Danielle Soares Bio

Association of the COMT Met158 allele with trait impulsivity in healthy young adults

Dopamine (DA) is considered to be an important neurotransmitter in the control of impulsive behavior, however, its underlying mechanisms have not been fully elucidated. Catechol-O-methyltransferase (COMT) is a key enzyme in the catabolism of DA within the prefrontal cortex (PFC) and has been suggested to play a role in the mediation of impulsive behavior. The COMT single nucleotide polymorphism (SNP) rs4680 (Val158Met) Met allele has been shown to decrease COMT enzyme activity and is associated with improved PFC cognitive function (intelligence and executive functions). Studies have associated the rs4680 genotype with impulsivity as a symptom in attention deficit hyperactivity disorder and substance abuse. However, only a few studies have assessed the effects of rs4680 on impulsiveness in healthy subjects, the results of which remain controversial. The Barratt Impulsiveness Scale (BIS-11) was applied to 82 healthy volunteers (including 42 females) who were genotyped for COMT rs4680. Subjects carrying the Met/Met genotype scored higher for the BIS-11 second-order factor Non-planning than carriers of the Val/Val genotype. No interaction between gender genotype was detected. Age, gender and education had no effect on the results. The COMT rs4680 Met/Met genotype was associated with higher impulsivity on the BIS-11 second-order factor Non-planning. These results suggest that COMT enzyme activity may be important in the regulation of impulsiveness among young adults. Further studies involving larger samples should be conducted to confirm the results of the present study.

The CACNA1C risk allele selectively impacts on executive function in bipolar type I disorder

Calcium channels are important for converting electrical activity into biochemical events. A single nucleotide polymorphism (SNP) (rs1006737) in the CACNA1C gene has been strongly associated with increased risk for Bipolar disorder (BD) in genome‐wide association studies. Recently, this same SNP has been reported to influence executive function in schizophrenia and controls, but it remains unclear whether this SNP affects behaviour, especially cognition in subjects with BD.

Creativity and executive function across manic, mixed and depressive episodes in bipolar I disorder

INTRODUCTION Creativity is a complex construct involving affective and cognitive components. Bipolar Disorder (BD) has been associated with creativity and is characterized by a wide range of affective and cognitive symptoms. Although studies of creativity in BD have tended to focus on creativity as a trait variable in medicated euthymic patients, it probably fluctuates during symptomatic states of BD. Since creativity is known to involve key affective and cognitive components, it is plausible to speculate that cognitive deficits and symptoms present in symptomatic BD could interfere with creativity. MATERIAL AND METHODS Sixty-seven BD type I patients medication free, age 18-35 years and experiencing a maniac, mixed, or depressive episodes, were assessed for creativity, executive functioning, and intelligence. RESULTS Manic and mixed state patients had higher creativity scores than depressive individuals. Creativity was influenced by executive function measures only in manic patients. Intelligence did not influence creativity for any of the mood episode types. CONCLUSION We propose that creativity in BD might be linked to the putative hyperdopaminergic state of mania and be dependent on intact executive function. Future studies should further explore the role of dopaminergic mechanisms in creativity in BD.

COMT polymorphisms as predictors of cognitive dysfunction during manic and mixed episodes in bipolar I disorder.

Soeiro‐de‐Souza MG, Machado‐Vieira R, Soares Bio D, Do Prado CM, Moreno RA. COMT polymorphisms as predictors of cognitive dysfunction during manic and mixed episodes in bipolar I disorder. Bipolar Disord 2012: 14: 554–564.

Facial emotion recognition and its correlation with executive functions in bipolar I patients and healthy controls.

INTRODUCTION The ability to recognize facial emotions is altered in patients with Bipolar Disorder (BD) during mood episodes and even in euthymia, while cognitive functioning is similarly impaired. This recognition is considered a fundamental skill for successful social interaction. However, it is unclear whether the ability to recognize facial emotions is correlated with the cognitive deficits observed in BD. OBJECTIVE The objective of this study was to evaluate Facial Emotion Recognition (FER) and its correlation with executive function (EF) in BD I patients during mania, depression and euthymia compared to healthy controls. MATERIAL AND METHODS A total of 110 patients with BD I, 18-40 years old were included (41 in manic episode; 31 in depressive episode and 38 euthymic). Patients were assessed for FER and EF (Wisconsin card sorting test - WCST), along with 96 healthy volunteers (18-40 years old) recruited from the University of São Paulo. RESULTS The results showed that BD I patients had lower FER performance compared to controls on fear subtests, happiness, the surprise test, and FER total scores. Moreover, BD I manic patients showed poorer performance for EF compared to controls. Six out of the seven variables of the WCST correlated with FER in both healthy controls and BD euthymic subjects but not in BD patients during mood episodes. CONCLUSION Cognitive deficits and difficulties recognizing facial emotions are present in all mood episodes in BD I patients, even during remission. Although FER is not considered a cognitive domain, these results suggest that, along with EF, it has a complementary function. Hence, further studies should investigate this issue in larger samples and verify whether these similarities also occur at a neurobiological level.

Gender effects of the COMT Val 158 Met genotype on verbal fluency in healthy adults.

Cognitive performance in healthy individuals is associated with gender differences in specific tests; a female advantage has been demonstrated in language tests, whereas a male advantage has been demonstrated in spatial relation examinations. The prefrontal cortex (PFC) mediates important cognitive domains and is influenced by dopamine (DA) activity. The single nucleotide polymorphism (SNP) rs4680 in the catechol‑O‑methyltransferase (COMT) gene results in an amino acid substitution from valine (Val) to methionine (Met). The Met allele has been demonstrated to decrease COMT enzyme activity and improve PFC cognitive function. COMT regulates DA activity in the PFC and exhibits gender effects. The aim of the present study was to investigate the gender‑specific effects of the COMT genotype on cognition in healthy young adults. Seventy‑six healthy subjects were genotyped for COMT rs4680 and submitted to an extensive range of neuropsychological tests assessing aspects of PFC function. The COMT Met allele influenced the performance of executive function. The results revealed gender effects of the COMT rs4680 Met allele on verbal fluency, with positive effects in males and negative effects in females. This suggested that DA activity affects cognitive function in different ways, according to gender.

LICAVAL: combination therapy in acute and maintenance treatment of bipolar disorder

BackgroundThe challenge of Bipolar Disorder (BD) treatment is due to the complexity of the disease. Current guidelines represent an effort to help clinicians in their everyday practice but still have limitations, specially concerning to long term treatment. LICAVAL (efficacy and tolerability of the combination ofLIthium andCArbamazepine compared to lithium andVALproic acid in the treatment of young bipolar patients) study aim to evaluate acute and maintenance phase of BD treatment with two combined drugs.MethodsLICAVAL is a single site, parallel group, randomized, outcome assessor blinded trial. BD I patients according to the DSM-IV-TR, in depressive, manic,/hypomanic or mixed episode, aged 18 to 35 years are eligible. After the diagnostic assessments, the patients are allocated for one of the groups of treatment (lithium + valproic acid or lithium + carbamazepine). Patients will be followed up for 8 weeks in phase I (acute treatment), 6 months in phase II (continuation treatment) and 12 months in phase III (maintenance treatment). Outcome assessors are blind to the treatment. The main outcome is the evaluation of changes in mean scores on CGI-BP-M between baseline and endpoint at the end of each phase of the study.ResultsLICAVAL is currently in progress, with patients in phase I, II or III. It will extended until august 2012.ConclusionsTrials comparing specific treatments efficacy in BD (head to head) can show relevant information in clinical practice. Long term treatment is an issue of great important and should be evaluated carefully in more studies as long as BD is a chronic disease.Trial registrationClinicalTrials.gov Identifier: NCT00976794

Apolipoprotein E genotype and Cognition in Bipolar Disorder

Apolipoprotein E (APOE) has been extensively studied as a risk factor for sporadic and late onset Alzheimers Disease (AD). APOE allele*3, the most frequent variant, is not associated to cognitive dysfunction (CD) or to increased AD risk. Differently, the *4 allele is a well‐established risk factor for CD, while the *2 allele is associated with survival and longevity. CD is an important feature of Bipolar Disorder (BD) and recent data suggest that CD may be one of its endophenotypes, although controversial results exist. The aim of this research is to study the association of APOE genotype (APOE) and neurocognitive function in a sample of drug free young BD‐type I patients. Sample consisted of 25 symptomatic BD (type I) patients (age 18–35 years old). They were submitted to an extensive neuropsychological evaluation and genotyped for APOE. Subjects with allele*2 presented better cognitive performance. The presence of allele*4 was associated with worse performance in a few executive tasks. APOE*3*3 was associated with overall severe dysfunction on cognitive performance. In young individuals with nontreated BD‐type I, APOE may predict cognitive performance. Further and larger studies on APOE and cognition in BD are required to clarify whether APOE is a BD cognitive endophenotype.

The impact of limbic system morphology on facial emotion recognition in bipolar I disorder and healthy controls

Introduction Impairments in facial emotion recognition (FER) have been reported in bipolar disorder (BD) subjects during all mood states. This study aims to investigate the impact of limbic system morphology on FER scores in BD subjects and healthy controls. Material and methods Thirty-nine euthymic BD I (type I) subjects and 40 healthy controls were subjected to a battery of FER tests and examined with 3D structural imaging of the amygdala and hippocampus. Results The volume of these structures demonstrated a differential pattern of influence on FER scores in BD subjects and controls. In our control sample, larger left and right amygdala demonstrated to be associated to less recognition of sadness faces. In BD group, there was no impact of amygdala volume on FER but we observed a negative impact of the left hippocampus volume in the recognition of happiness while the right hippocampus volume positively impacted on the scores of happiness. Conclusion Our results indicate that amygdala and hippocampus volumes have distinct effects on FER in BD subjects compared to controls. Knowledge of the neurobiological basis of the illness may help to provide further insights on the role of treatments and psychosocial interventions for BD. Further studies should explore how these effects of amygdala and hippocampus volumes on FER are associated with social networks and social network functioning.

Epistasis between COMT Val158Met and DRD3 Ser9Gly polymorphisms and cognitive function in schizophrenia: genetic influence on dopamine transmission.

OBJECTIVE To assess the relationship between cognitive function, a proposed schizophrenia endophenotype, and two genetic polymorphisms related to dopamine function, catechol-O-methyl transferase (COMT) Val158Met and dopamine receptor 3 (DRD3) Ser9Gly. METHODS Fifty-eight outpatients with schizophrenia/schizoaffective disorder and 88 healthy controls underwent neurocognitive testing and genotyping. Analyses of covariance (ANCOVAs) using age, sex, and years of education as covariates compared cognitive performance for the proposed genotypes in patients and controls. ANCOVAs also tested for the epistatic effect of COMT and DRD3 genotype combinations on cognitive performance. RESULTS For executive functioning, COMT Val/Val patients performed in a similar range as controls (30.70-33.26 vs. 35.53-35.67), but as COMT Met allele frequency increased, executive functioning worsened. COMT Met/Met patients carrying the DRD3 Ser/Ser genotype performed poorest (16.184 vs. 27.388-31.824). Scores of carriers of this COMT/DRD3 combination significantly differed from all DRD3 Gly/Gly combinations (p < 0.05), from COMT Val/Met DRD3 Ser/Gly (p = 0.02), and from COMT Val/Val DRD3 Ser/Ser (p = 0.01) in patients. It also differed significantly from all control scores (p < 0.001). CONCLUSION Combined genetic polymorphisms related to dopamine neurotransmission might influence executive function in schizophrenia. Looking at the effects of multiple genes on a single disease trait (epistasis) provides a comprehensive and more reliable way to determine genetic effects on endophenotypes.