Predictors of clozapine discontinuation at 2 years in treatment-resistant schizophrenia

Comparison of the Effectiveness and Safety of Clozapine Between Once-Daily and Divided Dosing Regimen in Patients With Treatment-Resistant Schizophrenia

BACKGROUND

Clozapine is the most effective antipsychotic with respect to the incidence of discontinuation and is indicated for treatment-resistant schizophrenia. Although the recommendation for clozapine administration is divided dosing, once-daily dosing of clozapine is commonly prescribed in many countries. However, there is currently no clinical data comparing all-cause discontinuation between the 2 methods of administration of clozapine.

OBJECTIVES

To compare the all-cause discontinuation and safety of clozapine administration between once-daily and divided dosing regimens.

METHODS

This was a retrospective cohort study. Participants were patients with treatment-resistant schizophrenia who had received 300 to 600 mg/day of clozapine for at least 3 months. Data were collected from outpatient medical records at Somdet Chaopraya Institute of Psychiatry. Eligible patients were classified into 2 groups: once-daily dosing and divided dosing. The primary outcome was the all-cause discontinuation rate between groups. The duration of the study was 2 years.

RESULTS

One hundred eighteen patients were included and analyzed in this study (once-daily dosing group: n = 58; divided dosing group: n = 60). There was no significant difference in all-cause discontinuation between the 2 groups (odds ratio 1.03; 95% confidence interval: [0.28, 3.79]: P = 1.00), or adverse events between groups.

CONCLUSION AND RELEVANCE

In patients with treatment-resistant schizophrenia, there were no significant differences in effectiveness or safety between once-daily and divided dosing of clozapine. Further prospective studies with larger sample sizes are required to confirm these findings.

Side effects of clozapine in older adults with treatment-resistant schizophrenia compared to younger adults

OBJECTIVES

To study the differences in side effects of clozapine between older adults aged ≥55 years and younger adults aged 18-55 years with treatment-resistant schizophrenia.

METHODS

A retrospective cohort study in a large mental health institute in the Netherlands. All patients diagnosed with treatment-resistant schizophrenia who started with clozapine between 2011 and 2020 (N = 284) were included. We compared the number and type of side effects reported in the electronic patient files as well as the number of treatment discontinuations and the time until discontinuation, both due to side effects, of older adults versus younger adults.

RESULTS

In the younger age group (N = 183), the number of reported side effects was significantly higher in the first 3 months of treatment (Mann-Whitney U = 7341.5, p = 0.004) and after those 3 months (Mann-Whitney U = 5668.5, p < 0.001) compared with the number reported in the older age group (N = 101). Sedation, hypersalivation, dizziness, tachycardia, heartburn, nausea, weight gain, and constipation were reported significantly more often in the younger age group, and only extrapyramidal symptoms were reported significantly more often in the older age group. There was no significant difference in the number of treatment discontinuations due to side effects (23% vs. 21.8%, Chi-2 = 0.051, df = 1, p = 0.821) and time until discontinuation due to side effects (b = 0.091, SE = 0.335, p = 0.798) between younger and older adults.

CONCLUSIONS

Side effects of clozapine were reported significantly less often in older patients compared with younger patients. Older patients did not discontinue treatment due to side effects more often or earlier than younger patients. Older patients with schizophrenia may not be more vulnerable to side effects than younger adults.

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.

Changes in neurotransmitter levels, brain structural characteristics, and their correlation with PANSS scores in patients with first-episode schizophrenia

BACKGROUND

In patients with schizophrenia, the brain structure and neurotransmitter levels change, which may be related to the occurrence and progression of this disease.

AIM

To explore the relationships between changes in neurotransmitters, brain structural characteristics, and the scores of the Positive and Negative Symptom Scale (PANSS) in patients with first-episode schizophrenia.

METHODS

The case group comprised 97 patients with schizophrenia, who were evaluated using the Canadian Neurological Scale and confirmed by laboratory tests at Ningbo Mental Hospital from January 2020 to July 2022. The control group comprised 100 healthy participants. For all participants, brain structural characteristics were explored by measuring brain dopamine (DA), glutamic acid (Glu), and gamma-aminobutyric acid (GABA) levels, with magnetic resonance imaging. The case group was divided into negative and positive symptom subgroups using PANSS scores for hierarchical analysis. Linear correlation analysis was used to analyze the correlations between neurotransmitters, brain structural characteristics, and PANSS scores.

RESULTS

Patients in the case group had higher levels of DA and lower levels of Glu and GABA, greater vertical and horizontal distances between the corpus callosum and the inferior part of the fornix and larger ventricle area than patients in the control group (P < 0.05). Patients with positive schizophrenia symptoms had significantly higher levels of DA, Glu, and GABA than those with negative symptoms (P < 0.05). In patients with positive schizophrenia symptoms, PANSS score was significantly positively correlated with DA, vertical and horizontal distances between the corpus callosum and the infrafornix, and ventricular area, and was significantly negatively correlated with Glu and GABA (P < 0.05). In patients with negative schizophrenia symptoms, PANSS score was significantly positively correlated with DA, vertical distance between the corpus callosum and the infrafornix, horizontal distance between the corpus callosum and the infrafornix, and ventricular area, and was significantly negatively correlated with Glu and GABA (P < 0.05).

CONCLUSION

In patients with first-episode schizophrenia, DA levels increased, Glu and GABA levels decreased, the thickness of the corpus callosum increased, and these variables were correlated with PANSS scores.

Changes in neurotransmitter levels, brain structural characteristics, and their correlation with PANSS scores in patients with first-episode schizophrenia

BACKGROUND

In patients with schizophrenia, the brain structure and neurotransmitter levels change, which may be related to the occurrence and progression of this disease.

AIM

To explore the relationships between changes in neurotransmitters, brain structural characteristics, and the scores of the Positive and Negative Symptom Scale (PANSS) in patients with first-episode schizophrenia.

METHODS

The case group comprised 97 patients with schizophrenia, who were evaluated using the Canadian Neurological Scale and confirmed by laboratory tests at Ningbo Mental Hospital from January 2020 to July 2022. The control group comprised 100 healthy participants. For all participants, brain structural characteristics were explored by measuring brain dopamine (DA), glutamic acid (Glu), and gamma-aminobutyric acid (GABA) levels, with magnetic resonance imaging. The case group was divided into negative and positive symptom subgroups using PANSS scores for hierarchical analysis. Linear correlation analysis was used to analyze the correlations between neurotransmitters, brain structural characteristics, and PANSS scores.

RESULTS

Patients in the case group had higher levels of DA and lower levels of Glu and GABA, greater vertical and horizontal distances between the corpus callosum and the inferior part of the fornix and larger ventricle area than patients in the control group (P < 0.05). Patients with positive schizophrenia symptoms had significantly higher levels of DA, Glu, and GABA than those with negative symptoms (P < 0.05). In patients with positive schizophrenia symptoms, PANSS score was significantly positively correlated with DA, vertical and horizontal distances between the corpus callosum and the infrafornix, and ventricular area, and was significantly negatively correlated with Glu and GABA (P < 0.05). In patients with negative schizophrenia symptoms, PANSS score was significantly positively correlated with DA, vertical distance between the corpus callosum and the infrafornix, horizontal distance between the corpus callosum and the infrafornix, and ventricular area, and was significantly negatively correlated with Glu and GABA (P < 0.05).

CONCLUSION

In patients with first-episode schizophrenia, DA levels increased, Glu and GABA levels decreased, the thickness of the corpus callosum increased, and these variables were correlated with PANSS scores.