University General - Research Publications
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ItemA biomarker and endophenotype for anorexia nervosa?(SAGE PUBLICATIONS LTD, 2022-08-01)OBJECTIVE: Recent research has suggested that a type of atypical eye movement, called square wave jerks, together with anxiety, may distinguish individuals with anorexia nervosa from those without anorexia nervosa and may represent a biomarker and endophenotype for the illness. The aim of this study was to identify the presence of this proposed marker in individuals currently with anorexia nervosa relative to healthy controls, and to identify the state independence and heritability of this putative marker by exploring whether it also exists in individuals who are weight-restored from anorexia nervosa and first-degree relatives (i.e. sisters of people with anorexia nervosa). METHODS: Data from 80 female participants (20/group: current anorexia nervosa, weight-restored from anorexia nervosa, sisters of people with anorexia nervosa and healthy controls) were analysed. Square wave jerk rate was acquired during a fixation task, and anxiety was measured with the State Trait Anxiety Inventory. RESULTS: Current anorexia nervosa, weight-restored from anorexia nervosa and sisters of people with anorexia nervosa groups made significantly more square wave jerks than healthy controls, but did not differ from one another. Square wave jerk rate and anxiety were found to discriminate groups with exceptionally high accuracy (current anorexia nervosa vs healthy control = 92.5%; weight-restored from anorexia nervosa vs healthy control = 77.5%; sisters of people with anorexia nervosa vs healthy control = 77.5%; p < .001). CONCLUSION: The combination of square wave jerk rate and anxiety was found to be a promising two-element marker for anorexia nervosa, and has the potential to be used as a biomarker or endophenotype to identify people at risk of anorexia nervosa and inform future treatments.
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ItemBiopsychology of Physical Activity in People with Schizophrenia: An Integrative Perspective on Barriers and Intervention Strategies.(Informa UK Limited, 2022)People with severe mental illness such as schizophrenia experience high physical comorbidity, leading to a 15-20-year mortality gap compared with the general population. Lifestyle behaviours such as physical activity (PA) play important roles in the quest to bridge this gap. Interventions to increase PA engagement in this population have potential to be efficacious; however, their effectiveness can be hindered by low participant engagement, including low adherence and high drop-out, and by implementation of interventions that are not designed to compensate for the cognitive and motivational impairments characteristic for this group. Moreover, and importantly, the negative symptoms of schizophrenia are associated with neurobiological changes in the brain, which-based on principles of biopsychology-can contribute to poor motivation and impaired decision-making processes and behavioural maintenance. To increase PA levels in people with schizophrenia, better understanding of these neurological changes that impact PA engagement is needed. This has the potential to inform the design of interventions that, through enhancement of motivation, could effectively increase PA levels in this specific population. Incorporating strategies that address the dopamine dysregulation associated with schizophrenia, such as boosting the role of reward and self-determined motivation, may improve long-term PA maintenance, leading to habitual PA. Consideration of motivation and behavioural maintenance is also needed to impart health benefits such as prevention of chronic disease, which is associated with currently low PA levels in this high metabolic risk population. Taking a biopsychological perspective, we outline the neural pathways involved in motivation that are impacted by schizophrenia and propose strategies for promoting motivation for and PA engagement from adoption to habit formation.
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ItemGender Differences in the Correlations between Childhood Trauma, Schizotypy and Negative Emotions in Non-Clinical Individuals.(MDPI AG, 2022-01-29)Early life trauma has a negative impact on the developing brain, and this can lead to a wide range of mental illnesses later in life. Childhood trauma is associated with increased psychotic symptoms and negative emotions such as depressive, anxiety, and stress symptoms in adulthood. Childhood trauma has also been shown to influence sub-clinical 'schizotypy' characteristics of psychosis in the general population. As it has been reported that mental health outcomes after early life trauma exposure are influenced by gender, the current study aimed to investigate the gender differences in the relationship between childhood trauma, schizotypy and negative emotions. Sixty-one non-clinical participants (33 men and 28 women) aged between 18 and 45 completed self-report questionnaires to measure early life trauma, schizotypy and negative emotions. Despite similar levels of childhood trauma in men and women, early life trauma in women was associated with increased schizotypy personality characteristics (Cognitive Disorganisation) and increased depression, anxiety and stress later in life, but no correlations were observed in men. Our findings suggest that the sociocultural and biological processes affected by early life adversities may differ between the genders. Women may be more vulnerable to the influence of childhood trauma, which may be associated with increased psychopathology later in life.
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ItemChanges of symptoms of eating disorders (ED) and their related psychological health issues during the COVID-19 pandemic: a systematic review and meta-analysis.(Springer Science and Business Media LLC, 2022-04-13)BACKGROUND: The COVID-19 pandemic and its related social restrictions have profoundly affected people's mental health. It can be assumed that symptomatic behaviors and mental health of individuals with eating disorders (ED) deteriorated during this time. To get a thorough overview, we conducted a systematic review and meta-analysis with the following aims: First, to provide a comprehensive overview of symptoms of ED during the COVID-19-related confinement; second, to identify psychological mechanisms which impacted the emergence and maintenance of ED symptoms; third, to describe changes of daily routine and changes of access to healthcare in individuals with ED during confinement. METHODS: We searched Embase, PubMed, and Scopus databases for observational studies published between January 1st, 2020, to July 1st, 2021, which investigated the symptomatology of ED during the COVID-19 pandemic. RESULTS: After the screening, 13 studies with 7848 participants were included in the present systematic review and meta-analysis. The overall pooled prevalence of exacerbation of binge eating, food restriction, purging behaviors, and concerns about food intake in the pooled sample of 7848 was 59.65% (95% CI: 49.30%; 69.60%), and the overall prevalence of improved symptoms of ED in the pooled sample of 741 individuals was 9.37% (95% CI: 3.92%; 16.57%). Furthermore, COVID-19-related social restrictions negatively impacted the psychological health, daily routines, and physical activity of individuals with ED. More specifically, symptoms of anxiety and depression related to ED were increased significantly over time. However, there were also positive aspects to the COVID-19 pandemic. The main positive consequences included more emotional support from the family, less pressure to engage in social activities, and more flexible meal planning. Individuals with ED reported having difficulties getting access to healthcare centers and using telemedicine. They also found a hard time communicating via online sessions. CONCLUSIONS: According to our interpretation, based on the data included in the systematic review and meta-analysis, the COVID-19 pandemic and its related social restrictions detrimentally impacted the mental health of majority of individuals with ED. Limited and impaired access to healthcare interventions appeared to have further exacerbated mental health issues of individuals with ED. Given this background, it seems that individuals with ED demand more attention during the COVID-19 crisis, and it is necessary to ensure that their course of treatment remains uninterrupted.
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ItemFrom core schemas about the self and others to voice phenomenology: Anxiety and depression affect voice hearers differently(WILEY, 2022-06)OBJECTIVES: Auditory verbal hallucinations (AVHs) occur as a symptom in various mental disorders, and show different phenomenological aspects, depending on their underlying psychopathology. Anxiety and depression, which are known to be involved in the development of AVHs, are suggested to amplify a vicious cycle in which negative interpretations of daily experiences feed into the formation of negative core schemas about the self and others. However, the way in which these variables interrelate is still unknown. Therefore, our aim was to determine the specific roles of anxiety and depression in the relationship between core schemas and emotional aspects of AVHs for three groups (non-clinical voice hearers, affective voice hearers and non-affective voice hearers). METHODS: Positive and negative core schemas of the self and others were tested as predictors of emotional distress due to AVHs, examining anxiety and depression separately as potential mediators. RESULTS: Results showed full mediating effects of depression in non-affective voice hearers in the relationship between negative core schemas and AVH distress, but not in affective voice hearers. Anxiety was not a mediator in any of the groups. CONCLUSIONS: These findings suggest different emotional mechanisms depending on the underlying psychopathology.
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ItemAssessing the dimensionality of scores derived from the Revised Formal Thought Disorder Self-Report Scale in schizotypy.(Public Library of Science (PLoS), 2022)The current work explored the dimensionality and convergent validity of responses to Barrera et al.'s (2015) 29-item Formal Thought Disorder-Self Scale (FTD-SS) obtained in two non-clinical samples. Exploratory factor analyses were conducted in Sample 1 (n = 324), yielding evidence of three correlated factors, although simple structure was not achieved until nine items were removed. Support for the correlated three factors model of responses to the revised 20-item scale (FTD-SS-R) was replicated when a confirmatory factor analysis was conducted in Sample 2 (n = 610). Finally, convergent associations were found between FTD-SS-R scores and scores from other schizotypy measures across both samples, though these measures only explained half of the variance in FTD-SS-R scores. Additional research is needed to evaluate the appropriateness of the items and incremental validity of the scale in non-clinical samples.
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ItemNo Preview AvailablePsychosis and Hopelessness Mediate the Relationship Between Reduced Sleep and Suicidal Ideation in Schizophrenia Spectrum Disorders(ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2022-01-01)OBJECTIVE: Suicide is a major cause of death amongst individuals with schizophrenia spectrum disorders (SSD). Despite numerous risk factors being identified, accurate prediction of suicidality and provision of tailored and effective treatment is difficult. One factor that may warrant particular attention as a contributor to increased psychopathology and suicidality in SSD is disturbed sleep. Sleep disturbances have been reliably linked to greater levels of suicidal ideation and are highly prevalent amongst individuals with SSD. This study aimed to examine if reduced sleep duration and psychopathology are associated with increased suicidal ideation. METHOD: One-hundred and eighteen adults with chronic SSD living within the community participated in this cross-sectional study. Psychosis symptoms were assessed using the Positive and Negative Syndrome Scale. Items 4 and 10 from the Montgomery-Asperg Depression Rating Scale and Item 2 from the Calgary Depression Scale for Schizophrenia were used to assess reduced sleep duration, current suicidal ideation, and hopelessness, respectively. All measures were rated concurrently. RESULTS: A hierarchical logistic regression revealed that greater acute sleep disturbances were associated with increased suicidal ideation and this relationship was found to be uniquely mediated by both positive symptom severity and hopelessness. CONCLUSION: These results suggest that individuals with SSD who exhibited disrupted or disordered sleep, positive symptoms and/or hopelessness should be routinely screened for suicidal thinking. Furthermore, interventions that effectively target sleep disruptions may provide much-needed action against suicidal ideation.HIGHLIGHTSReduced sleep found to be associated with increased suicidal ideationThis was uniquely mediated by both hopelessness and positive symptomsMore regular screening of sleep problems in schizophrenia is needed.
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ItemNo Preview AvailableCharacterisation of Deficits and Sex Differences in Verbal and Visual Memory/Learning in Bipolar Disorder(CAMBRIDGE UNIV PRESS, 2023-01)OBJECTIVE: Cognitive impairment is consistently reported in bipolar disorder (BD), but few studies have characterised which memory component processes are affected. Further, it is unknown whether the component processes underlying memory impairment are moderated by sex. The present study examined diagnosis and sex differences in both verbal and visual memory/learning domains in patients with BD and psychiatrically healthy controls. METHOD: Verbal and visual memory/learning were measured using the Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-Revised (BVMT-R). 114 patients with BD (n = 50 males, n = 64 females), were compared to 105 psychiatrically healthy controls (n = 42 males, n = 63 females). RESULTS: Patients with BD had worse performance in verbal and visual immediate and total recall, verbal and visual delayed free recall, and verbal recognition discrimination scores, but there were no group differences in learning slopes and cumulative learning index scores. There were trends for BD females to outperform BD males in visual memory/learning free recall and cumulative learning, but these results did not survive multiple testing correction. These findings did not change in a secondary sensitivity analysis comparing only strictly euthymic BD patients to controls (n = 64). CONCLUSION: The present study found trait-like verbal and visual memory/learning impairment in BD that was attributable to deficient encoding and/or consolidation processes rather than deficits in learning. We did not find marked sex differences in either visual or verbal memory/learning measures, although some trend level effects were apparent and deserve exploration in future studies.
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ItemNo Preview AvailableUnderstanding familial liability for emotion regulation difficulties in bipolar disorder(CAMBRIDGE UNIV PRESS, 2022-10)BACKGROUND: There has been relatively limited work focused on understanding whether relatives of individuals with bipolar disorder (BD) have difficulties in the regulation of emotion, particularly in relation to perceptions about whether emotions can be effectively regulated, or trait behaviours that acknowledge emotions as self-regulators themselves. In this study, we assessed the presence and extent of difficulties in these dimensions of emotion regulation in individuals with BD compared to unaffected first-degree biological relatives (FDR) for the first time. METHODS: In total, 161 participants, including euthymic individuals with BD, unaffected FDRs, and healthy controls, were compared on the Difficulties in Emotion Regulation Scale (DERS) - a multi-dimensional measure of habitual emotion regulation. Clinical data were also collected and examined in relation to DERS scores in a secondary analysis. RESULTS: In the BD group, difficulties were evident for most dimensions of emotion regulation as measured by the DERS; and correlated with an earlier onset of illness and more mood episodes. FDRs displayed generally normal emotion regulation, except in terms of their beliefs that emotions can be effectively regulated; on this dimension, their reported difficulty was intermediate to the BD group and controls. CONCLUSION: Habitual emotion regulation difficulties in BD persist irrespective of mood state, are related to the course of illness, and should be targeted in psychological interventions. Further, the perception that emotions cannot be effectively regulated during times of distress seems to represent an endophenotype for BD.
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ItemEvidence that a working memory cognitive phenotype within schizophrenia has a unique underlying biology(ELSEVIER IRELAND LTD, 2022-11)It is suggested studying phenotypes within the syndrome of schizophrenia will accelerate understanding the complex molecular pathology of the disorder. Supporting this hypothesis, we have identified a sub-group within schizophrenia with impaired working memory (WM) and have used Affymetrix™ Human Exon 1.0 ST Arrays to compare their blood RNA levels (n=16) to a group of with intact WM (n=18). Levels of 72 RNAs were higher in blood from patients with impaired WM, 11 of which have proven links to the maintenance of different aspects of working memory (cognition). Overall, changed gene expression in those with impaired WM could be linked to cognition through glutamatergic activity, olfaction, immunity, inflammation as well as energy and metabolism. Our data gives preliminary support to the hypotheses that there is a working memory deficit phenotype within the syndrome of schizophrenia with has a biological underpinning. In addition, our data raises the possibility that a larger study could show that the specific changes in gene expression we have identified could prove to be the biomarkers needed to develop a blood test to identify those with impaired WM; a significant step toward allowing the use of personalised medicine directed toward improving their impaired working memory.