1,721,668 research outputs found
Predictors of relapse in first-episode schizophrenia and related psychosis
No full textpublished_or_final_versionPsychiatryDoctoralDoctor of Philosoph
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Verbal information management in patients with schizophrenia and their healthy siblings : a novel paradigm for conversational analysis
No full textMotivations
Language has evolved as human’s primary communication tool. It allows us to flexibly manage the amount of information disclosed in communication to deal with complex social situations. Language impairment is a hallmark feature of schizophrenia, which could also be observed to a lesser extent in patients’ unaffected siblings. It significantly affects patients’ social functioning and clinical outcome. Despite ample evidence showing deficits across linguistic levels in schizophrenia, our understanding of patients’ performance in real-life communication, especially under non-cooperative (competitive or tactical) situations, is very limited. In this study we developed a novel method (conversational analysis paradigm, CAP) to investigate both cooperative and competitive communication performance in terms of verbal information value management among patients with schizophrenia and their unaffected siblings compared with healthy controls, and explored their relationships with clinical and cognitive functions.
Methods
Two studies were conducted. Study one consisted of a validation study (n=40) for
CAP and a cross-sectional (n=130) study in investigating verbal information management in schizophrenia and healthy participants. Performance was compared between patients with schizophrenia spectrum disorders (n=65) and matched healthy controls (n=65). Relationships between cognitive functions, clinical features, social competence, and CAP performance were also investigated. In study two, CAP performances were compared among 31 pairs of patients with schizophrenia, their healthy siblings and 31 matched healthy controls (total n=93) to examine verbal information management deficits as a trait in siblings. Schizotypal personality trait was also measured to investigate the potential relationship with CAP in siblings and healthy controls.
Results
The CAP test demonstrated good inter-rater reliability (ICC 0.82) and adequate internal consistency (Cronbach’s alpha 0.71--‐0.72). Patients showed poorer performance in verbal information management under both cooperative and competitive conditions, which were associated with psychotic symptoms and social functioning.
Patients’ poorer cooperatively communicating information, but not competitive controlling information, was associated with their cognitive functions. Performance of patients’ healthy siblings was intermediate between patients and healthy controls, especially during competitive communication. Verbal information management skills were correlated with schizotypal personality trait in siblings but not controls. More deviant verbal information management skills under competitive conditions were closely related to impaired immediate social network in patients and siblings.
Discussion
This study empirically documented the impaired verbal information management tactics in patients with schizophrenia and their healthy siblings compared using CAP. This specific domain of language impairment was related with cognitive functions, psychotic symptoms, real-life functioning, and schizotypal personality trait.
Significance
The current study has taken the first attempt to demonstrate an impairment of verbal information transfer in schizophrenia using a newly developed ecological test. Results of this study laid the groundwork for understanding language impairments related to schizophrenia, suggesting verbal information management as a candidate endophenotype of schizophrenia with intervention implications.published_or_final_versionPsychiatryDoctoralDoctor of Philosoph
Genetic architecture and risk prediction of complex diseases
No full textpublished_or_final_versionPsychiatryDoctoralDoctor of Philosoph
Determinants of long-term outcome in psychotic disorders: a 13-year prospective study
No full textMotivations
The growing interest in the investigation of longitudinal course and outcome of psychotic disorders grew from the Kraepelinian view of schizophrenia, which was considered a disease with progressive downhill course. With emerging evidence-based findings suggesting outcome heterogeneity, prospective studies have strived to identify factors influencing the course and outcome. The paucity of prospective long-term studies has prevented us from knowing the enduring impacts of predictors.
Using a prospective cohort of 153 psychosis patients, the study aimed to determine the outcome of global functioning, remission, functional recovery, and recovery at 13 years following the first-episode psychosis. Prognostic values of a range of baseline and early outcome predictors were examined. Specific research interests included the explorations of the enduring impact of duration of untreated psychosis (DUP), the longitudinal relationship between neurocognition and functional outcome, and the added predictive ability of early outcome predictors.
Methods
This study attempted to follow up the 153 patients at 13 years following their first episode onset of psychosis. Prior investigations collected a comprehensive profile of demographics, premorbid adjustment, clinical symptoms, and neurcognition at baseline. Early outcomes at 3 years including remission, relapse, primary negative symptoms, and unemployment were also ascertained. In this current investigation, living subjects were invited to an interview in order to assess their outcomes of global functioning, remission, functional recovery, and recovery at 13 years. Appropriate regression models were applied to identify predictors of long-term outcomes. Standardized mortality ratios (SMRs) for all-cause mortality and suicide were also determined.
Results
Ninety-six patients were successfully interviewed. Their mean (s.d.) score of global functioning was 64.3 (16.5). Considerable proportions of patients fulfilled criteria for remission (47%), functional recovery (33%), and recovery (16%) at 13 years. Higher level of global functioning was predicted by a married status at study entry and being in remission and employed at 3 years. Remission was predicted by a shorter DUP and better premorbid social adjustment. Functional recovery was predicted by better premorbid social adjustment, better baseline visual memory, and being employed at 3 years. No baseline and early outcome predictors of recovery could be identified. Addition of early outcome predictors significantly increased the variance explained for global functioning and improved model discrimination between patients who had functional recovery and those who had not. SMRs for all-cause mortality and suicide were 6.07 and 24.80, respectively.
Discussion
A prolonged DUP may intensify the progression of negative symptoms and lead to less likelihood of remission. The study has confirmed the enduring adverse impact of DUP but its reversibility is still in doubt. As the significance of visual memory in functional outcome has not received consistent support from literature, more prospective long-term studies are in need to re-examine the relationship. Early outcome predictors appear to be more relevant to functional outcome than clinical outcome.
Discussion
A prolonged DUP may intensify the progression of negative symptoms and lead to less likelihood of remission. The study has confirmed the enduring adverse impact of DUP but its reversibility is still in doubt. As the significance of visual memory in functional outcome has not received consistent support from literature, more prospective long-term studies are in need to re-examine the relationship. Early outcome predictors appear to be more relevant to functional outcome than clinical outcome.published_or_final_versionPsychiatryDoctoralDoctor of Philosoph
Blood brain-derived neurotrophic factor (BDNF) expression in normal humans and schizophrenic patients
No full textpublished_or_final_versionabstracttocPsychiatryMasterMaster of Philosoph
Suicidal ideation in patients with early psychosis
No full textpublished_or_final_versionabstracttocPsychiatryMasterMaster of Philosoph
A study of ideas and delusions of reference in schizophrenia: phenomenological, cognitive, andphysiological explorations
No full textpublished_or_final_versionPsychiatryDoctoralDoctor of Philosoph
Semantic networks and their disruptions in psychotic disorders
No full textBackground
Loosening of association and cognitive impairments are important core features of psychotic disorders (Bleuler, 1911/1950; Elvevåg & Goldberg, 2000). Over the past decades, research has identified various anomalies in linguistic functions in patients with psychosis. Nevertheless, despite numerous research into linguistic disruptions in psychosis, it remains inconclusive as to whether and how are language disrupted in psychosis, and what is the relationship between language disruptions and the other symptoms observed in psychosis, many of which are related to language. With the development of computational analysis methods, recent studies have attempted to apply these methods into the study of semantic disruptions in psychosis. The current study aimed to investigate the semantic network, its disruptions, and the factors behind these disruptions in patients by combining a continued word association task with semantic network analysis method. Using a longitudinal design, the current study also hopes to investigate whether semantic network changes across time as patients’ mental states change.
Methodology
Forty-two Cantonese-speaking patient subjects with psychotic disorders and 40 matching control subjects in Hong Kong have been included in the study. The study assessed the clinical, cognitive, functioning and semantic association profile of patients at baseline recruitment and at a 6-month follow-up. The study also collected cognitive and semantic association data from healthy control at baseline recruitment. The word association data collected using the continued word association task was analysed using an exploratory semantic network analysis method.
Results
First, the current study found that semantic networks properties differed between patients and controls. Patients’ network had less positive responses, and a denser network with slightly longer shortest path length, higher clustering coefficient, and lower modularity. Second, the study found that part of semantic network properties changed across time in patients alongside improvement in symptoms and functioning. Patients’ baseline semantic network was also less positive, denser, and with higher clustering coefficient than patients’ network at 6- month.
Discussion
This is the first attempt in studying the semantic network differences in Cantonese-speaking psychosis, anomalies in patients’ semantic association was found at an active psychotic state, when compared with controls. An across-time change was also noted in the study. This suggests that some of the semantic anomalies noted perhaps are state-dependent measures, which may change as the symptoms of patients change, while some other anomalies may remain as traits that remain unchanged despite the fluctuation in mental states.Li Ka Shing Prize, The Best M.Phil Thesis in the Faculties of Dentistry, Engineering, Medicine and Science (University of Hong Kong), 2017-2018published_or_final_versionPsychiatryMasterMaster of Philosoph
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