Treatment-resistant schizophrenia characterised by dopamine supersensitivity psychosis and efficacy of asenapine

Predictors of continuation for asenapine from real-world data in patients with schizophrenia

BACKGROUND

The continuation rates of pharmacotherapy in schizophrenia exhibit variability, a phenomenon influenced by the specific antipsychotic agent prescribed and patient-related factors such as age and duration of illness. In this context, our study aims to elucidate the predictors of medication continuation for asenapine sublingual tablets, characterized by unique formulation properties.

METHODS

Our investigation leveraged real-world data collected through post-marketing surveillance in Japan, comprising 3236 cases. Utilizing multivariate logistic regression analysis, we identified patient-related factors associated with medication continuation as the primary outcome measure, subsequently employing survival analysis for further evaluation. Additionally, adverse event occurrence was assessed as a secondary outcome measure.

RESULTS

Multivariate logistic regression analysis unveiled significant predictors of asenapine continuation, notably including patient-related factors such as a chlorpromazine equivalent dose exceeding 600 mg/day and an illness duration of 25 years or more. While the overall continuation rate stood at 40.6%, patients exhibiting factors such as a chlorpromazine equivalent dose surpassing 600 mg/day or an illness duration exceeding 25 years demonstrated continuation rates of 46.3% and 47.9%, respectively. Remarkably, patients presenting both factors showcased the highest continuation rate at 52.5%.

CONCLUSIONS

Our findings shed light on distinct patient-related predictors of asenapine continuation, deviating from those observed with other antipsychotic medications. This underscores the necessity of recognizing that predictive factors for antipsychotic medication continuation vary across different agents. Moving forward, elucidating these predictive factors for various antipsychotic medications holds paramount importance in schizophrenia treatment, facilitating the delivery of tailored therapeutic interventions for individual patients.

Epigenetic Targets in Schizophrenia Development and Therapy

Schizophrenia is regarded as a neurodevelopmental disorder with its course progressing throughout life. However, the aetiology and development of schizophrenia are still under investigation. Several data suggest that the dysfunction of epigenetic mechanisms is known to be involved in the pathomechanism of this mental disorder. The present article revised the epigenetic background of schizophrenia based on the data available in online databases (PubMed, Scopus). This paper focused on the role of epigenetic regulation, such as DNA methylation, histone modifications, and interference of non-coding RNAs, in schizophrenia development. The article also reviewed the available data related to epigenetic regulation that may modify the severity of the disease as a possible target for schizophrenia pharmacotherapy. Moreover, the effects of antipsychotics on epigenetic malfunction in schizophrenia are discussed based on preclinical and clinical results. The obtainable data suggest alterations of epigenetic regulation in schizophrenia. Moreover, they also showed the important role of epigenetic modifications in antipsychotic action. There is a need for more data to establish the role of epigenetic mechanisms in schizophrenia therapy. It would be of special interest to find and develop new targets for schizophrenia therapy because patients with schizophrenia could show little or no response to current pharmacotherapy and have treatment-resistant schizophrenia.

Efficacy of Asenapine in Drug-resistant Psychotic Patients with Dopamine Supersensitivity Psychosis: Two Cases

Dopamine supersensitivity psychosis (DSP) is an unstable clinical condition observed in individuals with schizophrenia who have been treated with an antipsychotic medication at a high dosage and/or for a long period. An up-regulation of dopamine D2 receptors (DRD2) is thought to be involved in the essential pathology of DSP. An antipsychotic agent with both tight binding to DRD2 and a long half-life is generally effective for treating DSP, but a patient who meets the criteria of treatment-resistant schizophrenia sometimes needs treatment with clozapine. We report the case details of two patients whose DSP was not controlled with several antipsychotics but was successfully controlled with asenapine. Asenapine binds to a broad range of dopamine receptors and serotonin receptors, and it is thus distinct from other atypical antipsychotics. The unique profile of asenapine may contribute to the control of severe DSP symptoms in individuals with schizophrenia.

Cytokine Imbalance as a Biomarker of Treatment-Resistant Schizophrenia

Treatment-resistant schizophrenia (TRS) is an important and unresolved problem in biological and clinical psychiatry. Approximately 30% of cases of schizophrenia (Sch) are TRS, which may be due to the fact that some patients with TRS may suffer from pathogenetically “non-dopamine” Sch, in the development of which neuroinflammation is supposed to play an important role. The purpose of this narrative review is an attempt to summarize the data characterizing the patterns of production of pro-inflammatory and anti-inflammatory cytokines during the development of therapeutic resistance to APs and their pathogenetic and prognostic significance of cytokine imbalance as TRS biomarkers. This narrative review demonstrates that the problem of evaluating the contribution of pro-inflammatory and anti-inflammatory cytokines to maintaining or changing the cytokine balance can become a new key in unlocking the mystery of “non-dopamine” Sch and developing new therapeutic strategies for the treatment of TRS and psychosis in the setting of acute and chronic neuroinflammation. In addition, the inconsistency of the results of previous studies on the role of pro-inflammatory and anti-inflammatory cytokines indicates that the TRS biomarker, most likely, is not the serum level of one or more cytokines, but the cytokine balance. We have confirmed the hypothesis that cytokine imbalance is one of the most important TRS biomarkers. This hypothesis is partially supported by the variable response to immunomodulators in patients with TRS, which were prescribed without taking into account the cytokine balance of the relation between serum levels of the most important pro-inflammatory and anti-inflammatory cytokines for TRS.

Childhood traumatic events and the dopaminergic theory of psychosis: A mini-review of studies investigating gene – environment interactions

There is great body of evidence showing a relationship between childhood adversity and psychosis onset. Genetic factors moderate the association between childhood adversity and psychosis risk potentially by influencing biological and/or psychological reaction following exposure to adversity. In this review, we discuss studies identifying the specific genetic variants known to affect dopamine levels involved in this interaction. Our review shows that the catechol-O-methyltransferase (COMT), dopamine D2 receptor (DRD2), AKT1 gene play a key role in mediating the relationship between childhood adversity and development of psychosis. We have also found conflicting findings on the impact of dopamine genes on the relationship between childhood adversity and development of psychosis, suggesting that other genetic and environmental factors should be taken into account. We here discuss the implications of our findings and future directions.

The Influence of Long-Term Treatment with Asenapine on Liver Cytochrome P450 Expression and Activity in the Rat. The Involvement of Different Mechanisms

Therapy of schizophrenia requires long-term treatment with a relevant antipsychotic drug to achieve a therapeutic effect. The aim of the present study was to investigate the influence of prolonged treatment with the atypical neuroleptic asenapine on the expression and activity of rat cytochrome P450 (CYP) in the liver. The experiment was carried out on male Wistar rats. Asenapine (0.3 mg/kg s.c.) was administered for two weeks. The levels of CYP mRNA protein and activity were determined in the liver and hormone concentrations were measured in the pituitary gland and blood serum. Asenapine significantly decreased the activity of CYP1A (caffeine 8-hydroxylation and 3-N-demethylation), CYP2B, CYP2C11 and CYP3A (testosterone hydroxylation at positions 16β; 2α and 16α; 2β and 6β, respectively). The neuroleptic did not affect the activity of CYP2A (testosterone 7α-hydroxylation), CYP2C6 (warfarin 7-hydroxylation) and CYP2E1 (chlorzoxazone 6-hydroxylation). The mRNA and protein levels of CYP1A2, CYP2B1, CYP2C11 and CYP3A1 were decreased, while those of CYP2B2 and CYP3A2 were not changed. Simultaneously, pituitary level of growth hormone-releasing hormone and serum concentrations of growth hormone and corticosterone were reduced, while that of triiodothyronine was enhanced. In conclusion, chronic treatment with asenapine down-regulates liver cytochrome P450 enzymes, which involves neuroendocrine mechanisms. Thus, chronic asenapine treatment may slow the metabolism of CYP1A, CYP2B, CYP2C11 and CYP3A substrates (steroids and drugs). Since asenapine is metabolized by CYP1A and CYP3A, the neuroleptic may inhibit its own metabolism, therefore, the plasma concentration of asenapine in patients after prolonged treatment may be higher than expected based on a single dose.