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result(s) for
"Rossell, S. L."
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Characterizing cognitive heterogeneity on the schizophrenia–bipolar disorder spectrum
2017
Current group-average analysis suggests quantitative but not qualitative cognitive differences between schizophrenia (SZ) and bipolar disorder (BD). There is increasing recognition that cognitive within-group heterogeneity exists in both disorders, but it remains unclear as to whether between-group comparisons of performance in cognitive subgroups emerging from within each of these nosological categories uphold group-average findings. We addressed this by identifying cognitive subgroups in large samples of SZ and BD patients independently, and comparing their cognitive profiles. The utility of a cross-diagnostic clustering approach to understanding cognitive heterogeneity in these patients was also explored.
Hierarchical clustering analyses were conducted using cognitive data from 1541 participants (SZ n = 564, BD n = 402, healthy control n = 575).
Three qualitatively and quantitatively similar clusters emerged within each clinical group: a severely impaired cluster, a mild-moderately impaired cluster and a relatively intact cognitive cluster. A cross-diagnostic clustering solution also resulted in three subgroups and was superior in reducing cognitive heterogeneity compared with disorder clustering independently.
Quantitative SZ-BD cognitive differences commonly seen using group averages did not hold when cognitive heterogeneity was factored into our sample. Members of each corresponding subgroup, irrespective of diagnosis, might be manifesting the outcome of differences in shared cognitive risk factors.
Journal Article
Effects of Yoga and Aerobic Exercise on Verbal Fluency in Physically Inactive Older Adults: Randomized Controlled Trial (FitForAge)
by
Hoy, Sara
,
Pascoe, Michaela
,
Diwan, Vinod
in
Aerobic exercises
,
brain health
,
Care and treatment
2023
To compare the effects on verbal fluency of a supported yoga-based exercise intervention to an aerobic exercise intervention and a wait-list control group.
Eighty-two physically-inactive but otherwise healthy adults (mean age 72.5 years, range 65-85, 77% female) were recruited into a 12-week, three-group, parallel randomized controlled trial. Participants were supported to complete ≥3 Hatha yoga classes per/week or ≥3 structured aerobic exercise sessions/week. A wait-list control group continued usual daily activities only. Verbal fluency, including total-FAS, animals, and verbs, was assessed before and after interventions. Group effects were assessed using analysis of covariance (ANCOVA).
Twenty-seven participants were randomized to yoga, 29 to aerobic exercise and 26 to a waitlist. At 12-week follow-up, compared to baseline, there were increases in mean total-FAS in the yoga (+5.0 words,
=0.002) and aerobic exercise groups (+6.6 words,
=0.004). Mean total-FAS in the wait-list control group remained stable (-0.5 words,
=0.838). There were medium-magnitude estimated treatment effects on total-FAS for yoga versus wait-list control and aerobic exercise versus wait-list control: Hedges'
=0.51 (
=0.213) and 0.57 (
=0.098) respectively. In addition, small-to-medium magnitude estimated treatment effects were seen on animals and verbs for yoga versus wait-list control and aerobic exercise versus wait-list control:
=0.28 (
=0.155), 0.19 (
=0.766) and 0.50 (
=0.085), 0.59 (
=0.233) respectively.
Participation in yoga or aerobic exercise was associated with estimated improvements in verbal fluency compared to a non-active control group. Yoga and aerobic exercise may be promising approaches by which to promote cognitive function among older adults.
DRKS00015093, U1111-1217-4248.
Journal Article
Brain connectivity in body dysmorphic disorder compared with controls: a diffusion tensor imaging study
by
Brennan, S.
,
Maller, J. J.
,
Buchanan, B. G.
in
Adult
,
Adult and adolescent clinical studies
,
Anisotropy
2013
Several neuroimaging studies have investigated brain grey matter in people with body dysmorphic disorder (BDD), showing possible abnormalities in the limbic system, orbitofrontal cortex, caudate nuclei and temporal lobes. This study takes these findings forward by investigating white matter properties in BDD compared with controls using diffusion tensor imaging. It was hypothesized that the BDD sample would have widespread significantly reduced white matter connectivity as characterized by fractional anisotropy (FA).
A total of 20 participants with BDD and 20 healthy controls matched on age, gender and handedness underwent diffusion tensor imaging. FA, a measure of water diffusion within a voxel, was compared between groups on a voxel-by-voxel basis across the brain using tract-based spatial statistics within the FSL package.
Results showed that, compared with healthy controls, BDD patients demonstrated significantly lower FA (p < 0.05) in most major white matter tracts throughout the brain, including in the superior longitudinal fasciculus, inferior fronto-occipital fasciculus and corpus callosum. Lower FA levels could be accounted for by increased radial diffusivity as characterized by eigenvalues 2 and 3. No area of higher FA was found in BDD.
This study provided the first evidence of compromised white matter integrity within BDD patients. This suggests that there are inefficient connections between different brain areas, which may explain the cognitive and emotion regulation deficits within BDD patients.
Journal Article
Executive function in body dysmorphic disorder
by
Castle, D. J.
,
Dunai, J.
,
Labuschagne, I.
in
Adult
,
Adult and adolescent clinical studies
,
Anxiety
2010
Body dysmorphic disorder (BDD) is a poorly understood disorder that involves a preoccupation with imagined or minor bodily defects. Only a few studies of neuropsychological function have been conducted. Two previous studies have indicated executive dysfunction in BDD. The current study sought to further define these executive deficits.
Fourteen DSM-IV BDD patients and 14 age- and sex-matched control participants took part. Because of the high incidence of co-morbidity in BDD, patients with co-morbid Axis I disorders were not excluded. Control participants had no history of psychiatric illness. All participants completed the following executive function (EF) tests: Spatial Span (SS), Spatial Working Memory (SWM) and the Stockings of Cambridge (SOC) task. They also completed the Pattern Recognition (PR) test, a test of visual memory (VM).
BDD participants made significantly more between-search errors on the SWM task, an effect that increased with task difficulty. Between-search errors are an example of poor maintenance and manipulation of information. SOC results indicated slower subsequent thinking times (i.e. the time taken to plan) in BDD participants. There were no group differences in SS or PR scores. The severity of BDD, depressive or anxiety symptoms was not correlated with performance on any of the cognitive tasks.
The results of this study indicate that BDD patients have EF deficits in on-line manipulation, planning and organization of information. By contrast, spatial memory capacity, motor speed and visual memory were intact. Considered with evidence from lesion and neuroimaging studies, these results suggest frontal lobe dysfunction in BDD.
Journal Article
Insight: its relationship with cognitive function, brain volume and symptoms in schizophrenia
by
WOODRUFF, P. W. R.
,
SHAPLESKE, J.
,
DAVID, A. S.
in
Adult
,
Adult and adolescent clinical studies
,
Anhedonia
2003
Background. Lack of insight is frequently observed in schizophrenia. Relationships have been noted between poor insight, clinical symptoms and cognitive impairments but the findings are inconsistent. There have been some recent attempts to relate poor insight to neuro-anatomical measures. Method. We assessed insight, positive and negative symptoms of schizophrenia, cognitive performance, and whole brain volumes in a sample of 78 DSM-IV male schizophrenics and 36 normal male comparison subjects matched for age and IQ. Subjects underwent a dual-echo MRI brain scan to establish grey, white and whole brain volumes. Results. Poor Wisconsin Card Sorting Test performance inversely correlated with insight in schizophrenic patients, as did the symptoms alogia, anhedonia, avolition/apathy, affective flattening, inappropriate affect, thought disorder and delusions. The presence of inappropriate affect, delusions and thought disorder, showed the most significant impact on insight levels. There were no significant correlations between whole brain, white and grey matter volume and degree of insight. Conclusions. The results suggest that poor insight is significantly related to schizophrenic psychopathology, and confirm that there is a relationship between insight and executive performance. Awareness of illness is not related to any global brain measures, suggesting future investigations should pay attention to more specific cortical regions such as the frontal cortex.
Journal Article
Biopsychology of Physical Activity in People with Schizophrenia: An Integrative Perspective on Barriers and Intervention Strategies
by
Rossell, Susan L
,
Dark, Frances L
,
Chapman, Justin
in
Antipsychotics
,
autonomous motivation
,
behaviour change
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.
Journal Article
Classification of eating disorders: comparison of relative prevalence rates using DSM-IV and DSM-5 criteria
2015
DSM-5 contains substantial changes to eating disorder diagnoses. We examined
relative prevalence rates of DSM-IV and DSM-5 eating disorder diagnoses
using Eating Disorder Examination–Questionnaire diagnostic algorithms in 117
community out-patients. DSM-5 criteria produced a reduction in combined
‘other specified feeding or eating disorder’ and ‘unspecified feeding or
eating disorder’ diagnoses from 46% to 29%, an increase in anorexia nervosa
diagnoses from 35% to 47%, the same number of bulimia nervosa diagnoses and
a 5% rate of binge eating disorder diagnoses.
Journal Article
Relative associations of behavioral and physiological risks for cardiometabolic disease with cognition in bipolar disorder during mid and later-life: findings from the UK biobank
2024
Cardiometabolic disease risk factors are disproportionately prevalent in bipolar disorder (BD) and are associated with cognitive impairment. It is, however, unknown which health risk factors for cardiometabolic disease are relevant to cognition in BD. This study aimed to identify the cardiometabolic disease risk factors that are the most important correlates of cognitive impairment in BD; and to examine whether the nature of the relationships vary between mid and later life.
Data from the UK Biobank were available for 966 participants with BD, aged between 40 and 69 years. Individual cardiometabolic disease risk factors were initially regressed onto a global cognition score in separate models for the following risk factor domains; (1) health risk behaviors (physical activity, sedentary behavior, smoking, and sleep) and (2) physiological risk factors, stratified into (2a) anthropometric and clinical risk (handgrip strength, body composition, and blood pressure), and (2b) cardiometabolic disease risk biomarkers (CRP, lipid profile, and HbA1c). A final combined multivariate regression model for global cognition was then fitted, including only the predictor variables that were significantly associated with cognition in the previous models.
In the final combined model, lower mentally active and higher passive sedentary behavior, higher levels of physical activity, inadequate sleep duration, higher systolic and lower diastolic blood pressure, and lower handgrip strength were associated with worse global cognition.
Health risk behaviors, as well as blood pressure and muscular strength, are associated with cognitive function in BD, whereas other traditional physiological cardiometabolic disease risk factors are not.
Journal Article
N-Acetylcysteine (NAC) in Schizophrenia Resistant to Clozapine: A Double-Blind, Randomized, Placebo-Controlled Trial Targeting Negative Symptoms
by
Liu, Dennis
,
Dean, Olivia M
,
Harris, Anthony
in
Acetylcysteine - pharmacology
,
Antipsychotic Agents - adverse effects
,
Australia
2022
Abstract
Background and Hypothesis
Clozapine is the most effective antipsychotic for treatment-resistant schizophrenia, yet a significant proportion of individuals on clozapine continue to experience disabling symptoms, despite being treated with an adequate dose. There is a need for adjunct treatments to augment clozapine, notably for negative and cognitive symptoms. One such potential agent is the glutathione precursor N-acetylcysteine (NAC).
Study Design
A randomized double-blind, multi-center, placebo-controlled trial for clozapine patients with enduring psychotic symptoms (n = 84) was undertaken to investigate the efficacy of adjunctive NAC (2 g daily) for negative symptoms, cognition and quality of life (QoL). Efficacy was assessed at 8, 24, and 52 weeks.
Study Results
NAC did not significantly improve negative symptoms (P = .62), overall cognition (P = .71) or quality of life (Manchester quality of life: P = .11; Assessment of quality of life: P = .57) at any time point over a 1-year period of treatment. There were no differences in reported side effects between the groups (P = .26).
Conclusions
NAC did not significantly improve schizophrenia symptoms, cognition, or quality of life in treatment-resistant patients taking clozapine. This trial was registered with “Australian and New Zealand Clinical Trials” on the 30 May, 2016 (Registration Number: ACTRN12615001273572).
Journal Article
Is Body Dysmorphic Disorder Associated with Abnormal Bodily Self-Awareness? A Study Using the Rubber Hand Illusion
by
Enticott, Peter G.
,
Rossell, Susan L.
,
Kaplan, Ryan A.
in
Abnormal psychology
,
Abnormalities
,
Adolescent
2014
Evidence from past research suggests that behaviours and characteristics related to body dissatisfaction may be associated with greater instability of perceptual body image, possibly due to problems in the integration of body-related multisensory information. We investigated whether people with body dysmorphic disorder (BDD), a condition characterised by body image disturbances, demonstrated enhanced susceptibility to the rubber hand illusion (RHI), which arises as a result of multisensory integration processes when a rubber hand and the participant's hidden real hand are stimulated in synchrony. Overall, differences in RHI experience between the BDD group and healthy and schizophrenia control groups (n = 17 in each) were not significant. RHI strength, however, was positively associated with body dissatisfaction and related tendencies. For the healthy control group, proprioceptive drift towards the rubber hand was observed following synchronous but not asynchronous stimulation, a typical pattern when inducing the RHI. Similar drifts in proprioceptive awareness occurred for the BDD group irrespective of whether stimulation was synchronous or not. These results are discussed in terms of possible abnormalities in visual processing and multisensory integration among people with BDD.
Journal Article