Pharmacological and nonpharmacological augmentation treatments for clozapine-resistant schizophrenia: A systematic review and network meta-analysis with normalized entropy assessment

Effectiveness of clozapine augmentation with specific doses of other antipsychotics in schizophrenia: a meta-analysis from two nationwide cohorts

Although clozapine is the most effective medication for treatment-resistant schizophrenia, response is inadequate in over half of people with that condition. There is limited guidance available on effective clozapine augmentation strategies. We studied the comparative effectiveness of specific doses of oral olanzapine, quetiapine, risperidone and aripiprazole augmentation of clozapine treatment on the risk of hospitalization due to a psychotic episode, as a marker for severe relapse, among patients with schizophrenia or schizoaffective disorder. In this population-based study, patients with one of those diagnoses receiving clozapine were identified from Finnish (years 1995-2017, N=14,053) and Swedish (years 2006-2021, N=8,743) nationwide registers. The risk of hospitalization due to a psychotic episode associated with periods of antipsychotic augmentation of clozapine treatment vs. same-dose clozapine monotherapy was assessed by a within-individual design, using each individual as his/her own control to eliminate selection bias, and analyzed with stratified Cox models. The two national cohorts were first analyzed separately; then results were combined using a random-effect meta-analysis. Secondary outcomes were somatic hospitalization, and hospitalization for psychosis or a somatic cause. The only augmentation associated with a significantly decreased risk of hospitalization due to psychosis in both countries was medium-dose (9 to <16.5 mg/day) aripiprazole combined with high-dose (≥330 mg/day) clozapine, and this combination was associated with the best outcome in the meta-analysis (adjusted hazard ratio, aHR=0.68, 95% CI: 0.62-0.75, p<0.0001). Among patients using medium-dose (180 to <330 mg/day) clozapine, medium-dose aripiprazole augmentation was the only treatment more effective than clozapine monotherapy after Bonferroni correction (aHR=0.79, 95% CI: 0.70-0.91, p=0.0006). The use of all high-dose augmentations was associated with an increased risk of hospitalization due to psychosis. Only aripiprazole augmentations were associated with a decreased risk of hospitalization for psychosis or a somatic cause, and the lowest risk was observed for medium-dose aripiprazole plus high-dose clozapine (aHR=0.70, 95% CI: 0.58-0.84, p=0.0001). This meta-analysis of two nationwide cohorts, totaling almost 23,000 patients using clozapine, indicates that medium-dose aripiprazole augmentation of clozapine treatment is associated with a 20-30% decreased risk of severe relapse compared with clozapine monotherapy within the same individuals, while augmentation with higher doses of aripiprazole (as well as with high doses of all other antipsychotics) is associated with an increased relapse risk.

Clozapine is a functional antagonist at cardiac human H2-histamine receptors

Clozapine is an atypical antipsychotic (neuroleptic) drug. Clozapine binds to H2-histamine receptors in vitro. We wanted to test the hypothesis that clozapine might be a functional antagonist at human cardiac H2-histamine receptors. To that end, we studied isolated electrically stimulated left atrial preparations and spontaneously beating right atrial preparations from transgenic mice with cardiomyocyte-specific overexpression of the human H2-histamine receptor (H2-TG). For comparison, we used wild-type littermate mice (WT). Finally, we measured isometric force of contraction in isolated electrically stimulated muscle strips from the human right atrium (HAP) obtained from patients during bypass surgery. After pre-stimulation with histamine, clozapine (up to 10 µM) concentration and time dependently decreased beating rate in right atrial preparations from H2-TG. Clozapine concentration dependently 1, 3, and 10 µM decreased histamine-stimulated force of contraction in HAP. Clozapine (10 µM) decreased also the isoprenaline-stimulated force of contraction in HAP. In summary, clozapine can antagonize the function of H2-histamine and β-receptors in the human heart.

Pharmacologic Augmentation of Computerized Auditory Training in Chronic Psychosis: Preliminary Findings From a Single-Site, Double-Blind Study

BACKGROUND

Computerized auditory training (AT) modestly improves symptoms, cognition, and functioning in schizophrenia. We assessed whether d-amphetamine (AMPH) or memantine (MEM) can enhance gains from 30-h of AT.

METHODS

Antipsychotic-medicated individuals with chronic psychosis (n = 68; mean age 47.03y; M:F = 39:29) completed up to 30 AT sessions (2-3/week; n = 50 completed 30 sessions) in 3 groups: "AMPH group" (AMPH (5 mg po) 1-h before each AT session); "MEM group" (titrated to 10 mg MEM bid and maintained that dose throughout training); "PBO group" (PBO dosed identically to either AMPH or MEM). Primary (PANSS total, MCCB Composite, WHODAS) and secondary (PANSS positive, PANSS negative, YMRS, PHQ-9, PSYRATS) outcome measures were acquired at baseline, after 10, 20, and 30 AT sessions, and 12 weeks post-training. Pill identity (active/PBO) was blind to subjects and staff.

RESULTS

Marginally significant between-group gains for AMPH vs PBO were detected for one of three primary outcomes (WHODAS, P =.050; but not PANSS total or MCCB Composite), and for 3 of 5 secondary clinical outcomes (PANSS positive, YMRS, PSYRATS, P's≤.027-.049). Within-subject gains over time were detected for primary and secondary clinical measures for AMPH (P's≤.014-.004) and MEM (P's≤.02-.001) groups; some of these would not survive conservative correction for multiple comparisons. No measures detected symptom worsening; treatment satisfaction exceeded subjects' expectations.

CONCLUSIONS

Results are mixed; drug-associated gains in several measures vs PBO suggest that these regimens may augment AT-induced functional and clinical improvement in psychosis patients, independent of changes in neurocognition. Assessment in larger samples seems warranted.

Electroconvulsive Therapy in Forensic Psychiatry: A Systematic Review

ABSTRACT

Patients with schizophrenia are the largest population in forensic hospitals, and treatment-resistant psychosis is associated with length of stay. For patients with severe and treatment-resistant psychotic disorders, electroconvulsive therapy (ECT) is a potentially effective treatment. Data regarding the use of ECT in forensic psychiatry are scarce. This systematic review aims to provide an overview of the use of ECT in forensic psychiatry. Three databases (PubMed, Web of Science, and PsycINFO) were searched for publications since 1980. Peer-reviewed articles describing patients who underwent ECT treatment in the context of forensic psychiatry were included when a treatment outcome was reported. We identified 5 case reports and 1 case series comprising 13 patients treated with ECT in forensic settings. The quality of evidence was poor accompanied by a considerable risk of bias. Patients were diagnosed with schizophrenia spectrum disorders (n = 10) or depression with psychotic features (n = 3). Eleven patients (84.6%) were described as responders in terms of symptom improvement associated with a reduction of aggressive behavior and improved functioning. At least 3 patients were able to return to community settings. Despite the very limited evidence base, our review suggests that patients in forensic hospitals may benefit from ECT, but more systematic and higher-quality evidence is urgently needed. In addition to prospective, controlled observational studies, a qualitative view focusing on patients' perspectives in this specific setting is of particular importance.

Effect of comprehensive intervention model based on drug-psychology-society-skills on medication compliance and cognitive ability of chronic schizophrenia patients

BACKGROUND

The intervention value of a drug-psycho-social-skill model on medication compliance and cognitive ability in patients with chronic schizophrenia was unknown.

AIM

To explore the intervention value of a drug-psycho-social-skill model on medication compliance and cognitive ability in patients with chronic schizophrenia.

METHODS

Overall, 98 out-patients and in-patients with chronic schizophrenia treated in our hospital from February 2022 to January 2023 were included and randomly divided into the study (50 patients) and control groups (48 patients). For 3 months, the control group was treated with conventional drugs, and the research group with a comprehensive intervention model of drug-psychology-society-skills. Data were obtained for the mini mental assessment scale (MMSE), Montreal cognitive assessment scale (MoCA), positive and negative symptom scale, insight and treatment attitude scale, cognitive ability scale and social skills [personal and social function scale (PSP)]. The adverse reactions were observed.

RESULTS

After the intervention, the MMSE and MoCA scores improved in both groups. MoCA scores in the study group (26.58 ± 3.21) were significantly (P < 0.05) higher than those in the control group (24.68 ± 3.02), MMSE scores were not significantly higher. Post-intervention, positive and negative symptom scores improved in both groups, and the positive and negative symptom scores in the study group [(12.01 ± 2.58) and (32.51 ± 2.11)] were significantly (P < 0.05) different than those in the control group [(14.54 ± 2.33) and (33.74 ± 2.55)]. Post-intervention, insight and treatment attitudes questionnaire scores of both groups were improved and compared with the control group (7.97 ± 3.02), the study group (13.56 ± 6.35) had significantly (P < 0.05) higher scores. Post-intervention, the MATRICS consensus cognitive battery score of both groups was improved and compared with the control group (38.44 ± 6.23), the score of the study group was significantly (P < 0.05) increased (43.51 ± 6.01). Post-intervention, the PSP score of the study group (78.38 ± 6.63) was significantly (P < 0.05) higher than that of the control group (74.52 ± 7.01). During the intervention period, the incidence of adverse reactions in the study group was 6.25%, not significantly different from that in the control group (8.33%). During the intervention, both groups experienced adverse reactions, with no significant difference between groups (P > 0.05).

CONCLUSION

The comprehensive intervention model based on drug-psychology-society-skills has obvious intervention effects on patients with chronic schizophrenia, which improves their cognitive ability and reduces their positive and negative symptoms. Simultaneously, it improves the self-knowledge of patients, improves their attitude toward treatment, effectively promotes the recovery of patients' social functions, and is safe. Therefore, it is worthy of being vigorously promoted and widely used in clinics.

Schizophrenia and Bone Marrow Disorders: An Emerging Clinical Association

Schizophrenia is a chronic psychiatric disorder with a complex etiology involving genetic, neurobiological, and environmental factors. Many individuals with schizophrenia experience treatment resistance despite advances in pharmacologic and non-pharmacologic interventions. Immune dysregulation, characterized by altered cytokine levels, immune-related gene expression, and neuroinflammation, plays a critical role in schizophrenia's pathogenesis. Furthermore, associations between schizophrenia and bone marrow malignancies, with documentation of remission of treatment-resistant schizophrenia following bone marrow transplantation for malignancies, are emerging. This review synthesizes findings on the immunological underpinnings of schizophrenia, explores potential connections with bone marrow dysfunction, and evaluates the therapeutic potential of immune-modulating approaches, including bone marrow transplantation. By highlighting these connections, the study aims to advance understanding and stimulate prospective research into innovative treatments for this debilitating condition.

Theta Burst Stimulation Protocols for Schizophrenia: A Systematic Review and Network Meta-Analysis

Importance

To date, several theta burst stimulation (TBS) protocols, such as intermittent TBS (iTBS), have been proposed; however, previous systematic reviews have revealed inconsistent efficacy findings in individual TBS studies for schizophrenia.

Objective

To examine which TBS protocols are associated with the most favorable and acceptable outcomes in adults with schizophrenia.

Data Sources

The Cochrane Library, PubMed, and Embase databases were searched for studies published before May 22, 2024.

Study Selection

The inclusion criteria were as follows: (1) published and unpublished randomized clinical trials (RCTs) of any TBS treatment and (2) RCTs including individuals with schizophrenia spectrum disorders, other psychotic disorders, or both.

Data Extraction and Synthesis

This study followed the Cochrane standards for data extraction and data quality assessment and used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline for reporting. The risk of bias of individual studies was assessed using the second version of the Cochrane risk of bias tool, and the Confidence in Network Meta-Analysis application was used to rate the certainty of evidence for meta-analysis results. At least 2 authors double-checked the literature search, data transfer accuracy, and calculations.

Main Outcomes and Measures

The primary outcome of this study was improvement in scores related to negative symptoms. Our frequentist network meta-analysis used a random-effects model. The standardized mean difference (SMD) or odds ratio for continuous or dichotomous variables, respectively, was calculated with 95% CIs.

Results

A total of 30 RCTs of 9 TBS protocols, with 1424 participants, were included. Only iTBS over the left dorsolateral prefrontal cortex (L-DLPFC) was associated with reduced negative symptom scores (SMD, -0.89; 95% CI, -1.24 to -0.55), overall symptom scores (SMD, -0.81; 95% CI, -1.15 to -0.48), Positive and Negative Syndrome Scale general subscale scores (SMD, -0.57; 95% CI, -0.89 to -0.25), depressive symptom scores (SMD, -0.70; 95% CI, -1.04 to -0.37), and anxiety symptom scores (SMD, -0.58; 95% CI, -0.92 to -0.24) and improved overall cognitive impairment scores (SMD, -0.52; 95% CI, -0.89 to -0.15) compared with a sham. However, positive symptom score changes, all-cause discontinuation rate, discontinuation rate due to adverse events, headache incidence, and dizziness incidence did not significantly differ between any TBS protocols and sham.

Conclusions and Relevance

In this network meta-analysis, iTBS over the L-DLPFC was associated with improved scores for negative, depressive, anxiety, and cognitive symptoms in individuals with schizophrenia and was well tolerated by the participants. Other forms of TBS were not associated with benefit. Further research is needed to assess the potential role of TBS in the treatment of schizophrenia.

Overcoming the barriers to identifying and managing treatment-resistant schizophrenia and to improving access to clozapine: A narrative review and recommendation for clinical practice

Clozapine is the only approved antipsychotic for treatment-resistant schizophrenia (TRS). Although a large body of evidence supports its efficacy and favorable risk-benefit ratio in individuals who have failed two or more antipsychotics, clozapine remains underused. However, variations in clozapine utilization across geographic and clinical settings suggest that it could be possible to improve its use. In this narrative review and expert opinion, we summarized information available in the literature on the mechanisms of action, effectiveness, and potential adverse events of clozapine. We identified barriers leading to discouragement in clozapine prescription internationally, and we proposed practical solutions to overcome each barrier. One of the main obstacles identified to the use of clozapine is the lack of appropriate training for physicians: we highlighted the need to develop specific professional programs to train clinicians, both practicing and in residency, on the relevance and efficacy of clozapine in TRS treatment, initiation, maintenance, and management of potential adverse events. This approach would facilitate physicians to identify eligible patients and offer clozapine as a treatment option in the early stage of the disease. We also noted that increasing awareness of the benefits of clozapine among healthcare professionals, people with TRS, and their caregivers can help promote the use of clozapine. Educational material, such as leaflets or videos, could be developed and distributed to achieve this goal. The information provided in this article may be useful to improve disease burden and support healthcare professionals, patients, and caregivers navigating the complex pathways to TRS management.

Randomized, double-blind, sham-controlled trial to evaluate the efficacy and tolerability of electroconvulsive therapy in patients with clozapine-resistant schizophrenia

There is no established treatment for patients with clozapine-resistant schizophrenia (CRS). Clozapine augmentation strategies with antipsychotics or others substances are effective in comparison with placebo while and Electroconvulsive therapy (ECT) showed to be effective in comparison with treatment as usual (TAU) but not with placebo (sham-ECT). In the present double- blind randomized controlled trial, we compared 40 outpatients who received 20 sessions of ECT (n = 21) or sham-ECT (n = 19) (age = 37.40 ± 9.62, males = 77.5 %, illness duration = 14.95 ± 8.32 years, mean total Positive and Negative Syndrome Scale (PANSS) = 101.10 ± 24.91) who fulfilled well-defined CRS criteria including baseline clozapine plasma levels ≥350 ng/mL. The primary outcome was the ≥50 % PANSS Total Score reduction; secondary outcomes were the scores of the PANSS subscales, PANSS five-factor dimensions, PANSS-6 and the Calgary Depression Rating Scale (CDRS). Treatment response was analyzed by percentage reduction, Linear Mixed Models and effect sizes. At baseline both groups showed no differences except for years of school education (included as a covariate). At endpoint, only 1/19 of the completers (5.26 %) in the ECT group and 0/17 in the sham-ECT group showed a ≥50 % total PANSS score reduction. Both groups showed no significant differences of the total PANSS score (F = 0.12; p = 0.73), Positive (F = 0.27, p = 0.61), Negative (F = 0.25, p = 0.62), and General Psychopathology scores (F = 0.01, p = 0.94) as well for all PANSS five factors, the PANSS-6 and CDRS. Thus, the present study found no evidence that ECT is better than Sham-ECT in patients with CRS. Future sham-ECT controlled studies with larger sample sizes are warranted to test the efficacy of ECT for patients with CRS.

Optimizing antidepressant and clozapine co-prescription in clinical practice: A systematic review and expert recommendations

OBJECTIVES

To synthesize the information relevant for clinical practice on clozapine-antidepressant co-prescription concerning pharmacokinetic drug-drug interactions (DDI), adverse drug reactions (ADRs) associated with the co-prescription, antidepressant add-on for clozapine-resistant symptoms and antidepressant add-on for clozapine-induced ADRs.

METHODS

Articles were identified with MEDLINE, Web of Sciences and PsycINFO search from inception through April 2023. Data were synthesized narratively.

RESULTS

ADRs are most often induced by the co-prescription of antidepressants that inhibit CYP enzymes (fluvoxamine, fluoxetine, paroxetine). Fluvoxamine add-on is hazardous because of its potent inhibition of clozapine metabolism and has few indications (lowering daily number of clozapine tablets, reducing norclozapine-induced metabolic disturbances and other dose-dependent clozapine-induced ADRs). ADR frequency may be reduced by therapeutic drug monitoring and knowledge of other factors impacting clozapine metabolism (pneumonia, inflammation, smoking, etc.). Improvement of negative symptoms is the most documented beneficial effect of antidepressant add-on for clozapine-resistant psychotic symptoms. The add-on antidepressant should be chosen according to its safety profile regarding DDI with clozapine: antidepressants inhibiting clozapine metabolism or increasing the anticholinergic load should be avoided. Other indications of antidepressant add-on (affective or obsessive compulsive symptoms, sialorrhea, and enuresis) are poorly documented.

CONCLUSION

Antidepressant add-on to clozapine is associated with potential benefits in clozapine users as this strategy may contribute to reduce the burden of clozapine-resistant symptoms or of clozapine-induced ADRs. Further studies are needed to determine whether antidepressant add-on can reduce the risk of clozapine discontinuation.

Examining the clinical effectiveness of continuation and maintenance electroconvulsive therapy in schizophrenia

OBJECTIVE

There are few studies that examine the effectiveness of Continuation/Maintenance Electroconvulsive Therapy (C/M-ECT) in schizophrenia, despite the documented effectiveness of acute ECT treatment. We aimed to investigate the clinical effectiveness of C/M-ECT for in-patients with Schizophrenia in a naturalistic setting. We examined the medical records of 46 in-patients who were diagnosed with Schizophrenia and had received C/M-ECT belonging to non-acute extended care service in a public psychiatry hospital in Sydney, Australia. The focus of analysis was on 138 treatment cycles (71 acute only cycles and 67 acute-continuation/maintenance cycles) across 45 subjects. A linear mixed effects model was used to describe the change in clinical global impression-severity (CGI-S) over time 4 time points viz., pre-post acute and pre-post continuation/maintenance ECT.

RESULTS

Acute-only cycles and acute-continuation/maintenance cycles had identical pre- (M = 5, C.I. = 4-6), post-cycle CGI-S scores, and identical CGI-S difference scores (M = 0, C.I. = -1 - 1). Broadly in each continuation/maintenance cycle, we observed an initial sharp decrease in CGI-S scores followed by a logarithmic increase in scores over time, with satisfactory CGI-S score maintenance observed for approximately 6 months. Bitemporal ECT influenced CGI-S across maintenance ECT (p < 0.05) indicating smaller declines in CGI-S scores over time.

CONCLUSION

In schizophrenia, C/M ECT preserves effects on illness severity for at least upto 6 months following an acute course of ECT. Bitemporal ECT vis a vis other electrode positions differentiated clinical severity over time.

The schizophrenia syndrome, circa 2024: What we know and how that informs its nature

With new data about different aspects of schizophrenia being continually generated, it becomes necessary to periodically revisit exactly what we know. Along with a need to review what we currently know about schizophrenia, there is an equal imperative to evaluate the construct itself. With these objectives, we undertook an iterative, multi-phase process involving fifty international experts in the field, with each step building on learnings from the prior one. This review assembles currently established findings about schizophrenia (construct, etiology, pathophysiology, clinical expression, treatment) and posits what they reveal about its nature. Schizophrenia is a heritable, complex, multi-dimensional syndrome with varying degrees of psychotic, negative, cognitive, mood, and motor manifestations. The illness exhibits a remitting and relapsing course, with varying degrees of recovery among affected individuals with most experiencing significant social and functional impairment. Genetic risk factors likely include thousands of common genetic variants that each have a small impact on an individual's risk and a plethora of rare gene variants that have a larger individual impact on risk. Their biological effects are concentrated in the brain and many of the same variants also increase the risk of other psychiatric disorders such as bipolar disorder, autism, and other neurodevelopmental conditions. Environmental risk factors include but are not limited to urban residence in childhood, migration, older paternal age at birth, cannabis use, childhood trauma, antenatal maternal infection, and perinatal hypoxia. Structural, functional, and neurochemical brain alterations implicate multiple regions and functional circuits. Dopamine D-2 receptor antagonists and partial agonists improve psychotic symptoms and reduce risk of relapse. Certain psychological and psychosocial interventions are beneficial. Early intervention can reduce treatment delay and improve outcomes. Schizophrenia is increasingly considered to be a heterogeneous syndrome and not a singular disease entity. There is no necessary or sufficient etiology, pathology, set of clinical features, or treatment that fully circumscribes this syndrome. A single, common pathophysiological pathway appears unlikely. The boundaries of schizophrenia remain fuzzy, suggesting the absence of a categorical fit and need to reconceptualize it as a broader, multi-dimensional and/or spectrum construct.

Cariprazine augmentation of clozapine in schizophrenia-a retrospective chart review

The aim of our study was to evaluate the efficacy of cariprazine augmentation of clozapine in treatment-resistant schizophrenia in a retrospective chart review. Among 916 medical records of schizophrenia patients, we identified 12 individuals treated with a combination of those drugs for a duration of 3-60 weeks [median 32 (10-40)]. Clinical Global Impression-Improvement (CGI-I) scores were used to measure the treatment response between the introduction of cariprazine augmentation of clozapine and the last point of observation. The majority of the patients presented treatment response (9/12 patients, 75%) after 4-16 weeks of therapy [median 6 (4-12)]. Treatment was associated with the decrease in positive, negative, affective, and anxiety symptom severity, as well as improvement of patient global functioning. One patient discontinued the treatment due to side effects (akathisia), and two patients halted the therapy due to the exacerbation of psychotic symptoms. Our study presents a thorough clinical description of the largest number of treatment-resistant schizophrenia patients medicated using cariprazine augmentation of clozapine in a "real-world" setting. Our results suggest that the use of this combination may lead to the improvement in a broad range of symptoms of patients with this condition.

Lurasidone Augmentation of Clozapine in Schizophrenia—Retrospective Chart Review

The aim of our study was to evaluate the effectiveness of lurasidone augmentation of clozapine in treatment-resistant schizophrenia (SZ) in a retrospective chart review. From the medical records of 916 SZ patients, we identified 16 individuals treated with a combination of clozapine and lurasidone. The detailed clinical data are described separately for each patient. We compared the Clinical Global Impression—Severity (CGI-S) scores between three points of observation: before the treatment and one month and two months after its initiation. CGI Improvement (CGI-I) scores were used to evaluate the treatment response between the first and last points of observation. The vast majority of patients (14/16, 87.5%) responded to lurasidone augmentation of clozapine (CGI-I scores 1 or 2). Therapeutic effects were observable after 3–12 weeks of treatment (median 6 (4–6)). A reduction in CGI-S scores was observed after the first month of observation. There was an observable reduction in positive, depressive and anxiety symptoms, as well as an improvement in psychosocial functioning. Two patients discontinued treatment due to side effects. Our study suggests that lurasidone augmentation of clozapine may lead to improvements in a broad range of SZ symptom dimensions.