Stella Giakoumaki

• MSc, PhD
• Professor at University of Crete

Objective: The present study aimed to examine facial emotion recognition in a sample from the general population with elevated schizotypal traits, as defined by the four-factor model of schizotypy, and the association of facial emotion recognition and the schizotypal dimensions with psychological well-being. Method: Two hundred and thirty-eight...

Objective To examine cold (based on logical reasoning) versus hot (having emotional components) executive function processes in groups with high individual schizotypal traits. Method Two-hundred and forty-seven participants were administered the Schizotypal Personality Questionnaire and were allocated into schizotypal (cognitive-perceptual, parano...

Ample research findings indicate that there is altered brain functioning in the schizophrenia spectrum. Nevertheless, functional neuroimaging findings remain ambiguous for healthy individuals expressing high schizotypal traits and patients with schizotypal personality disorder (SPD). The purpose of this systematic review was to identify patterns of...

The findings on the association of schizotypal traits with the perception of visual illusions are scarce and inconsistent and have not taken into consideration potential effects of childhood traumatic experiences, a risk factor for schizophrenia‐spectrum conditions. Thus, the present study addressed the question of potential moderating effects of e...

Aim: Previous research has indicated that individuals expressing high schizotypal traits and patients with Schizotypal Personality Disorder (SPD), show deficits in facial emotion recognition, compared to low schizotypal or control groups. On the other hand, non-significant findings also exist and the association of facial emotion recognition defic...

The near and far transfer effects of Working Memory (WM) training have yielded discrepant findings while there is no literature on the effects of Executive Working Memory (EWM) training. The present study aimed to investigate the far transfer effects of EWM on cognitive flexibility. Community participants (n = 144) were allocated into a fully-, a p...

Broad-based cognitive deficits are an enduring and disabling symptom for many patients with severe mental illness, and these impairments are inadequately addressed by current medications. While novel drug targets for schizophrenia and depression have emerged from recent large-scale genome-wide association studies (GWAS) of these psychiatric disorde...

Although there is ample evidence from cross-sectional studies indicating cognitive deficits in high schizotypal individuals that resemble the cognitive profile of schizophrenia-spectrum patients, there is still lack of evidence by longitudinal/follow-up studies. The present study included assessments of schizotypal traits and a wide range of cognit...

A critical link between schizotypy and schizophrenia is impoverished cognitive functioning. In the majority of studies, though: (1) cognition is examined with standard neuropsychological tasks; and (2) high‐schizotypal individuals are defined according to criteria applied in the respective study sample. Taking these considerations into account, the...

Cloninger’s biopsychological model for personality distinguishes between Temperament [Novelty Seeking, Harm Avoidance (HA), Reward Dependence (RD), Persistence (PS)], and Character [Self-Directedness (SD), Cooperativeness (CO), Self-Transcendence (ST)] traits. Cloninger has also described three sets of complex interactions among these traits, which...

Working memory refers to a cognitive function that provides temporary storage and manipulation of the information necessary for complex cognitive tasks. Due to its central role in general cognition, several studies have investigated the possibility that training on working memory tasks could improve not only working memory function but also increas...

Introduction: According to the fully-dimensional approach, schizotypy is a personality trait present in the population in a continuous manner while the quasi-dimensional approach emphasises its extreme presentations. In this study we examined the relationship between sensorimotor gating, a core risk-index of the schizophrenia-spectrum, and four sch...

Background Cognitive traits demonstrate significant genetic correlations with many psychiatric disorders and other health-related traits. Many neuropsychiatric and neurodegenerative disorders are marked by cognitive deficits. Therefore, genome-wide association studies (GWAS) of general cognitive ability might suggest potential targets for nootropic...

The efficacy of working memory training (WMT) has been a controversial and debated issue during the past years. Despite a large number of training studies and several meta-analyses, the matter has not yet been solved. So the aim of this research is the investigation of the effect of the working memory training (WMT) on cognitive flexibility in both...

Susceptibility to schizophrenia is inversely correlated with general cognitive ability at both the phenotypic and the genetic level. Paradoxically, a modest but consistent positive genetic correlation has been reported between schizophrenia and educational attainment, despite the strong positive genetic correlation between cognitive ability and edu...

General cognitive function is a prominent and relatively stable human trait that is associated with many important life outcomes. We combine cognitive and genetic data from the CHARGE and COGENT consortia, and UK Biobank (total N = 300,486; age 16–102) and find 148 genome-wide significant independent loci (P < 5 × 10−8) associated with general cogn...

Studies comparing cognitive processes between familial and sporadic schizophrenia have yielded inconsistent findings. In this study we examined differences in neurocognition and schizotypal traits in unaffected relatives of schizophrenia-spectrum patients with either the familial (multiplex) or the sporadic (simplex) subtype of the disorder, taking...

Liability to schizophrenia is inversely correlated with general cognitive ability at both the phenotypic and genetic level. Paradoxically, a modest but consistent positive genetic correlation has been reported between schizophrenia and educational attainment, despite the strong positive genetic correlation between cognitive ability and educational...

Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84–88) presented a critique of our recently published paper in Cell Reports entitled ‘Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets’ (Lam et al., Cell Reports , Vol. 21, 2017, 2597–2613). Specifically, Hill offered severa...

The efficacy of working memory training (WMT) has been a controversial and debated issue during the past years. Despite a large number of training studies and several meta-analyses, the matter has not yet been solved. However, at the same time similar efforts concerning executive functions are less popular. These efforts suggest that systematic tra...

Intelligence is highly heritable 1 and a major determinant of human health and well-being 2 . Recent genome-wide meta-analyses have identified 24 genomic loci linked to variation in intelligence3-7, but much about its genetic underpinnings remains to be discovered. Here, we present a large-scale genetic association study of intelligence (n = 269,86...

General cognitive function is a prominent and relatively stable human trait that is associated with many important life outcomes. We combine cognitive and genetic data from the CHARGE and COGENT consortia, and UK Biobank (total N = 300,486; age 16-102) and find 148 genome-wide significant independent loci (P < 5 × 10-8) associated with general cogn...

Elucidating schizotypal traits is important if we are to understand the various manifestations of psychosis spectrum liability and to reliably identify individuals at high risk for psychosis. The present study examined the network structures of (1) 9 schizotypal personality domains and (2) 74 individual schizotypal items, and (3) explored whether n...

Background: Schizotypal traits are expressions of underlying vulnerability to psychotic disorders which have a potential impact on mental health status, neurocognition, quality of life, and daily functioning. To date, little research has examined epidemiologic landscape of schizotypal traits at the cross-national level. Our aim was to study the ex...

Hill (2017) presented a critique of our recently published paper in Cell Reports entitled “Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets” (Lam et al. 2017). Specifically, Hill offered several inter-related comments suggesting potential problems with our use of a new analytic...

Sensorimotor gating measured by prepulse inhibition (PPI) of the acoustic startle response (ASR) has been proposed as one of the most promising electrophysiological endophenotypes of schizophrenia. During the past decade, a number of publications have reported significant associations between genetic polymorphisms and PPI in samples of schizophreni...

The Schizotypal Personality Questionnaire-Brief (SPQ-B) was developed with the aim of examining variations in healthy trait schizotypy, as well as latent vulnerability to psychotic-spectrum disorders. No previous study has studied the cross-cultural validity of the SPQ-B in a large cross-national sample. The main goal of the present study was to an...

Molecular Psychiatry publishes work aimed at elucidating biological mechanisms underlying psychiatric disorders and their treatment

General cognitive function is a prominent human trait associated with many important life outcomes 1,2 , including longevity ³ . The substantial heritability of general cognitive function is known to be polygenic, but it has had little explication in terms of the contributing genetic variants 4,5,6 . Here, we combined cognitive and genetic data fro...

Neurocognitive ability is a fundamental readout of brain function, and cognitive deficits are a critical component of neuropsychiatric disorders, yet neurocognition is poorly understood at the molecular level. In the present report, we present the largest genome-wide association studies (GWAS) of cognitive ability to date (N=107,207), and further e...

Schizotypal personality traits may increase proneness to psychosis and likely index familial vulnerability to schizophrenia (SZ), implying shared genetic determinants with SZ. Here, we sought to investigate the contribution of common genetic risk variation for SZ on self-reported schizotypy in 2 ethnically homogeneous cohorts of healthy young males...

Objective: The aim of the study was to compare the neurocognitive profile of unaffected first-degree relatives of schizophrenia patients with control individuals, controlling for different schizotypal traits. Method: One hundred and fifteen adult unaffected first-degree relatives of schizophrenia-spectrum patients and 122 controls were tested fo...

The complex nature of human cognition has resulted in cognitive genomics lagging behind many other fields in terms of gene discovery using genome-wide association study (GWAS) methods. In an attempt to overcome these barriers, the current study utilized GWAS meta-analysis to examine the association of common genetic variation (~8M single-nucleotide...

Introduction: Although cognitive deficits are consistent endophenotypes of schizophrenia and bipolar disorder, findings in psychotic bipolar disorder (BDP) are inconsistent. In this study we compared adult unaffected first-degree relatives of schizophrenia and BDP patients on cognition, psychopathology, social functioning and quality of life. Met...

Background: Increased schizotypal traits are observed in a percentage of the general population and in the schizophrenia-spectrum and have been associated with impairments in working memory. In this study we examined the effects of four schizotypal dimensions [Negative (NegS), Paranoid (ParS), Cognitive-Perceptual (CPS), Disorganized (DiS)] on exe...

Introduction: Studies assessing the effects of schizotypal dimensions (i.e., positive, negative, and disorganized) on cognitive functions have yielded mixed findings. In the present study, we administered an extensive battery of cognitive tasks to a community sample and defined the schizotypal dimensions according to a more analytical four-factor...

Background. The revised Temperament and Character Inventory (TCI-R) measures Cloninger’s psychobiological model of personality. The average effects of individual temperament and character traits have been associated with schizotypy and with impaired regulation of affect and cognition. We extended prior research by testing predictions about the asso...

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Schizotypy is defined as liability to schizophrenia, paralleling schizophrenic symptoms. Individuals with a family history of schizophrenia are at increased risk for illness development and their evaluation for schizotypy offers the advantage of examining the background of schizophrenia, while avoiding confounding variables. In this review, researc...

Inbreeding depression refers to lower fitness among offspring of genetic relatives. This reduced fitness is caused by the inheritance of two identical chromosomal segments (autozygosity) across the genome, which may expose the effects of (partially) recessive deleterious mutations. Even among outbred populations, autozygosity can occur to varying d...

Objective Schizotypy may be a forerunner of schizophrenia-spectrum disorders (SSD). In this study we examined for the first time the association between schizotypy and prefrontal function, quality of life (QoL) and general psychopathology (GenPsych) in 27 healthy subjects with no family history of SSD and 50 unaffected first-degree relatives of SSD...

Cognitive deficits and reduced educational achievement are common in psychiatric illness; understanding the genetic basis of cognitive and educational deficits may be informative about the etiology of psychiatric disorders. A recent, large genome-wide association study (GWAS) reported a genome-wide significant locus for years of education, which su...

Prepulse inhibition (PPI) of the startle reflex has been suggested as a candidate endophenotype for schizophrenia research, as it shows high heritability and has been found deficient in schizophrenia spectrum disorders. The objectives of the study were to 1) identify common genetic variants associated with baseline startle and PPI; 2) estimate the...

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Background: The Schizotypal Personality Questionnaire (SPQ) is a widely used scale for measuring schizotypal characteristics modeled on DSM-III-R criteria for schizotypal personality disorder (SPD). The aim of this study was to examine the factorial structure of the Greek SPQ, its factorial invariance across gender and different age groups and pos...

The CACNA1C rs1006737 risk A allele has been associated with affective psychoses and functional studies indicate that it is associated with increased hippocampal/amygdala activity during emotional face-processing. Here we studied the impact of the risk A allele on affective startle modulation. Hundred and ninety-four healthy males stratified for th...

Background: Cognitive impairment cuts across traditional diagnostic boundaries and is one of the most typical symptoms in various psychiatric and neurobiological disorders. Aims: The objective of this study was to examine the genetic association between 94 candidate genes, including receptors and enzymes that participate in neurotransmission, wi...

Introduction Although Positive (PS) and Negative Schizotypy (NS) are considered distinct entities, prefrontal dysfunction seems to be a common underlying mechanism. According to recent evidence, PS can be divided into Paranoid (ParS) and Cognitive-Perceptual (CPS). Objectives To explore NS', ParS' and CPS' profiles of prefrontal function/psychopath...

Schizotypy is defined as liability to schizophrenia, paralleling schizophrenic symptoms. Individuals with a family history of schizophrenia are at increased risk for illness development and their evaluation for schizotypy offers the advantage of examining the background of schizophrenia, while avoiding confounding variables. In this review, researc...

Three-dimensional chromosomal conformations regulate transcription by moving enhancers and reg-ulatory elements into spatial proximity with target genes. Here we describe activity-regulated long-range loopings bypassing up to 0.5 Mb of linear genome to modulate NMDA glutamate receptor GRIN2B expression in human and mouse prefrontal cortex. Distal i...

Background The single-nucleotide polymorphism (SNP) rs10503253, located within the CUB and Sushi multiple domains-1 (CSMD1) gene on 8p23.2, has reached genome-wide support as a risk factor for schizophrenia. There is initial but inconclusive evidence for a role of this variant in aspects of cognition. Methods We investigated the neurocognitive eff...

Background Our aim was to examine the role of Group Cognitive Behavioral Therapy (G-CBT) in increasing compliance to pharmacological treatment, and in preventing relapse in BPD type I (BPD-I) patients participating in group CBT at ‘Aghios Charalambos’ Mental Health Centre. Methods Forty patients [20 female and 20 male, age range 30–55 years, mean...

It has long been recognized that generalized deficits in cognitive ability represent a core component of schizophrenia (SCZ), evident before full illness onset and independent of medication. The possibility of genetic overlap between risk for SCZ and cognitive phenotypes has been suggested by the presence of cognitive deficits in first-degree relat...

Subjects with low/undetectable startle are usually excluded from startle studies but few reports not confounded by this factor, show reduced startle in healthy impulsive subjects, or clinical populations with disorders of affect and impulsivity but also in schizophrenia and its prodrome. We examined the relationship of startle reactivity including...

Neurons exhibit a constitutive level of nuclear factor-κB (NF-κB) signaling and this pathway plays a significant role in neurite outgrowth, activity-dependent plasticity, and cognitive function. Transcription factor analysis was performed in a microarray data set profiled in four different brain regions (n=54 comparison group; n=53 schizophrenia (S...

Part of the variation in personality characteristics has been attributed to the child-parent interaction and sub-optimal parenting has been associated with psychiatric morbidity. In the present study, an extensive battery of personality scales (Trait Anxiety Inventory, Behavioural Inhibition/Activation System questionnaire, Eysenck Personality Ques...

Psychosis has been suggested to represent a clinical manifestation of shared genetic liability between schizophrenia and bipolar disorder. Significant association was found between the CACNA1C risk allele and Paranoid Ideation in two independent cohorts of healthy individuals and risk for schizotypal personality disorder in a third cohort.

Schizophrenia and schizotypal personality disorder share common clinical profiles, neurobiological and genetic substrates along with Prepulse Inhibition and cognitive deficits; among those, executive, attention, and memory dysfunctions are more consistent. Schizotypy is considered to be a non-specific "psychosis-proneness," and understanding the re...

Neurocognitive deficits are a central part of the core features of schizophrenia and bipolar disorder as they affect multiple domains of cognitive function, are associated with but are independent of symptomatology, they are found even during phases of remission of the symptomatology and affect the functionality of the patients. Most of these defic...

Neuropsychopharmacology, the official publication of the American College of Neuropsychopharmacology, publishing the highest quality original research and advancing our understanding of the brain and behavior.

Genetic, neuroimaging, and molecular neurobiological evidence support the hypothesis that the disconnectivity syndrome in schizophrenia (SZ) could arise from failures of saltatory conduction and abnormalities at the nodes of Ranvier (NOR) interface where myelin and axons interact. To identify abnormalities in the expression of oligodendroglial gene...