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High-impact rare genetic variants in severe schizophrenia.

Extreme phenotype sequencing has led to the identification of high-impact rare genetic variants for many complex disorders but has not been applied to studies of severe schizophrenia. We sequenced 112 individuals with severe, extremely treatment-resistant schizophrenia, 218 individuals with typical schizophrenia, and 4,929 controls. We compared the burden of rare, damaging missense and loss-of-function variants between severe, extremely treatment-resistant schizophrenia, typical schizophrenia, and controls across mutation intolerant genes. Individuals with severe, extremely treatment-resistant schizophrenia had a high burden of rare loss-of-function (odds ratio, 1.91; 95% CI, 1.39 to 2.63; P = 7.8 × 10-5) and damaging missense variants in intolerant genes (odds ratio, 2.90; 95% CI, 2.02 to 4.15; P = 3.2 × 10-9). A total of 48.2% of individuals with severe, extremely treatment-resistant schizophrenia carried at least one rare, damaging missense or loss-of-function variant in intolerant genes compared to 29.8% of typical schizophrenia individuals (odds ratio, 2.18; 95% CI, 1.33 to 3.60; P = 1.6 × 10-3) and 25.4% of controls (odds ratio, 2.74; 95% CI, 1.85 to 4.06; P = 2.9 × 10-7). Restricting to genes previously associated with schizophrenia risk strengthened the enrichment with 8.9% of individuals with severe, extremely treatment-resistant schizophrenia carrying a damaging missense or loss-of-function variant compared to 2.3% of typical schizophrenia (odds ratio, 5.48; 95% CI, 1.52 to 19.74; P = 0.02) and 1.6% of controls (odds ratio, 5.82; 95% CI, 3.00 to 11.28; P = 2.6 × 10-8). These results demonstrate the power of extreme phenotype case selection in psychiatric genetics and an approach to augment schizophrenia gene discovery efforts.

Aged

The time has come for revising the rules of clozapine blood monitoring in Europe. A joint expert statement from the European Clozapine Task Force.

The European Clozapine Task Force is a group of psychiatrists and pharmacologists practicing in 18 countries under European Medicines Agency (EMA) regulation, who are deeply concerned about the underuse of clozapine in European countries. Although clozapine is the most effective antipsychotic for people with treatment-resistant schizophrenia, a large proportion of them do not have access to this treatment. Concerns about clozapine-induced agranulocytosis and stringent blood monitoring rules are major barriers to clozapine prescribing and use. There is a growing body of evidence that the incidence of clozapine-induced agranulocytosis is very low after the first year of treatment. Maintaining lifelong monthly blood monitoring after this period contributes to unjustified discontinuation of clozapine. We leverage recent and replicated evidence on the long-term safety of clozapine to call for the revision and updating of the EMA's blood monitoring rules, thus aiming to overcome this major barrier to clozapine prescribing and use. We believe the time has come for relaxing the rules without increasing the risks for people using clozapine in Europe.

Clozapine

Effect of atenolol versus ivabradine on heart rate variability in patients of schizophrenia with clozapine-induced tachycardia: a randomized controlled trial.

BACKGROUND: A third of schizophrenia cases are resistant to antipsychotics, where clozapine is the only FDA-approved medication. Clozapine use is often limited by intolerable adverse effects. Persistent tachycardia occurs in approximately 25-54% patients receiving clozapine. Heart rate variability (HRV) is a non-invasive, clinically relevant marker of autonomic nervous system functioning. Atenolol and Ivabradine are usually prescribed for clozapine-induced tachycardia (CIT), although evidence guiding their optimal use remains limited. AIM: This study aimed to compare the effects of atenolol versus ivabradine on HRV in patients with treatment-resistant schizophrenia (TRS) receiving clozapine. METHODS: This open-label randomised clinical trial, conducted at a tertiary-care center over 20 months, involved TRS patients on clozapine for more than three months and having persistent tachycardia. Twenty patients received atenolol 25mg once-daily, while twenty received ivabradine 5mg twice-daily for two months. The primary outcome was the change in the frequency domain of HRV, while the secondary outcomes were time-domains, central and peripheral blood pressure, pulse rate and treatment-emergent adverse events (TEAE). RESULTS: While both drugs significantly reduced pulse-rates (atenolol: -20.56&#xb1;13.00, p<0.001; ivabradine: -21.855&#xb1;12.873, p<0.001). Within-group analysis showed that, the atenolol group had significant improvements in high-frequency [HF] power (p=0.048) and LF/HF ratio (p=0.044), along with a non-significant trend towards increased total power (p=0.053); no significant within-group changes were observed in the ivabradine group. CONCLUSION: No significant between-group differences in HRV parameters were established between atenolol and ivabradine. Ivabradine could be a viable option in patients where atenolol is either contraindicated or not tolerated. Future larger multicentric studies are needed for greater generalisability. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT06505668.

Humans

High-dosage and versatile drug therapy with treatment-resistant psychotic patients.

The author believes that many of the chronic patients in psychiatric institutions and mental health facilities could be helped if physicians were more willing to try different combinations and higher dosages of psychotropic drugs than are commonly used. He presents case studies of two chronic patients who were helped by innovative use of drugs and discusses factors to be considered in implementing high-dosage and versatile drug therapy.

Adolescent

Neurometabolites and Antipsychotic Response in Psychosis: A Mega-Analysis.

IMPORTANCE: Revealing neurobiological markers of antipsychotic nonresponse in psychosis may aid outcome prediction and inform novel treatment targets. OBJECTIVE: To examine differences in neurometabolites in antipsychotic nonresponsive compared to antipsychotic-responsive psychosis using individual participant data and meta-analysis. DATA SOURCES: Web of Science was searched for studies published between January 1, 1980, and November 1, 2025. Authors of 21 eligible studies identified before August 2024 were invited to contribute individual participant data. STUDY SELECTION: Eighteen studies examining neurometabolites by treatment response in psychosis contributed individual participant data for the mega-analysis. These studies plus a further 5 studies were included in the meta-analyses of standardized mean differences and variability. DATA EXTRACTION AND SYNTHESIS: Individual participant data were analyzed using linear mixed models with study as a random effect. Subgroup analyses examined prospective designs and treatment-resistant samples. Published group means and standard deviations were extracted for meta-analyses. MAIN OUTCOMES AND MEASURES: Group differences in glutamate, glutamate plus glutamine, choline, myo-inositol, N-acetylaspartate, &#x3b3;-aminobutyric acid, and glutathione in the medial frontal cortex, dorsolateral prefrontal cortex, thalamus, and basal ganglia. RESULTS: The mega-analysis included 1189 participants from 18 studies; of these, 476 were treatment nonresponders (mean [SD] age, 33.0 [12.5] years; 340 male), 427 were treatment responders (mean [SD] age, 30.3 [11.5] years; 299 male), and 286 were healthy control individuals (mean [SD] age, 31.0 [12.5] years; 170 male). Compared with the antipsychotic response group, nonresponders showed elevations in medial frontal glutamate (Glass &#x394;&#x2009;=&#x2009;0.21; P&#x2009;=&#x2009;.02), glutamate plus glutamine (Glass &#x394;&#x2009;=&#x2009;0.29; P&#x2009;=&#x2009;.002), choline (Glass &#x394;&#x2009;=&#x2009;0.22; P&#x2009;=&#x2009;.03), and myo-inositol (Glass &#x394;&#x2009;=&#x2009;0.35; P&#x2009;=&#x2009;.001); similar elevations were observed relative to control individuals. Elevated medial frontal glutamate plus glutamine in antipsychotic nonresponders compared with responders was also observed prospectively in first-episode psychosis (Glass &#x394;&#x2009;=&#x2009;0.41; P&#x2009;=&#x2009;.002), whereas myo-inositol elevations were greatest in individuals meeting criteria for treatment-resistance (Glass &#x394;&#x2009;=&#x2009;0.64; P&#x2009;=&#x2009;.001). The meta-analysis of 23 studies (1844 participants) also showed elevated medial frontal choline and myo-inositol in antipsychotic nonresponse compared with response. CONCLUSIONS AND RELEVANCE: These findings provide evidence of an association between antipsychotic nonresponse in psychosis with elevations in medial frontal glutamate, choline, and myo-inositol. The presence of elevations in these markers supports the continued investigation of glutamate-acting and inflammatory pathway-associated interventions for psychosis and schizophrenia.

Humans