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1.
Cogn Neuropsychiatry ; 29(1): 55-71, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38345024

RESUMEN

INTRODUCTION: Hallucinations can be experienced across multiple sensory modalities, but psychiatric studies investigating the cognitive mechanisms of hallucinations have been somewhat restricted to the auditory domain. This study explored the cognitive profiles of individuals experiencing multisensory hallucinations (MH) in schizophrenia-spectrum disorders (SSD) and compared these to those experiencing unimodal auditory hallucinations (AH) or no hallucinations (NH). METHODS: Participants included SSD patients (n = 119) stratified by current hallucination status (NH, AH, MH) and nonclinical controls (NCs; n = 113). Group performance was compared across several cognitive domains: speed of processing, attention, working memory, verbal learning, visual learning, reasoning and problem-solving, social cognition, and inhibition. RESULTS: The clinical groups performed worse than NCs but differences between the clinical groups were not evident across most cognitive domains. Exploratory analyses revealed that the MH group was more impaired on the visual learning task compared to the NH (but not AH) group. CONCLUSIONS: Preliminary results suggest that impaired visual learning may be related to MH. This could be attributed to the presence of visual hallucinations (VH), or greater psychopathology, in this group. However, replication is needed, as well as the investigation of other potential cognitive mechanisms of MH.


Asunto(s)
Esquizofrenia , Humanos , Esquizofrenia/complicaciones , Alucinaciones/psicología , Memoria a Corto Plazo , Atención/fisiología , Cognición
2.
Psychol Med ; 53(11): 5119-5126, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-35920237

RESUMEN

BACKGROUND: Schizophrenia and bipolar disorder are complex mental illnesses that are associated with cognitive deficits. There is considerable cognitive heterogeneity that exists within both disorders. Studies that cluster schizophrenia and bipolar patients into subgroups based on their cognitive profile increasingly demonstrate that, relative to healthy controls, there is a severely compromised subgroup and a relatively intact subgroup. There is emerging evidence that telomere shortening, a marker of cellular senescence, may be associated with cognitive impairments. The aim of this study was to explore the relationship between cognitive subgroups in bipolar-schizophrenia spectrum disorders and telomere length against a healthy control sample. METHODS: Participants included a transdiagnostic group diagnosed with bipolar, schizophrenia or schizoaffective disorder (n = 73) and healthy controls (n = 113). Cognitive clusters within the transdiagnostic patient group, were determined using K-means cluster analysis based on current cognitive functioning (MATRICS Consensus Cognitive Battery scores). Telomere length was determined using quantitative PCRs genomic DNA extracted from whole blood. Emergent clusters were then compared to the healthy control group on telomere length. RESULTS: Two clusters emerged within the patient group that were deemed to reflect a relatively intact cognitive group and a cognitively impaired subgroup. Telomere length was significantly shorter in the severely impaired cognitive subgroup compared to the healthy control group. CONCLUSIONS: This study replicates previous findings of transdiagnostic cognitive subgroups and associates shorter telomere length with the severely impaired cognitive subgroup. These findings support emerging literature associating cognitive impairments in psychiatric disorders to accelerated cellular aging as indexed by telomere length.


Asunto(s)
Trastorno Bipolar , Trastornos Psicóticos , Esquizofrenia , Humanos , Trastorno Bipolar/genética , Trastorno Bipolar/complicaciones , Esquizofrenia/genética , Esquizofrenia/complicaciones , Trastornos Psicóticos/genética , Trastornos Psicóticos/complicaciones , Cognición , Telómero
3.
Aust N Z J Psychiatry ; 56(3): 216-218, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-33715452

RESUMEN

Although the inclusion of individuals with lived experience is encouraged within the research process, there remains inconsistent direct involvement in many mental health fields. Within the eating disorders field specifically, there is a very strong and increasing presence of lived experience advocacy. However, due to a number of potential challenges, research undertaken in consultation or in collaboration with individuals with lived experience of an eating disorder is scarce. This paper describes the significant benefits of the inclusion of individuals with lived experience in research. The specific challenges and barriers faced in eating disorders research are also outlined. It is concluded that in addition to existing guidelines on working with lived experience collaborators in mental health research, more specific procedures are required when working with those with eating disorders.


Asunto(s)
Anorexia Nerviosa , Trastornos de Alimentación y de la Ingestión de Alimentos , Trastornos de Alimentación y de la Ingestión de Alimentos/terapia , Humanos , Salud Mental , Derivación y Consulta
4.
Proc Biol Sci ; 288(1964): 20212121, 2021 12 08.
Artículo en Inglés | MEDLINE | ID: mdl-34875191

RESUMEN

The thermotolerance-plasticity trade-off hypothesis predicts that ectotherms with greater basal thermal tolerance have a lower acclimation capacity. This hypothesis has been tested at both high and low temperatures but the results often conflict. If basal tolerance constrains plasticity (e.g. through shared mechanisms that create physiological constraints), it should be evident at the level of the individual, provided the trait measured is repeatable. Here, we used chill-coma onset temperature and chill-coma recovery time (CCO and CCRT; non-lethal thermal limits) to quantify cold tolerance of Drosophila melanogaster across two trials (pre- and post-acclimation). Cold acclimation improved cold tolerance, as expected, but individual measurements of CCO and CCRT in non-acclimated flies were not (or only slightly) repeatable. Surprisingly, however, there was still a strong correlation between basal tolerance and plasticity in cold-acclimated flies. We argue that this relationship is a statistical artefact (specifically, a manifestation of regression to the mean; RTM) and does not reflect a true trade-off or physiological constraint. Thermal tolerance trade-off patterns in previous studies that used similar methodology are thus likely to be impacted by RTM. Moving forward, controlling and/or correcting for RTM effects is critical to determining whether such a trade-off or physiological constraint exists.


Asunto(s)
Drosophila melanogaster , Ilusiones , Aclimatación/fisiología , Animales , Frío , Coma , Drosophila melanogaster/fisiología , Plásticos
5.
J Int Neuropsychol Soc ; 27(9): 916-928, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33342446

RESUMEN

OBJECTIVE: There is ongoing debate regarding the relationship between clinical symptoms and cognition in schizophrenia spectrum disorders (SSD). The present study aimed to explore the potential relationships between symptoms, with an emphasis on negative symptoms, and social and non-social cognition. METHOD: Hierarchical cluster analysis with k-means optimisation was conducted to characterise clinical subgroups using the Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms in n = 130 SSD participants. Emergent clusters were compared on the MATRICS Consensus Cognitive Battery, which measures non-social cognition and emotion management as well as demographic and clinical variables. Spearman's correlations were then used to investigate potential relationships between specific negative symptoms and emotion management and non-social cognition. RESULTS: Four distinct clinical subgroups were identified: 1. high hallucinations, 2. mixed symptoms, 3. high negative symptoms, and 4. relatively asymptomatic. The high negative symptom subgroup was found to have significantly poorer emotion management than the high hallucination and relatively asymptomatic subgroups. No further differences between subgroups were observed. Correlation analyses revealed avolition-apathy and anhedonia-asociality were negatively correlated with emotion management, but not non-social cognition. Affective flattening and alogia were not associated with either emotion management or non-social cognition. CONCLUSIONS: The present study identified associations between negative symptoms and emotion management within social cognition, but no domains of non-social cognition. This relationship may be specific to motivation, anhedonia and apathy, but not expressive deficits. This suggests that targeted interventions for social cognition may also result in parallel improvement in some specific negative symptoms.


Asunto(s)
Apatía , Esquizofrenia , Anhedonia , Cognición , Emociones , Humanos , Motivación , Esquizofrenia/complicaciones
6.
Int J Eat Disord ; 53(7): 1158-1165, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32476163

RESUMEN

OBJECTIVE: Emerging evidence suggests that the coronavirus (COVID-19) pandemic may be negatively impacting mental health. The impact on eating and exercise behaviors is, however, currently unknown. This study aimed to identify changes in eating and exercise behaviors in an Australian sample among individuals with an eating disorder, and the general population, amidst the COVID-19 pandemic outbreak. METHOD: A total of 5,469 participants, 180 of whom self-reported an eating disorder history, completed questions relating to changes in eating and exercise behaviors since the emergence of the pandemic, as part of the COLLATE (COvid-19 and you: mentaL heaLth in AusTralia now survEy) project; a national survey launched in Australia on April 1, 2020. RESULTS: In the eating disorders group, increased restricting, binge eating, purging, and exercise behaviors were found. In the general population, both increased restricting and binge eating behaviors were reported; however, respondents reported less exercise relative to before the pandemic. DISCUSSION: The findings have important implications for providing greater monitoring and support for eating disorder patients during the COVID-19 pandemic. In addition, the mental and physical health impacts of changed eating and exercise behaviors in the general population need to be acknowledged and monitored for potential long-term consequences.


Asunto(s)
Infecciones por Coronavirus/prevención & control , Ejercicio Físico/psicología , Conducta Alimentaria/psicología , Trastornos de Alimentación y de la Ingestión de Alimentos/psicología , Pandemias/prevención & control , Neumonía Viral/prevención & control , Cuarentena/psicología , Adulto , Australia/epidemiología , Betacoronavirus , COVID-19 , Infecciones por Coronavirus/psicología , Trastornos de Alimentación y de la Ingestión de Alimentos/epidemiología , Femenino , Humanos , Masculino , Salud Mental , Neumonía Viral/psicología , SARS-CoV-2 , Autoinforme
7.
Nutr Neurosci ; 23(2): 139-148, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29847303

RESUMEN

Objectives: Schizophrenia is a debilitating psychiatric illness associated with positive and negative symptoms as well as significant impairments in cognition. Current antipsychotic medications do not alleviate these cognitive deficits, and more effective therapeutic options are required. Increased oxidative stress and altered antioxidant levels, including glutathione (GSH) have been observed both in individuals with cognitive impairment and in people with schizophrenia. A GSH precursor, the antioxidant N-acetylcysteine (NAC) has been investigated as a novel treatment for the cognitive symptoms of schizophrenia, and recent research suggests that NAC may be a promising adjunctive treatment option. However, the current literature lacks integration as to why NAC may effectively improve cognition in schizophrenia. The present theoretical synthesis aimed to address this gap by examining the processes by which NAC may improve cognitive function in schizophrenia. Methods: The schizophrenia literature was reviewed in three key domains: cognitive impairment, the relationship between oxidative stress and cognition, and the efficacy of NAC as a novel treatment. This led to a theoretical analysis of the neurobiological processes by which NAC may improve cognition in schizophrenia. Results: This theoretical review concluded that improved cognition may result from a combination of factors, including decreased oxidative stress, neuroprotection of cognitive networks and an increase in glutamatergic modulation of the N-methyl-d-aspartate receptor system. Whilst a number of mechanisms by which NAC may improve cognition and symptoms in schizophrenia have been proposed, there is still limited understanding of the specific metabolic pathways involved and how they interrelate and modify specific symptomology. Discussion: Exploration of how NAC treatment may act to improve cognitive function could guide clinical trials by investigation of the specific neurotransmitter systems and processes involved, allowing for targeted neurological outcome measures. Future research would benefit from the investigation of both in vivo cortical GSH concentration and peripheral plasma GSH in a population of individuals with chronic schizophrenia.


Asunto(s)
Acetilcisteína/uso terapéutico , Cognición/efectos de los fármacos , Esquizofrenia/tratamiento farmacológico , Esquizofrenia/fisiopatología , Cognición/fisiología , Disfunción Cognitiva/tratamiento farmacológico , Disfunción Cognitiva/fisiopatología , Glutatión/fisiología , Humanos , Fármacos Neuroprotectores , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Receptores de N-Metil-D-Aspartato/efectos de los fármacos , Receptores de N-Metil-D-Aspartato/fisiología
8.
Aust N Z J Psychiatry ; 54(11): 1067-1071, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32746614

RESUMEN

During this unprecedented novel coronavirus (COVID-19) pandemic, there is an urgent need for empirical data to characterise its impact on the mental health and well-being of Australians. In this viewpoint, we outline a number of considerations for research on this topic, highlighting areas necessitating special attention, consideration of particular vulnerable groups and the need for longitudinal studies to track mental health fluctuations in the general population. We conclude by introducing the COLLATE (COvid-19 and you: mentaL heaLth in AusTralia now survEy) project, outlining its aims, addressing some considerations raised herein and detailing avenues for future research. Since the World Health Organization (WHO) declared the novel coronavirus (COVID-19) outbreak a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 (WHO, 2020), the COVID-19 pandemic has caused major upheaval both in Australia and globally. While the search for a vaccine continues, current efforts towards tackling the virus and limiting contagion in several nations have focused on social distancing and the shutdown of non-essential services. In Australia, the first case was reported on 13 January 2020 (COVID-19 National Incident Room Surveillance Team, 2020), the first death occurred on 24 February and a spate of progressive restrictions were enforced throughout the 2 weeks leading up to 31 March 2020 (COVID-19 National Incident Room Surveillance Team, 2020a).


Asunto(s)
Infecciones por Coronavirus/psicología , Salud Mental , Neumonía Viral/psicología , Salud Pública , Australia , COVID-19 , Necesidades y Demandas de Servicios de Salud , Humanos , Servicios de Salud Mental , Pandemias
9.
Aust N Z J Psychiatry ; 54(5): 453-466, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31826654

RESUMEN

OBJECTIVE: There is accumulating evidence that adjunctive treatment with N-acetylcysteine may be effective for schizophrenia. This study aimed to conduct a comprehensive meta-analysis examining the efficacy of randomised control trials investigating N-acetylcysteine as an adjunct treatment for schizophrenia and the first to investigate cognition as an outcome. METHODS: We systematically reviewed Medline, EmCare, PsycINFO, Embase, CINAHL Complete, China Knowledge Resource Integrated Database and the Cochrane Clinical Trials online registry for randomised control trials of N-acetylcysteine for schizophrenia. We undertook pairwise meta-analyses of N-acetylcysteine vs placebo for psychosis symptoms and cognition. RESULTS: Seven studies, including n = 220 receiving N-acetylcysteine and n = 220 receiving placebo, met inclusion criteria for the pairwise meta-analyses. Positive and Negative Syndrome Scale negative and total scores were significantly improved in the N-acetylcysteine group after 24 weeks of treatment. The cognitive domain of working memory improved with N-acetylcysteine supplementation. CONCLUSION: Evidence supports the notion that N-acetylcysteine may be a useful adjunct to standard treatment for the improvement of schizophrenia symptoms, as well as the cognitive domain of working memory. Treatment effects were observed at the later time point (⩾24 weeks), suggesting that longer interventions are required for the success of N-acetylcysteine treatment.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Acetilcisteína/uso terapéutico , Cognición , Humanos , Memoria a Corto Plazo , Ensayos Clínicos Controlados Aleatorios como Asunto , Esquizofrenia/tratamiento farmacológico
10.
Psychiatry Clin Neurosci ; 74(10): 542-549, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32602150

RESUMEN

AIM: The effects of social isolation measures used to control the spread of COVID-19 are negatively impacting the mental health of many. One of the consequences of exposure to disasters/pandemics is an increase in alcohol use. The current study aimed to examine what predisposing (distal) and pandemic-related (proximal) factors were associated with increased drinking in the wake of the COVID-19 pandemic. METHODS: On 1 April 2020, 5158 Australians completed a survey from the COvid-19 and you: mentaL heaLth in AusTralia now survEy (COLLATE) project, a nationwide study aimed at tracking key mental health concerns. Using logistic regression, distal (demographics and previous drinking behaviors) and proximal (employment, lifestyle factors, and mood) factors were assessed for their association with increased drinking since the onset of the COVID-19 pandemic. RESULTS: Distal factors, including heavier drinking pre-pandemic, middle age, and average or higher income, and proximal factors, including job loss, eating more, changes to sleep as well as stress and depression, were all associated with increased drinking in the COVID-19 pandemic environment. Female sex and self-reported history of mental illness became nonsignificant after proximal measures were added to the model. Living alone, exercise, anxiety, and status as an essential or health-care worker were not associated with increased drinking. CONCLUSION: These results provide guidance as to who might be targeted to receive support based on predisposing demographic factors and pre-pandemic drinking behavior. Second, they indicate what behaviors/factors accompany increased alcohol use and provide targets for psychosocial and psychoeducational supports to address these proximal factors.


Asunto(s)
Consumo de Bebidas Alcohólicas/epidemiología , COVID-19 , Depresión/epidemiología , Empleo/estadística & datos numéricos , Estrés Psicológico/epidemiología , Adolescente , Adulto , Afecto , Factores de Edad , Anciano , Consumo de Bebidas Alcohólicas/psicología , Ansiedad/epidemiología , Ansiedad/psicología , Australia/epidemiología , Depresión/psicología , Empleo/psicología , Ejercicio Físico/psicología , Conducta Alimentaria/psicología , Femenino , Humanos , Renta/estadística & datos numéricos , Estilo de Vida , Modelos Logísticos , Masculino , Persona de Mediana Edad , Distanciamiento Físico , Características de la Residencia/estadística & datos numéricos , Factores de Riesgo , Factores Sexuales , Sueño , Aislamiento Social/psicología , Estrés Psicológico/psicología , Desempleo/psicología , Desempleo/estadística & datos numéricos , Adulto Joven
11.
J Int Neuropsychol Soc ; 25(2): 174-183, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30558685

RESUMEN

Objectives: Antisaccade error rate has been proposed to be one of the most promising endophenotypes for schizophrenia. Increased error rate in patients has been associated with working memory, attention and other executive function impairments. The relationship between antisaccade error rate and other neuropsychological processes in patients compared to healthy controls has not been explored in depth. This study aimed to replicate the finding of heightened antisaccade error rate in patients and determine which cognitive processes were most strongly associated with antisaccade error rate in both patients and controls. In addition, the study investigated whether different antisaccade task paradigms engage different cognitive processes. Methods: One hundred and ninety-one participants (54 patients with schizophrenia/schizoaffective disorder and 137 controls) completed the antisaccade task, which included both gap and step task parameters. Neuropsychological measures were obtained using the MCCB and the Stroop task. Results: The current study replicated a pronounced antisaccade error rate deficit in patients. In patients, working memory variance was most significantly associated with antisaccade errors made during the step condition, while attentional processes were most associated with errors made during the gap condition. In controls, overall global cognitive performance was most associated with antisaccade rates for both gap and step conditions. Conclusions: The current study demonstrates that in schizophrenia patients, but not controls, elevated antisaccade error rate is associated with attention and working memory, but not with global cognitive impairment or psychopathological processes. Our novel findings demonstrate that the gap and step conditions of the antisaccade task engage different cognitive processes. (JINS, 2019, 25, 174-183).

12.
J Int Neuropsychol Soc ; 25(7): 750-760, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31104647

RESUMEN

OBJECTIVES: The Wisconsin Card Sorting Test (WCST) is a complex measure of executive function that is frequently employed to investigate the schizophrenia spectrum. The successful completion of the task requires the interaction of multiple intact executive processes, including attention, inhibition, cognitive flexibility, and concept formation. Considerable cognitive heterogeneity exists among the schizophrenia spectrum population, with substantive evidence to support the existence of distinct cognitive phenotypes. The within-group performance heterogeneity of individuals with schizophrenia spectrum disorder (SSD) on the WCST has yet to be investigated. A data-driven cluster analysis was performed to characterise WCST performance heterogeneity. METHODS: Hierarchical cluster analysis with k-means optimisation was employed to identify homogenous subgroups in a sample of 210 schizophrenia spectrum participants. Emergent clusters were then compared to each other and a group of 194 healthy controls (HC) on WCST performance and demographic/clinical variables. RESULTS: Three clusters emerged and were validated via altered design iterations. Clusters were deemed to reflect a relatively intact patient subgroup, a moderately impaired patient subgroup, and a severely impaired patient subgroup. CONCLUSIONS: Considerable within-group heterogeneity exists on the WCST. Identification of subgroups of patients who exhibit homogenous performance on measures of executive functioning may assist in optimising cognitive interventions. Previous associations found using the WCST among schizophrenia spectrum participants should be reappraised. (JINS, 2019, 25, 750-760).


Asunto(s)
Disfunción Cognitiva/fisiopatología , Función Ejecutiva/fisiología , Esquizofrenia/fisiopatología , Análisis y Desempeño de Tareas , Test de Clasificación de Tarjetas de Wisconsin , Adulto , Análisis por Conglomerados , Disfunción Cognitiva/clasificación , Disfunción Cognitiva/etiología , Femenino , Humanos , Masculino , Fenotipo , Esquizofrenia/complicaciones , Índice de Severidad de la Enfermedad , Adulto Joven
13.
Aust N Z J Psychiatry ; 53(3): 236-247, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-29707955

RESUMEN

OBJECTIVE: The personality characteristics and symptoms observed in schizophrenia are postulated to lie on a continuum, with non-clinical manifestations referred to as schizotypy. High schizotypy behaviours are argued to correspond with the three main clusters of symptoms in schizophrenia: positive, negative and cognitive/disorganised symptoms, yet there is limited empirical evidence to support this. This study aimed to investigate whether schizotypy dimensions significantly correlate with their respective schizophrenia symptomatology in the largest sample to date. METHODS: A total of 361 adults (103 patients with schizophrenia/schizoaffective disorder and 258 healthy controls) were assessed for schizotypy using the Oxford-Liverpool Inventory of Feelings and Experiences. The MATRICS Consensus Cognitive Battery supplemented by the Stroop task and Wisconsin Card Sorting Test was administered to all participants to obtain objective measurements of cognition. Schizophrenia symptomatology was assessed using the Positive and Negative Syndrome Scale in patients only. RESULTS: The results demonstrated significant correlations between the Oxford-Liverpool Inventory of Feelings and Experiences positive and negative subscales and their respective Positive and Negative Syndrome Scale subscales only, indicating that positive and negative schizotypy dimensions across patients and controls accurately reflect the respective schizophrenia symptomatology observed in patients. Cognitive performance did not correlate with cognitive/disorganised symptom dimensions of the Oxford-Liverpool Inventory of Feelings and Experiences or the Positive and Negative Syndrome Scale, indicating that cognitive impairment is an independent symptom dimension that requires objective cognitive testing. CONCLUSION: Collectively, the findings provide empirical evidence for the continuum theory and support the use of schizotypy as a model for investigating schizophrenia.


Asunto(s)
Esquizofrenia/diagnóstico , Psicología del Esquizofrénico , Trastorno de la Personalidad Esquizotípica/diagnóstico , Trastorno de la Personalidad Esquizotípica/psicología , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Escalas de Valoración Psiquiátrica , Test de Stroop , Test de Clasificación de Tarjetas de Wisconsin , Adulto Joven
15.
BMC Psychiatry ; 16(1): 320, 2016 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-27629871

RESUMEN

BACKGROUND: Clozapine is an effective treatment for a proportion of people with schizophrenia (SZ) who are resistant to the beneficial effects of other antipsychotic drugs. However, anything from 40-60 % of people on clozapine experience residual symptoms even on adequate doses of the medication, and thus could be considered 'clozapine resistant'. Agents that could work alongside clozapine to improve efficacy whilst not increasing the adverse effect burden are both desired and necessary to improve the lives of individuals with clozapine-resistant SZ. N-Acetylcysteine (NAC) is one such possible agent. Previous research from our research group provided promising pilot data suggesting the efficacy of NAC in this patient population. The aim of the study reported here is to expand this work by conducting a large scale clinical trial of NAC in the treatment of clozapine-resistant SZ. METHODS: This study is an investigator initiated, multi-site, randomised, placebo-controlled trial. It aims to include 168 patients with clozapine-resistant SZ, divided into an intervention group (NAC) and a control group (placebo). Participants in the intervention group will receive 2 g daily of NAC. The primary outcome measures will be the negative symptom scores of the Positive and Negative Syndrome Scale (PANSS). Secondary outcome measures will include: changes in quality of life (QoL) as measured by the Lancashire Quality of Life Profile (LQoLP) and cognitive functioning as measured by the total score on the MATRICS. Additionally we will examine peripheral and cortical glutathione (GSH) concentrations as process outcomes. DISCUSSION: This large scale clinical trial will investigate the efficacy of NAC as an adjunctive medication to clozapine. This trial, if successful, will establish a cheap, safe and easy-to-use agent (NAC) as a 'go to' adjunct in patients that are only partly responsive to clozapine. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registration Number: Current Randomised Controlled Trial ACTRN12615001273572 . The date of registration 23 November 2015.


Asunto(s)
Acetilcisteína/uso terapéutico , Clozapina , Esquizofrenia/tratamiento farmacológico , Psicología del Esquizofrénico , Adolescente , Adulto , Anciano , Antipsicóticos/uso terapéutico , Australia , Método Doble Ciego , Resistencia a Medicamentos , Femenino , Estudios de Seguimiento , Depuradores de Radicales Libres/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Nueva Zelanda , Calidad de Vida/psicología , Resultado del Tratamiento , Adulto Joven
17.
J Int Neuropsychol Soc ; 21(8): 629-38, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26306408

RESUMEN

Aberrant semantic processing has been linked to the etiology of formal thought disorder (TD) symptoms in schizophrenia. In this cross-sectional study, two prominent theories, overactivation and disorganized structure of semantic memory (SM), were examined in relation to TD symptoms using the continuum approach across two established semantic tasks (direct/indirect semantic priming and categorical fluency). The aim was to examine the validity of the two TD theories in relation to TD symptoms in schizophrenia. Greater direct and indirect priming, fluency productivity and category errors were expected if the data supported the overactivation theory. Reduced fluency productivity and increased category errors would be characteristic of disorganized storage. Fifty-seven schizophrenia/schizoaffective disorder patients and 48 controls completed a clinical assessment and the semantic tasks. There was significantly reduced direct priming in patients compared to controls (p<.05), while indirect priming was not significantly different; there was no association between TD and degree of priming. Patients produced more category-inappropriate words (p<.005) than controls, which was related to increasing severity of circumstantiality. The pattern of results was more indicative of a disorganized SM storage problem in this sample. This phenomenon may underlie some TD symptoms in general schizophrenia. The findings strengthen the relationship between SM deficits and TD symptoms, though this appears to differ between individual symptoms. The authors discuss the value of the continuum approach in addressing research questions in TD etiology. Given low levels of TD in this study, replication of these findings in a sample with greater TD is desirable.


Asunto(s)
Trastornos del Conocimiento/etiología , Trastornos del Lenguaje/etiología , Esquizofrenia/complicaciones , Psicología del Esquizofrénico , Semántica , Pensamiento/fisiología , Adulto , Análisis de Varianza , Aprendizaje por Asociación , Estudios Transversales , Femenino , Humanos , Pruebas del Lenguaje , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Escalas de Valoración Psiquiátrica
18.
Cogn Neuropsychiatry ; 19(1): 81-95, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-23822137

RESUMEN

INTRODUCTION: The semantic fluency task is described as a measure of semantic function and utilised in schizophrenia (SZ) research to demonstrate semantic deficits. Two meta-analyses support the efficacy of this task in measuring semantic function in SZ; however, a more recent meta-analysis suggests that executive dysfunction is the predominant determinant of semantic fluency performance in this group. By (1) matching the semantic and executive fluency tasks on discriminant validity, and (2) including an additional fluency task containing both semantic and executive elements (animals by size), this study aimed to determine whether semantic fluency is in fact an appropriate measure of semantic function in SZ. METHODS: Forty-two SZ participants and 40 healthy controls performed 3 fluency tasks: executive (F, A, S), semantic (body parts), and semantic/executive (animals by size). Performance on these tasks was analysed in two ways, (1) based on discriminant validity and (2) by matching output between the semantic and semantic/executive fluency tasks. RESULTS: When the semantic and executive fluency tasks were matched, executive fluency performance was either (1) mildly impaired or (2) not impaired in SZ. Both semantic and semantic/executive performance was impaired in SZ regardless of calculation. Group differences on the semantic/executive task remained when executive function was controlled for, but disappeared when semantic fluency effects were controlled for. CONCLUSIONS: The findings support earlier meta-analyses in finding that the semantic fluency task is a robust measure of semantic memory function in SZ.


Asunto(s)
Función Ejecutiva , Pruebas Neuropsicológicas , Psicología del Esquizofrénico , Semántica , Análisis y Desempeño de Tareas , Adulto , Femenino , Humanos , Masculino , Esquizofrenia/diagnóstico
19.
Cogn Neuropsychiatry ; 19(2): 134-48, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-23862769

RESUMEN

INTRODUCTION: Schizotypy is a useful schizophrenia analogue that controls for confounding factors such as medication and general intellectual decline. In the current study this analogue approach was used to examine implicit/explicit and direct/indirect semantic memory function. This is the first study to examine both implicit and explicit semantic access in the same schizotypy sample. METHODS: Participants completed four semantic tasks: (1) implicit indirect priming, (2) implicit direct priming, (3) explicit object (indirect) task, and (4) explicit association (direct) task. The schizophrenia literature suggests that semantic impairments are associated with thought disorder. As such, participants were divided into low (n=18) and high (n=18) schizotypy groups based on their responses to a thought disorder subscale of the Oxford Liverpool Inventory of Feelings and Experiences (O-Life) scale. RESULTS: In terms of implicit performance, the high schizotypy group demonstrated increased direct priming but nonsignificant indirect priming. The low schizotypy group demonstrated no significant difference in direct and indirect priming. Performance on the explicit tasks was equivalent between the two groups for direct stimuli. On the indirect explicit task, high schizotypy was associated with an increase in errors. CONCLUSIONS: Increased direct priming in high schizotypy is equivalent to that seen in schizophrenia, which has been interpreted as increased spreading of activation. Abnormal performance using the indirect stimuli was found across implicit and explicit versions. The relevance of these findings to schizophrenia are discussed.


Asunto(s)
Memoria Implícita , Esquizofrenia/fisiopatología , Psicología del Esquizofrénico , Semántica , Adulto , Estudios de Casos y Controles , Trastornos del Conocimiento , Femenino , Humanos , Masculino , Memoria , Inventario de Personalidad , Adulto Joven
20.
Psychiatry Res ; 339: 116013, 2024 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-38924902

RESUMEN

To understand the visual preponderance of perceived flaws in appearance in body dysmorphic disorder (BDD), the study of visual processing has been growing. Studies have focused on facial and other basic visual stimuli. The current literature does not provide evidence of consistent behavioural patterns, lacking an overarching body of work describing visual processing in BDD. This systematic review aims to characterise behavioural outcomes of visual processing anomalies and/or deficits in BDD. Articles were collected through online databases MEDLINE and PubMed, and were included if they comprised a clinical BDD group, and were published after 1990. Results indicate that individuals with BDD demonstrate deficits in emotional face processing, a possible overreliance on detail processing, aberrant eye-scanning behaviours, and a tendency to overvalue attractiveness. While findings consistently signal towards visual deficits in BDD, there is lack of clarity as to the type. This inconsistency may be attributed to heterogeneity within BDD samples and differences in experimental design (i.e., stimuli, tasks, conditions). There are difficulties distinguishing between BDD-associated deficits and those associated with OCD or eating disorders. A coherent framework, including sample characterisation and task design will seek to generate clear and consistent behavioural patterns to guide future treatments.

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