Changing the Antipsychotic in Early Nonimprovers to Amisulpride or Olanzapine: Randomized, Double-Blind Trial in Patients With Schizophrenia

BACKGROUND AND HYPOTHESIS

Meta-analyses have shown that the majority of patients with schizophrenia who have not improved after 2 weeks of treatment with an antipsychotic drug are unlikely to fully respond later. We hypothesized that switching to another antipsychotic with a different receptor binding profile is an effective strategy in such a situation.

STUDY DESIGN

In total, 327 inpatients with an acute exacerbation of schizophrenia were randomized to double-blind treatment with either olanzapine (5-20 mg/day) or amisulpride (200-800 mg/day). Those patients who had not reached at least 25% Positive-and-Negative-Syndrome-Scale (PANSS) total score reduction from baseline after 2 weeks (the "non-improvers") were rerandomized double-blind to either staying on the same compound ("stayers") or to switching to the other antipsychotic ("switchers") for another 6 weeks. The primary outcome was the difference in the number of patients in symptomatic remission between the combined "switchers" and the "stayers" after 8 weeks of treatment, analyzed by logistic regression.

STUDY RESULTS

A total of 142 nonimprovers were rerandomized at week two. 25 (45.5 %) of the 'stayers' compared to 41 (68.3 %) of the "switchers" reached remission at endpoint (p = .006). Differences in secondary efficacy outcomes were not significant, except for the PANSS negative subscore and the Clinical-Global-Impression-Scale. "Switchers" and "stayers" did not differ in safety outcomes.

CONCLUSIONS

Switching "non-improvers" from amisulpride to olanzapine or vice-versa increased remission rates and was safe. The superiority in the primary outcome was, however, not paralleled by significant differences in most secondary efficacy outcomes and the effect was only apparent at the last visit making replications of longer duration necessary.

Increasing sample diversity in psychiatric genetics - Introducing a new cohort of patients with schizophrenia and controls from Vietnam - Results from a pilot study

OBJECTIVES

Genome-Wide Association Studies (GWAS) of Schizophrenia (SCZ) have provided new biological insights; however, most cohorts are of European ancestry. As a result, derived polygenic risk scores (PRS) show decreased predictive power when applied to populations of different ancestries. We aimed to assess the feasibility of a large-scale data collection in Hanoi, Vietnam, contribute to international efforts to diversify ancestry in SCZ genetic research and examine the transferability of SCZ-PRS to individuals of Vietnamese Kinh ancestry.

METHODS

In a pilot study, 368 individuals (including 190 SCZ cases) were recruited at the Hanoi Medical University's associated psychiatric hospitals and outpatient facilities. Data collection included sociodemographic data, baseline clinical data, clinical interviews assessing symptom severity and genome-wide SNP genotyping. SCZ-PRS were generated using different training data sets: (i) European, (ii) East-Asian and (iii) trans-ancestry GWAS summary statistics from the latest SCZ GWAS meta-analysis.

RESULTS

SCZ-PRS significantly predicted case status in Vietnamese individuals using mixed-ancestry (R² liability = 4.9%, p = 6.83 × 10^-8), East-Asian (R² liability = 4.5%, p = 2.73 × 10^-7) and European (R² liability = 3.8%, p = 1.79 × 10^-6) discovery samples.

DISCUSSION

Our results corroborate previous findings of reduced PRS predictive power across populations, highlighting the importance of ancestral diversity in GWA studies.

COMT Val 158 Met polymorphism is associated with cognitive flexibility in a signal discrimination task in schizophrenia

BACKGROUND

Associations between the well-known functional single nucleotide polymorphism Val (158)Met in the gene encoding catechol- O-methyltransferase (COMT) and cognitive do-mains affected in schizophrenia are inconsistent regarding directionality and specific impact and call for a more fundamental cognitive endophenotype. Recent studies suggest that the COMT genotype contributes to cognitive flexibility, a fundamental cognitive ability that potentially influences an individual's performance in a variety of other neurocognitive tasks.

METHODS

We investigated the association between COMT Val (158)Met genotype and cognitive flexibility as assessed by signal discrimination in the Continuous Performance Test - Identical Pairs version in a cohort of 111 German schizophrenic patients.

RESULTS

COMT genotype was significantly associated with signal discrimination index d' in schizophrenia. The Val/Val genotype was associated with the highest and the Met/Met genotype with the lowest scores; heterozygous individuals displayed an intermediate performance.

CONCLUSIONS

Our data suggest that allelic variation at the COMT Val (158)Met locus may influence signal discrimination capacity in schizophrenia and confirm that Val loading, probably due to decreased prefrontal dopamine availability, is associated with greater cognitive flexibility, which in turn may influence other cognitive measures that have been associated with COMT to date.