Influence of the catechol-O-methyltransferase Val108/158Met polymorphism on the plasma concentration of catecholamine metabolites and on clinical features in type I bipolar disorder--a preliminary report

Lifetime and point prevalence of psychotic symptoms in adults with bipolar disorders: a systematic review and meta-analysis

Psychotic symptoms, that we defined as delusions or hallucinations, are common in bipolar disorders (BD). This systematic review and meta-analysis aims to synthesise the literature on both lifetime and point prevalence rates of psychotic symptoms across different BD subtypes, including both BD type I (BDI) and BD type II (BDII). We performed a systematic search of Medline, PsycINFO, Embase and Cochrane Library until 5 August 2021. Fifty-four studies (N = 23 461) of adults with BD met the predefined inclusion criteria for evaluating lifetime prevalence, and 24 studies (N = 6480) for evaluating point prevalence. Quality assessment and assessment of publication bias were performed. Prevalence rates were calculated using random effects meta-analysis, here expressed as percentages with a 95% confidence interval (CI). In studies of at least moderate quality, the pooled lifetime prevalence of psychotic symptoms in BDI was 63% (95% CI 57.5-68) and 22% (95% CI 14-33) in BDII. For BDI inpatients, the pooled lifetime prevalence was 71% (95% CI 61-79). There were no studies of community samples or inpatient BDII. The pooled point prevalence of psychotic symptoms in BDI was 54% (95 CI 41-67). The point prevalence was 57% (95% CI 47-66) in manic episodes and 13% (95% CI 7-23.5) in depressive episodes. There were not enough studies in BDII, BDI depression, mixed episodes and outpatient BDI. The pooled prevalence of psychotic symptoms in BDI may be higher than previously reported. More studies are needed for depressive and mixed episodes and community samples.Prospero registration number: CRD 42017052706.

Twenty years of Lithium pharmacogenetics: A systematic review

Lithium is among the best proven treatments for patients diagnosed with Bipolar Disorder, however response to Lithium appears to be considerably variable among individuals and it has been suggested that this inconstancy in Lithium response could be genetically determined. Starting from this perspective, in the last few decades, a number of pharmacogenetic studies have attempted to identify genetic variants, which might be associated with response to Lithium in bipolar patients, in order to develop a pharmacogenetics test to tailor treatment on patients, identifying who will benefit the most from therapy with Lithium. Within this context, authors have critically reviewed pharmacogenetic studies of Lithium response in bipolar disorder, suggesting strategies for future work in this field. Computerized searches of PubMed and Embase databases, for studies published between 1998 and January 2018, was performed: 1162 studies were identified but only 37 relevant papers were selected for detailed review. Despite some interesting preliminary findings, the pharmacogenetics of Lithium and the development of a specific pharmacogenetics test in bipolar disorder appears to be a field still in its infancy, even though the advent of genome-wide association studies holds particular promise for future studies, which should include larger samples.

COMT Val 108/158 Met polymorphism and treatment response to aripiprazole in patients with acute schizophrenia

INTRODUCTION

The COMT Val 108/158 Met polymorphism (rs4680) may affect treatment response to antipsychotics, as well as metabolism and dynamics of neurotransmitters during the treatment of schizophrenia. We investigated the effects of the COMT Val 108/158 Met polymorphism on treatment response to aripiprazole and plasma monoamine metabolite levels in patients with acute schizophrenia.

MATERIALS AND METHODS

Forty patients with schizophrenia were treated with aripiprazole for 6 weeks. We measured Positive and Negative Syndrome Scale (PANSS) and plasma levels of homovanillic acid (HVA) and plasma MHPG (3-methoxy-4-hydroxyphenethyleneglycol) at baseline and endpoint. The COMT Val 108/158 Met polymorphism was genotyped with the polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

There were significant genotype-time interactions on PANSS total and general psychopathology scores, with Met/Met genotype showing greater improvement. The response rate to aripiprazole did not differ between COMT Val 108/158 Met genotype groups. We found a significant time effect on plasma MHPG levels, but no time effect on plasma HVA levels or time-genotype interactions in the plasma levels of HVA and MHPG. Although the responder rate did not differ among the 3 genotype groups.

CONCLUSION

Our results suggest that individuals with the Met/Met genotype had greater improvement in PANSS score after the treatment with aripiprazole. On the other hand, the Val 108/158 Met polymorphism may not induce changes in plasma levels of monoamine metabolites during aripiprazole treatment. Because of the small sample size, further studies are needed to confirm and to extend our results.

COMT haplotypes, catecholamine metabolites in plasma and clinical response in schizophrenic and bipolar patients

Aim: We examined the association of COMT haplotypes and plasma metabolites of catecholamines in relation to the clinical response to antipsychotics in schizophrenic and bipolar patients. Patients & methods: We studied 165 patients before and after four weeks of treatment, and 163 healthy controls. We assessed four COMT haplotypes and the plasma concentrations of HVA, DOPAC and MHPG. Results: Bipolar patients: haplotypes are associated with age at onset and clinical evolution. In schizophrenic patients, an haplotype previously associated with increased risk, is related to better response of negative symptoms. Conclusion: Haplotypes would be good indicators of the clinical status and the treatment response in bipolar and schizophrenic patients. Larger studies are required to elucidate the clinical usefulness of these findings.

Biological aspects and candidate biomarkers for psychotic bipolar disorder: A systematic review

AIM

We carried out a systematic review of the available literature about potential biomarkers of psychotic bipolar disorder (BD-P), a specific subset presenting worse outcome and greater risk of relapse than non-psychotic bipolar disorder (BD-NP).

METHODS

We searched the main psychiatric databases (PubMed, ISI Web of Knowledge, PsychInfo). Only original articles with the main topic of BD-P compared to schizophrenia/BD-NP/healthy controls (HC) written in English from 1994 to 2015 were included.

RESULTS

BD-P patients presented higher kynurenic acid levels in the cerebrospinal fluid, elevated anti- S accharomyces cerevisiae antibodies levels, and lower serum levels of dehydroepiandrosterone sulfate and progesterone than BD-NP/HC. Event-related potentials abnormalities have been identified in BD-P with respect to BD-NP. BD-P patients also presented bigger ventricles but similar hippocampal volumes compared to BD-NP/HC. Although the results are contrasting, some cognitive deficits seemed to be related to the psychotic dimension of bipolar affective disorder, such as impairment in verbal/logical memory, working memory, verbal and semantic fluency and executive functioning. Finally, polymorphisms of genes, such as NRG1, 5HTTLPR (s), COMT, DAOA and some chromosome regions (16p12 and 13q), were positively associated with BD-P.

CONCLUSION

Data about the identification of specific biomarkers for BD-P are promising, but most of them have not yet been replicated. They could lead the clinicians to an early diagnosis and proper treatment, thus ameliorating outcome of BD-P and reducing the biological changes associated with a long duration of illness. Further studies with bigger samples are needed to detect more specific biological markers of the psychotic dimension of bipolar affective disorder.

Pharmacogenomics of bipolar disorder

Bipolar disorder (BD) is a lifelong severe psychiatric condition with high morbidity, disability and excess mortality. The longitudinal clinical trajectory of BD is significantly modified by pharmacological treatment(s), both in acute and in long-term stages. However, a large proportion of BD patients have inadequate response to pharmacological treatments. Pharmacogenomic research may lead to the identification of molecular predictors of treatment response. When integrated with clinical information, pharmacogenomic findings may be used in the future to determine the probability of response/nonresponse to treatment on an individual basis. Here we present a selective review of pharmacogenomic findings in BD. In light of the evidence suggesting a genetic effect of lithium reponse in BD, we focused particularly on the pharmacogenomic literature relevant to this trait. The article contributes a detailed overview of the current status of pharmacogenomics in BD and offers a perspective on the challenges that can hinder its transition to personalized healthcare.

Recurrence of bipolar mania is associated with catechol-O-methyltransferase Val(108/158)Met polymorphism

BACKGROUND

Catechol-O-methyltransferase (COMT) inactivates catecholamines, and a G-A transition in the COMT gene (rs4680) influences the enzyme activity and the interaction between cortical and subcortical dopaminergic neurotransmission. In patients affected by bipolar disorder rs4680 can influence antidepressant response and the propensity to develop psychotic symptoms, with the Met/Met genotype exerting a protective role. The same genotype could influence other dopamine-associated psychopathological features, such as mania.

METHODS

We genotyped rs4680 in a sample of 163 patients affected by bipolar disorder type I, and assessed the personal history of recurrence of the illness.

RESULTS

We observed a significant association between homozygosis for the rs4680 COMT low-activity variant and a reduced recurrence of manic, but not depressive, episodes during the course of the illness.

CONCLUSIONS

We suggest that rs4680 could be an inheritable aspect of the mechanisms of dopamine regulation that influence the individual susceptibility of patients with bipolar disorder to develop manic episodes of illness.

Association between catechol-O-methyltransferase Val(108/158)Met polymorphism and psychotic features of bipolar disorder

BACKGROUND

Catechol-O-methyltransferase (COMT) inactivates catecholamines, and a G-A transition in the COMT gene (rs4680) influences the enzyme activity and the interaction between cortical and subcortical dopaminergic neurotransmission. Studies in healthy participants and in patients affected by schizophrenia suggested that rs4680 can influence the propensity to develop psychotic symptoms, with the Met low-activity allele exerting a protective role. Previous studies in bipolar patients reported non-significant trends in the same direction.

METHODS

We genotyped rs4680 in a sample of 467 patients affected by bipolar disorder type I with or without a previous illness episode with psychotic features (DSM-IV criteria: delusions or hallucinations).

RESULTS

We observed a significant association between homozygosis for the rs4680 COMT low-activity variant and a reduced risk of experiencing illness episodes with psychotic features during the course of the illness. The Met/Met genotype was more common among patients without psychotic features, and while in the non-psychotic group the Val/Val genotype had a distribution similar to Met/Met, in the group of patients who experienced episodes with psychotic symptoms the proportion of Val/Val homozygotes was the double of Met/Met.

CONCLUSIONS

We suggest that rs4680 could be an inheritable aspect of the mechanisms of dopamine regulation that could influence the individual susceptibility of patients with bipolar disorder to develop psychotic symptoms.

Pharmacogenomics of mood stabilizers in the treatment of bipolar disorder

Bipolar disorder (BD) is a chronic and often severe psychiatric illness characterized by manic and depressive episodes. Among the most effective treatments, mood stabilizers represent the keystone in acute mania, depression, and maintenance treatment of BD. However, treatment response is a highly heterogeneous trait, thus emphasizing the need for a structured informational framework of phenotypic and genetic predictors. In this paper, we present the current state of pharmacogenomic research on long-term treatment in BD, specifically focusing on mood stabilizers. While the results provided so far support the key role of genetic factors in modulating the response phenotype, strong evidence for genetic predictors is still lacking. In order to facilitate implementation of pharmacogenomics into clinical settings (i.e., the creation of personalized therapy), further research efforts are needed.

Catechol-O-methyltransferase Val158Met polymorphism affects therapeutic response to mood stabilizer in symptomatic manic patients

Catechol-O-methyltransferase (COMT) is a candidate gene for the pathogenesis of some psychiatric disorders. The aim of this study is to examine the role of the COMT gene Val158Met polymorphism on the clinical aspects of bipolar disorder including symptomatology and therapeutic response. This study comprised 144 unrelated manic patients who met strict DSM-IV criteria for bipolar I disorder and 157 healthy unrelated controls. All subjects were of Korean ethnicity. To evaluate the clinical symptoms, we used the Young Mania Rating Scale at baseline and 6 weeks after treatment. No statistically significant difference in genotype distribution was found between manic patients and normal controls. There was also no significant difference in symptomatology among the genotypes in manic patients. In therapeutic response, however, patients with the Met/Met genotype were significantly more frequent in the non-responder than in the responder group. Our results suggest that the COMT gene polymorphism in the therapeutic response to mood stabilizers in manic patients. Further studies with a larger number of subjects and well-controlled design will be required to better understand the role of the COMT gene polymorphism on the therapeutic response to mood stabilizer in manic patients.

The role of dopamine in bipolar disorder

OBJECTIVE

Despite effective pharmacological treatments for bipolar disorder, we still lack a comprehensive pathophysiological model of the illness. Recent neurobiological research has implicated a number of key brain regions and neuronal components in the behavioural and cognitive manifestations of bipolar disorder. Dopamine has previously been investigated in some depth in bipolar disorder, but of late has not been a primary focus of attention. This article examines the role of dopamine in bipolar disorder, incorporating recent advances into established models where possible.

METHODS

A critical evaluation of the literature was undertaken, including a review of behavioural, neurochemical, receptor, and imaging studies, as well as genetic studies focusing on dopamine receptors and related metabolic pathways. In addition, pharmacologic manipulation of the central dopaminergic pathways and comparisons with other disease states such as schizophrenia were considered, principally as a means of exploring the hypothesised models.

RESULTS

Multiple lines of evidence, including data from pharmacological interventions and structural and functional magnetic resonance imaging studies, suggest that the dopaminergic system may play a central role in bipolar disorder.

CONCLUSION

Future research into the pathophysiological mechanisms of bipolar disorder and the development of new treatments for bipolar disorder should focus on the dopaminergic system.