrenia, even at the first episode (FESz). Because most studies examine auditory N100 on active target detection oddball tasks, it remains unclear if the abnormality in FESz results from sensory deficits or impaired enhancement of N100 by selective attention, or both. N100 was recorded from 21 FESz and 22 matched healthy controls (HC) on a single-tone task and a two-tone oddball task. Overall, N100 was smaller in FESz (p = .036). Attention enhanced N100 amplitude (p < .001), but this differed between groups, with FESz impaired in N100 modulation (group x attention, p = .012). The oddball task showed greater N100 enhancement than the single-tone task (p < .001) in both groups. Group differences in N100 enhancement in the oddball task were large (Cohen's d = 0.85). Exploratory correlations showed that better N100 enhancement on the oddball task in FESz was associated with better MATRICS Overall Composite scores (cognitive tasks highly sensitive to psychosis), lower PANNS Negative factor and SANS scores, and better interpersonal (social) and role functioning in the last year. N100 during ignore conditions showed no significant difference between groups, albeit smaller in FESz, with small to medium effect sizes. Although sensory deficits in N100 are likely present, they are compounded by a failure to enhance N100 with attention. The failure of N100 enhancement by attentional gain control in FESz suggests functional dysconnection between cognitive control areas and the sensory cortex. N100 amplitude on active attention tasks may be a useful outcome biomarker for targeted enhancement of the cognitive control system.

Rationale and neurobiological effects of treatment with antipsychotics in patients with chronic schizophrenia considering dopamine supersensitivity

The long-term treatment of patients with schizophrenia often involves the management of relapses for most patients and the development of treatment resistance in some patients. To stabilize the clinical course and allow as many patients as possible to recover, clinicians need to recognize dopamine supersensitivity, which can be provoked by administration of high dosages of antipsychotics, and deal with it properly. However, no treatment guidelines have addressed this issue. The present review summarized the characteristics of long-acting injectable antipsychotics, dopamine partial agonists, and clozapine in relation to dopamine supersensitivity from the viewpoints of receptor profiles and pharmacokinetics. The potential merits and limitations of these medicines are discussed, as well as the risks of treating patients with established dopamine supersensitivity with these classes of drugs. Finally, the review discussed the biological influence of antipsychotic treatment on the human brain based on findings regarding the relationship between the hippocampus and antipsychotics.

Cognitive performance in early, treatment-resistant psychosis patients: Could cognitive control play a role in persistent symptoms?

Approximately one third of psychosis patients fail to respond to conventional antipsychotic medication, which exerts its effect via striatal dopamine receptor antagonism. The present study aimed to investigate impaired cognitive control as a potential contributor to persistent positive symptoms in treatment resistant (TR) patients. 52 medicated First Episode Psychosis (FEP) patients (17 TR and 35 non-TR (NTR)) took part in a longitudinal study in which they performed a series of cognitive tasks and a clinical assessment at two timepoints, 12 months apart. Cognitive performance at baseline was compared to that of 39 healthy controls (HC). Across both timepoints, TR patients were significantly more impaired than NTR patients in a task of cognitive control, while performance on tasks of phonological and semantic fluency, working memory and general intelligence did not differ between patient groups. No significant associations were found between cognitive performance and psychotic symptomatology, and no significant performance changes were observed from the first to second timepoint in any of the cognitive tasks within patient groups. The results suggest that compared with NTR patients, TR patients have an exacerbated deficit specific to cognitive control, which is established early in psychotic illness and stabilises in the years following a first episode.

The Neurobiology of Treatment-Resistant Schizophrenia: Paths to Antipsychotic Resistance and A Roadmap for Future Research

(Reprinted with permission from NPJ Schizophrenia (2020) 6:1).

Delaying clozapine: how long is too long?

Background

Although clozapine is the most effective drug for treatment-resistant schizophrenia, its use remains restricted in clinical practice in India. The delay in initiating treatment with clozapine and its impact on disease outcome needs evaluation.

Aim

To identify the implications of delaying clozapine initiation in clinical outcomes among people with treatment-resistant schizophrenia.

Methods

Subjects with treatment-resistant schizophrenia, stabilised on clozapine monotherapy, were recruited from the outpatient clinic of a general hospital psychiatry unit offering tertiary care services in Thrissur district, Kerala, India. A retrospective cohort design was employed, and information on duration of illness, total duration of treatment and duration of treatment with clozapine was collected. Present symptom status was measured using the Positive and Negative Syndrome Scale. Factors associated with higher symptom scores were analysed using an independent sample t test, Spearman correlation and multiple linear regression.

Results

Forty subjects stabilised on long-term clozapine therapy formed the study sample. The mean dose of clozapine used in the study population was 200 mg. The mean duration of antipsychotic treatment before starting clozapine was 89.3 months (7.4 years). The duration of treatment before starting clozapine was found to have a significant positive association with the total Positive and Negative Syndrome Scale score (correlation coefficient 0.40; p=0.01) and negative symptom score (correlation coefficient 0.33; p=0.04). The multiple regression analysis adjusting for covariates showed that the duration of treatment before starting clozapine was an independent factor associated with a higher negative symptom score in the Positive and Negative Syndrome Scale (slope β=0.05; p=0.02; R²=0.27).

Conclusion

Poor treatment outcomes in treatment-resistant schizophrenia could be secondary to a delay in initiating clozapine therapy.

Clozapine response trajectories and predictors of non-response in treatment-resistant schizophrenia: a chart review study

Although clozapine is the main antipsychotic medication for treatment-resistant schizophrenia, 40-70% of patients on clozapine have persistent psychotic symptoms (i.e. ultra-treatment-resistant schizophrenia, UTRS). We aimed to examine clozapine response/non-response patterns in patients with treatment-resistant schizophrenia, as well as determine patient clinico-demographic factors associated with long-term clozapine non-response. Clinico-demographic characteristics of 241 patients on clozapine were collected through a retrospective chart review. The median (interquartile range, IQR) follow-up from illness onset was 25.0 (IQR = 24.0) years. Clozapine response was assessed at median 10.8 (IQR = 14.0) months (Time 1, T1) and 7.2 (IQR = 13.5) years (Time 2, T2) after its initiation. It was evaluated by chart reviewers based on the information provided in clinical notes. Binomial logistic regression was used to determine clinico-demographic factors associated with clozapine non-response at both T1 and T2 (i.e. stable UTRS, S-UTRS) compared to clozapine response at both times (i.e. stable clozapine responders, S-ClozResp). Among clozapine responders (n = 122) at T1, 83.6% remained clozapine responsive and 16.4% became non-responsive at T2. In the UTRS group (n = 119) at T1, 87.4% remained clozapine non-responsive and 12.6% became responsive at T2. Duration of delay in clozapine initiation (OR = 0.94, Wald χ² = 5.33, p = 0.021) and number of pre-clozapine hospitalizations (OR = 0.95, Wald χ² = 5.20, p = 0.023) were associated with S-UTRS. Most UTRS patients were non-responsive to clozapine from the start of treatment. Preventing delay in initiating clozapine and relapses could help promote long-term clozapine response in patients with treatment-resistant schizophrenia. Future longitudinal studies are required to explore the neuropathological correlates of relapses and delay in clozapine initiation.

The neurobiology of treatment-resistant schizophrenia: paths to antipsychotic resistance and a roadmap for future research

Treatment-resistant schizophrenia (TRS), the persistence of positive symptoms despite ≥2 trials of adequate dose and duration of antipsychotic medication with documented adherence, is a serious clinical problem with heterogeneous presentations. TRS can vary in its onset (at the first episode of psychosis or upon relapse), in its severity, and in the response to subsequent therapeutic interventions (i.e., clozapine, electroconvulsive therapy). The heterogeneity of TRS indicates that the underlying neurobiology of TRS may differ not only from treatment-responsive schizophrenia but also among patients with TRS. Several hypotheses have been proposed for the neurobiological mechanisms underlying TRS, including dopamine supersensitivity, hyperdopaminergic and normodopaminergic subtypes, glutamate dysregulation, inflammation and oxidative stress, and serotonin dysregulation. Research supporting these hypotheses is limited in part by variations in the criteria used to define TRS, as well as by the biological and clinical heterogeneity of TRS. Clinical trial designs for new treatments should be informed by this heterogeneity, and further clinical research is needed to more clearly understand the underlying neurobiology of TRS and to optimize treatment for patients with TRS.

Algorithm-based pharmacotherapy for first-episode schizophrenia involuntarily hospitalized: A retrospective analysis of real-world practice

BACKGROUND

Little is known about the clinical outcomes of severely ill patients with first-episode schizophrenia spectrum disorders (FES) who are considered to lack the capacity to consent to clinical trials. We investigated the feasibility of an algorithm-based pharmacotherapy (ABP) and clinical outcomes of patients with FES involuntarily hospitalized and treated with ABP.

METHODS

We conducted a retrospective chart review of 160 patients admitted involuntarily between October 2012 and October 2015. Our algorithm aimed to delay olanzapine, standardize medications and suggest initiation of clozapine after failure (non-response or intolerability) of third-line antipsychotic treatment. The duration of each adequate antipsychotic treatment at optimal dosage was 4 weeks or more.

RESULTS

The physician adherence rate to ABP was 95%. Response and remission rates were 76.0% and 48.6% in the first adequate antipsychotic trial (Phase I, n = 146), 62.5% and 25.0% in the second adequate antipsychotic trial (Phase II, n = 32), and 16.7% and 0% in the third adequate antipsychotic trial (Phase III, n = 6). Response and remission rates in the clozapine trial (n = 9) increased to nearly the level of Phase I (66.7% and 44.4%). The treatment-resistance rate was 8.4% to 10.3%.

CONCLUSIONS

These findings suggested the validity of ABP and initiation of clozapine for treatment-resistant psychotic symptoms for even severely ill involuntarily hospitalized patients with FES.

Delays and barriers to the commencement of clozapine in eligible people with a psychotic disorder: A literature review

AIM

While the majority of individuals with a first episode of psychosis (FEP) achieve symptomatic remission with the appropriate treatment, there is a small but significant proportion who do not achieve remission of symptoms despite adequate treatment with at least two antipsychotic medications (termed treatment resistance). Clozapine is indicated in individuals who fulfil the criteria for treatment-resistant schizophrenia, however, despite it being the most effective antipsychotic medication, there can be delays in the commencement of clozapine in eligible patients.

METHODS

A systematic search was performed to identify articles reporting either the time taken to commence clozapine (or delays) in eligible individuals or articles reporting barriers to the commencement of clozapine. The initial search generated 5588 articles and of these, 18 were eligible.

RESULTS

13 studies described delays in commencing clozapine and five studies reported on the barriers to the commencement of clozapine. The duration of delay from when an individual was deemed eligible for clozapine treatment to the time of clozapine commencement ranged from 19.3 weeks to 5.5 years. In addition, the duration of illness prior to clozapine initiation ranged from 1.1 to 9.7 years. It was found that some clinicians were more inclined to prescribe antipsychotic polypharmacy or doses higher than recommended than to prescribe clozapine.

CONCLUSIONS

Delays in commencing clozapine have been consistently demonstrated. Early intervention for psychosis services are the ideal settings to identify individuals with persistent positive psychotic symptoms and commence clozapine if indicated.

Plasma dopa decarboxylase activity in treatment-resistant recent-onset psychosis patients

Treatment resistance (TR) in psychosis is a major clinical problem. A biomarker predicting TR against conventional antipsychotic drugs would be relevant, potentially reducing unnecessary delay to adequate treatment with clozapine. Dopa decarboxylase (DDC) activity in the striatum, measured with positron emission tomography, is elevated in responders, but not in treatment-resistant patients. Plasma DDC activity could be a surrogate marker for DDC brain activity, and thus a potential biomarker that could be used in daily clinical practice. Therefore, we determined plasma DDC activity in 40 male patients with recent-onset psychosis, of whom the majority had started treatment, whereby 21 turned out to be treatment responders and 19 treatment resistant during follow up. We observed no significant group differences. Furthermore, symptom severity was not associated with plasma DCC activity. We did observe a trend level difference in the distribution of plasma DDC activity across categories of medication, with subsequent post hoc analysis showing lower DDC activity in risperidone-using patients. This may suggest that risperidone could influence plasma DDC activity. Based on these results, plasma DDC activity does not appear to be a promising biomarker for TR in recent-onset psychosis patients who are already receiving antipsychotic treatment.

The impact of delay in clozapine initiation on treatment outcomes in patients with treatment-resistant schizophrenia: A systematic review

Approximately one-third of patients with schizophrenia have treatment-resistant schizophrenia (TR-SCZ), which is a condition characterized by suboptimal response to antipsychotics other than clozapine. Importantly, treatment with clozapine-the only antipsychotic with an indication for TR-SCZ-is often delayed, which could contribute to negative outcomes. Given that the specific impact of delay in clozapine initiation is not well understood, we aimed to conduct a systematic search of the Ovid Medline^® database to identify English language publications exploring the impact of delay in clozapine initiation on treatment outcomes in patients with TR-SCZ. Additionally, clinico-demographic factors associated with clozapine delay were examined. Our search identified four retrospective studies that showed an association between longer delay in clozapine initiation and poorer treatment outcomes, even after including covariates, such as age, sex, and duration of illness. In addition, we found six studies that showed an association between age and clozapine delay, but results with regard to other clinico-demographic variables were inconsistent. Overall, the available literature reveals a possible link between delay in clozapine use and poorer treatment outcomes in patients with TR-SCZ. However, given the relatively small number of studies on this clinically important topic, future research is warranted to draw more definitive conclusions.

Clozapine use in early psychosis

BACKGROUND

The superior efficacy of clozapine in treatment resistant schizophrenia has been clearly demonstrated, yet there are often delays in the commencement of clozapine. In this study, we aimed to determine; the proportion of young people with a first episode of psychosis (FEP) who would be considered eligible for clozapine treatment, the theoretical delay in commencing clozapine and to compare the outcomes of those treated with clozapine to those who were eligible but not treated with clozapine.

METHODS

This study was conducted at Orygen Youth Health (OYH), a youth mental health service for young people aged 15-24. All clients who were treated at the Early Psychosis Prevention and Intervention Centre (EPPIC) clinic between 01.01.2011 and 31.12.2013 were included.

RESULTS

544 young people presented with a FEP in the study period and 9.4% (N = 51) subsequently fulfilled criteria for treatment-resistant schizophrenia. Of these individuals, thirty (58.8%) were commenced on clozapine, in addition to a further eleven. The median delay to the commencement of clozapine was 42 weeks (I.Q.R. = 7.5-64). Of those commenced on clozapine, 76.6% achieved remission of positive psychotic symptoms and 50% were in employment or education by the time of discharge or transfer to the adult mental health services. The rate of discontinuation of clozapine was 24.4% and 60.0% of discontinuations were due to cardiac complications and the remainder were due to non-compliance.

CONCLUSIONS

These findings suggest that early intervention for psychosis services have a crucial role in ensuring timely initiation of clozapine in individuals with a diagnosis of treatment-resistant schizophrenia.

The critical treatment window of clozapine in treatment-resistant schizophrenia: Secondary analysis of an observational study

Previous studies have suggested that a delay in initiating clozapine is one of the predictors of outcomes in treatment-resistant schizophrenia (TRS). However, whether there is a critical treatment window of clozapine in TRS and the duration of that window remain unclear. We conducted a secondary analysis of a previously published observational study using a retrospective chart review of 105 patients with TRS who were treated with clozapine. We included 90 patients who remained on clozapine for at least 3 months. The delay in initiating clozapine was an independent contributor to symptomatic improvement based on treatment with clozapine by multiple linear regression analysis. A receiver operating characteristic curve analysis (area under the curve: 0.78) confirmed 2.8 years was the best predictive cut-off value of delay in initiating clozapine for responses in patients treated with clozapine (sensitivity: 0.66, specificity: 0.84). In patients with a delay in initiating clozapine of ≤2.8 years and a delay in initiating clozapine of >2.8 years, the response rates were 81.6% and 30.8% (risk ratio=2.65; 95% confidence interval, 1.80, 3.63), respectively. Clinicians should reduce the delay in initiating clozapine to less than 3 years to improve symptomatic outcomes in TRS and to prevent clozapine-resistant schizophrenia.