Maintenance Treatment With Antipsychotic Drugs in Schizophrenia: A Cochrane Systematic Review and Meta-analysis

Advancements in Non-Dopaminergic Treatments for Schizophrenia: A Systematic Review of Pipeline Developments

INTRODUCTION

Conventional antipsychotic drugs that attenuate dopaminergic neural transmission are ineffective in approximately one-third of patients with schizophrenia. This necessitates the development of non-dopaminergic agents.

METHODS

A systematic search was conducted for completed phase II and III trials of compounds for schizophrenia treatment using the US Clinical Trials Registry and the EU Clinical Trials Register. Compounds demonstrating significant superiority over placebo in the primary outcome measure in the latest phase II and III trials were identified. Collateral information on the included compounds was gathered through manual searches in PubMed and press releases.

RESULTS

Sixteen compounds were identified; four compounds (ulotaront, xanomeline/trospium chloride, vabicaserin, and roluperidone) were investigated as monotherapy and the remaining 12 (pimavanserin, bitopertin, BI 425809, encenicline, tropisetron, pregnenolone, D-serine, estradiol, tolcapone, valacyclovir, cannabidiol, and rimonabant) were examined as add-on therapy. Compared to the placebo, ulotaront, xanomeline/trospium chloride, vabicaserin, bitopertin, estradiol, cannabidiol, rimonabant, and D-serine showed efficacy for positive symptoms; roluperidone and pimavanserin were effective for negative symptoms; and encenicline, tropisetron, pregnenolone, tolcapone, BI 425809, and valacyclovir improved cognitive function.

DISCUSSION

Compounds that function differently from existing antipsychotics may offer novel symptom-specific therapeutic strategies for patients with schizophrenia.

Identification and treatment of individuals with childhood-onset and early-onset schizophrenia

Approximately 8 % of patients with schizophrenia are diagnosed before age 18, and 18 % experience their first symptoms before age 18. This narrative review explores the management of patients with early-onset schizophrenia (EOS) and childhood-onset schizophrenia (COS) from diagnosis to their transition to adult care settings. Early diagnosis of schizophrenia in children and adolescents is essential for improving outcomes, but delays are common due to overlapping of symptoms with developmental phenomena and other psychiatric conditions, including substance use, and lack of clinicians' awareness. Once diagnosed, antipsychotic treatment is key, with specific second-generation agents generally being preferred due to better tolerability and their broader efficacy evidence-base in youth. Dosing should be carefully individualized, considering age-related differences in drug metabolism and side effect liability. Clinicians must be vigilant in detecting early non-response and consider switching or dose escalation when appropriate. Since early age of illness onset is a consistent risk factor for treatment-resistant schizophrenia (TRS), clinicians need to be competent in diagnosing TRS and using clozapine. Since COS and EOS are associated with cognitive deficits and impaired functioning, psychosocial interventions should be considered to improve overall functioning and quality of life. Good long-term outcomes depend on continuous treatment engagement, and successful transitioning from pediatric to adult care requires careful planning, early preparation, and collaboration between pediatric and adult clinicians. Targeting functional outcomes and quality of life in addition to symptom remission can improve overall patient well-being. Comprehensive evaluations, age-specific assessments, and targeted interventions are needed to address the unique challenges of EOS and COS.

Effect of single-administration of D-sorbitol pretreatment on the bitterness and continued willingness to take asenapine: a randomized, single-blind, placebo-controlled, crossover trial

BACKGROUND

Asenapine has unique orally-related side effects, such as a bitter taste induced by sublingual administration, which often results in discontinuation of the medication. While the FDA has approved black-cherry-flavored asenapine, several countries have prescribed only unflavored versions. Specifically, Asians commonly report experiencing the bitterness of asenapine because they are more sensitive to bitter tastes than other ethnic groups. In this study, with the aim of improving adherence by reducing the bitterness of asenapine, we investigated the effects of D-sorbitol, which reduced the bitterness parameters of taste sensors in our previous basic study on the bitterness and continuity of asenapine among patients with schizophrenia.

METHODS

Twenty adult patients with schizophrenia were included in this single-blind, placebo-controlled, crossover trial. Participants rinsed their mouths with single-administration of D-sorbitol or a placebo prior to each administration of asenapine. We then conducted the questionnaires and assessed changes in the bitterness of asenapine (primary end point) and willingness to continue its use (secondary end point).

RESULTS

D-sorbitol significantly improved the bitterness of asenapine (p = 0.038). Although it did not significantly increase the willingness to continue asenapine (p = 0.180), it did show improvement over the placebo in enhancing willingness to continue, especially in patients who were not accustomed to its taste.

CONCLUSION

Our findings indicate that single-administration of D-sorbitol significantly reduces the bitterness of asenapine. In countries where flavored asenapine is not available, this finding could benefit patients who were not accustomed to its bitter taste.

TRIAL REGISTRATION

This study was registered in the Japan Registry of Clinical Trials (jRCTs041210019) on May 14, 2021.

Global Neuropsychopharmacological Prescription Trends in Adults with Schizophrenia, Clinical Correlates and Implications for Practice: A Scoping Review

It is important to examine the psychotropic prescription practices in schizophrenia, as it can inform regarding changing treatment choices and related patient profiles. No recent reviews have evaluated the global neuropsychopharmacological prescription patterns in adults with schizophrenia. A systematic search of the literature published from 2002 to 2023 found 88 empirical papers pertinent to the utilization of psychotropic agents. Globally, there were wide inter-country and inter-regional variations in the prescription of psychotropic agents. Overall, over time there was an absolute increase in the prescription rate of second-generation antipsychotics (up to 50%), mood stabilizers (up to 15%), and antidepressants (up to 17%), with an observed absolute decrease in the rate of antipsychotic polypharmacy (up to 15%), use of high dose antipsychotic (up to 12% in Asia), clozapine (up to 9%) and antipsychotic long-acting injectables (up to 10%). Prescription patterns were mainly associated with specific socio-demographic (such as age), illness (such as illness duration), and treatment factors (such as adherence). Further work, including more evidence in adjunctive neuropsychopharmacological treatments, pharmaco-economic considerations, and examination of cohorts in prospective studies, can proffer insights into changing prescription trends relevant to different treatment settings and predictors of such trends for enhancement of clinical management in schizophrenia.

An umbrella review of adverse effects associated with antipsychotic medications: the need for complementary study designs

Antipsychotic medications are widely prescribed in psychotic illnesses and other mental disorders. Effectiveness is well-established, particularly for reducing symptoms such as delusions and hallucinations, but can be impacted by tolerability. Adverse effects are wide-ranging, and vary between antipsychotics, which is clinically important. This umbrella review aimed to comprehensively summarise the extent and quality of evidence for adverse effects associated with antipsychotic use in people with mental disorders. We included 32 meta-analyses of randomised trials and observational studies. The overall robustness of reported associations was considered in terms of review quality, heterogeneity, excess significance bias, and prediction intervals. Using this approach, endocrine and metabolic, movement-related, and sedation and sleep problems were the clinical domains with strongest evidence. The overall quality of included meta-analyses was low, and individual adverse effects were not typically examined in meta-analyses of both randomised trials and observational study designs. Future reviews should focus on adhering to methodological guidelines, consider the complementary strengths of different study designs, and integrate clinically relevant information on absolute rates and severity of adverse effects.

Efficacy of transcranial alternating current stimulation for schizophrenia treatment: A systematic review

BACKGROUND

Transcranial alternating current stimulation (tACS) is an innovative noninvasive technique in brain stimulation that involves applying a low-intensity electrical current to the scalp. And increasing evidence has revealed its potential in schizophrenia treatment.

OBJECTIVE

This systematic review aimed to evaluate the efficacy of tACS as a novel neurostimulation technique for improving cognitive impairment and alleviating psychotic symptoms in schizophrenia. Additionally, this review attempted to explore the impact of stimulation parameters on the effectiveness of tACS treatment.

METHODS

A systematic literature search was conducted across five databases, including Web of Science, Embase, PubMed, CENTRAL, and PsycINFO, to identify studies investigating the use of tACS in schizophrenia. Only studies that involved the experimental use of tACS in patients with schizophrenia were included in this review.

RESULTS

Nineteen studies were included in this review. The most frequently used current intensities were 2 mA and 1 mA, and the most commonly used frequencies were alpha (10 Hz), theta (4.5 Hz and 6 Hz), and gamma (40 Hz). Some studies showed that tACS may have a potential therapeutic effect by improving cognitive functions in various cognitive domains and/or ameliorating negative symptoms, hallucinations, and delusions in patients with schizophrenia, while others showed no significant change. These studies also implicated that tACS treatment is safe and well tolerated.

CONCLUSIONS

Overall, this systematic review suggests that tACS has promise as a novel, effective, and adjunctive treatment approach for treating schizophrenia. Future research is needed to determine the optimal parameters of tACS for treating this complex disorder.

Implementing gradual, hyperbolic tapering of long-acting injectable antipsychotics by prolonging the inter-dose interval: an in silico modelling study

Gradual, hyperbolic tapering has been proposed as a method to reduce the risk of withdrawal effects and potential relapse of an underlying condition by minimising disruption of existing equilibria. We applied hyperbolic tapering principles in silico to long-acting aripiprazole to generate regimens for withdrawal in clinical practice. We derived thresholds for taper rates using existing studies and consensus. Using pharmacokinetic data for aripiprazole long-acting injectable antipsychotic (ALAI), we conducted in silico modelling to examine the impact of abrupt cessation of long-acting injectable antipsychotic (LAI) medication and the effect of prolonging inter-dose interval on plasma aripiprazole levels and consequent D2 occupancy. We also modelled transitions from LAI medication to oral medication. Regimens were designed to afford a rate of reduction between 5 and 12.5 percentage points of D2 occupancy per month. Abrupt discontinuation of ALAI was shown to lead to a maximal D2 occupancy reduction of 16.8 percentage points per month; prolongation of the inter-dose interval of ALAI produced a slower reduction. Specifically, hyperbolic tapering was afforded by prolongation of a 400 mg ALAI inter-dose interval from 4 to 7 weeks, before reducing the dose to 300 mg ALAI. This could then be administered at up to 4-week (for 6% maximal D2 occupancy change), 6-week (9% change) or 7-week (11% change) intervals. Switching to oral medication - 5, 2.5 and 1.25 mg for the three regimens, respectively - is required for ALAI to complete full cessation to prevent too rapid a reduction in D2 occupancy. Oral medication should probably be maintained at a consistent dose for 3-6 months before further reductions to account for residual LAI being concurrently eliminated. Hyperbolic dose tapering is possible with ALAI through prolongation of the inter-dose interval and may reduce the risk of relapse compared to abrupt discontinuation of LAI medication.

Sensory evaluation of the bitterness of asenapine using D-sorbitol pretreatment: single-blind, placebo-controlled, crossover trial

BACKGROUND

Antipsychotics are essential in the acute treatment of and maintenance therapy for schizophrenia, but medication adherence and long-term treatment continuity are needed to maximize their effectiveness. Each antipsychotic has various side effects, which may affect adherence. Some patients with schizophrenia are reluctant to take asenapine because of its unique oral-related side effects, such as the bitter taste caused by sublingual administration. Our previous basic research found that D-sorbitol lowered the bitterness parameters of the taste sensors. However, whether D-sorbitol has the same effect in patients remains unclear. Therefore, using a D-sorbitol solution, we aim to evaluate changes in the bitterness of asenapine among patients with schizophrenia.

METHODS

In this single-blind, placebo-controlled, crossover trial, we plan to recruit 20 adult patients with schizophrenia spectrum disorder who take sublingual asenapine tablets. The participants will be divided into two groups (n = 10 each). Each group will be given a D-sorbitol or placebo solution on the first day for rinsing before taking the sublingual asenapine tablets. After a 1-day interval, the participants will rinse their mouths again with a different liquid. Questionnaires regarding changes in taste and the willingness to continue asenapine will be conducted before the start of the study and after each rinse. The primary and secondary end points will be a taste evaluation of bitterness, and the willingness to continue asenapine, respectively. Differences in questionnaire scores between the D-sorbitol and placebo solutions will be calculated and analyzed using a McNemar test.

DISCUSSION

This study aims to determine the efficacy of D-sorbitol in masking the bitter taste of asenapine. To our knowledge, it is the first intervention study using D-sorbitol for bitter taste of asenapine in patients with schizophrenia. Evidence of the efficacy of D-sorbitol could result in D-sorbitol pretreatment being an easy and inexpensive means of improving adherence to asenapine.

TRIAL REGISTRATION

This study was registered in the Japan Registry of Clinical Trials jRCTs041210019, on May 14, 2021. Ethics approval was obtained from the Nagoya University Clinical Research Review Board.