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In clinical settings, there is substantial evidence both clinically and empirically to suggest that approximately 50% of individuals with borderline personality disorder experience auditory verbal hallucinations. However, there is limited... more
In clinical settings, there is substantial evidence both clinically and empirically to suggest that approximately 50% of individuals with borderline personality disorder experience auditory verbal hallucinations. However, there is limited research investigating the phenomenology of these voices. The aim of this study was to review and compare our current understanding of auditory verbal hallucinations in borderline personality disorder with auditory verbal hallucinations in patients with a psychotic disorder, to critically analyse existing studies investigating auditory verbal hallucinations in borderline personality disorder and to identify gaps in current knowledge, which will help direct future research. The literature was searched using the electronic database Scopus, PubMed and MEDLINE. Relevant studies were included if they were written in English, were empirical studies specifically addressing auditory verbal hallucinations and borderline personality disorder, were peer revie...
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Patients who develop psychosis following a traumatic brain injury (PFTBI) show impaired neurocognition; however, the degree of impairment has not been empirically investigated using a standardised battery. We administered the Repeatable... more
Patients who develop psychosis following a traumatic brain injury (PFTBI) show impaired neurocognition; however, the degree of impairment has not been empirically investigated using a standardised battery. We administered the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to patients with PFTBI (n=10), and to three groups of controls: traumatic brain injury (TBI) (n=10), schizophrenia (n=23), and nonclinical controls (n=23). The results confirmed that the cognitive neuropsychological profile of dually-diagnosed patients with PFTBI is significantly and substantially impaired. Seventy per cent of patients with PFTBI received a neuropsychological classification between the "extremely low" and "low average" ranges. Group-wise analyses on the RBANS indices indicated that patients with PFTBI had the lowest (Immediate Memory, Attention, Delayed Memory, Total Score), or equal lowest (visuospatial, equivalent with schizophrenia patients) scores...
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The "jumping to conclusions" (JTC) bias has received significant attention in the schizophrenia and delusion literature as an important aspect of cognition characterising psychosis. The JTC bias has not been explored in... more
The "jumping to conclusions" (JTC) bias has received significant attention in the schizophrenia and delusion literature as an important aspect of cognition characterising psychosis. The JTC bias has not been explored in psychosis following traumatic brain injury (PFTBI). JTC was investigated in 10 patients with PFTBI using the beads task (ratios 85:15 and 60:40). Probabilistic predictions, draws-to-decision, self-rated decision confidence, and JTC bias were recorded. Responses from 10 patients with traumatic brain injury (TBI), 23 patients with schizophrenia, and 23 nonclinical controls were compared. Relationships were explored between draws-to-decision and current intelligence quotient, affective state, executive function, delusions (severity and type), and illness chronicity (duration). Groups were comparable on JTC measures. Delusion severity and type were not related to draws-to-decision for either trial. In the entire sample, executive function (reduced mental flexib...
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Meta-analytical findings have shown Cognitive Remediation (CR) effectiveness in augmenting cognitive and functional outcomes. Comparatively, a minimum amount of qualitative evidence has been reported to date. This study aimed to explore... more
Meta-analytical findings have shown Cognitive Remediation (CR) effectiveness in augmenting cognitive and functional outcomes. Comparatively, a minimum amount of qualitative evidence has been reported to date. This study aimed to explore the subjective experience of participants undertaking a CR trial. Twenty people with schizophrenia completed a questionnaire-facilitated interview, after having completed 20 h of CR. Thematic analysis was then used to identify codes and themes. Three themes were identified. In relation to reported benefits, all participants found the training to be a positive experience, with 70% having identified cognitive improvements, 45% improved motivation or confidence and 20% improved social skills. The role of the cognitive trainer in being supportive, adaptive and instructive was consistently reported as important, and most participants commented positively about the group format. Fewer participants had observed a transfer to real life settings, with improve...
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Anorexia Nervosa (AN) is a serious psychiatric illness characterised by a disturbance in body image, a fear of weight gain and significantly low body weight. The factors involved in the genesis and maintenance of AN are unclear, though... more
Anorexia Nervosa (AN) is a serious psychiatric illness characterised by a disturbance in body image, a fear of weight gain and significantly low body weight. The factors involved in the genesis and maintenance of AN are unclear, though the potential neurobiological underpinnings of the condition are of increasing interest. Through the investigation of functional connectivity of the brain at rest, information relating to neuronal communication and integration of information that may relate to behaviours and cognitive symptoms can be explored. The aim of this study was to investigate functional connectivity of the default mode network, and sensorimotor and visual networks in AN. 26 females with AN and 27 healthy control participants matched for age, gender and premorbid intelligence underwent a resting state functional magnetic resonance imaging scan. Default mode network functional connectivity did not differ between groups. AN participants displayed reduced functional connectivity b...
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Language dysfunction is proposed to relate to the speech disturbances in schizophrenia, which are more commonly referred to as formal thought disorder (FTD). Presently, language production deficits in schizophrenia are better... more
Language dysfunction is proposed to relate to the speech disturbances in schizophrenia, which are more commonly referred to as formal thought disorder (FTD). Presently, language production deficits in schizophrenia are better characterised than language comprehension difficulties. This study thus aimed to examine three aspects of language comprehension in schizophrenia: (1) the role of lexical processing, (2) meaning attribution for words and sentences, and (3) the relationship between comprehension and production. Fifty-seven schizophrenia/schizoaffective disorder patients and 48 healthy controls completed a clinical assessment and three language tasks assessing word recognition, synonym identification, and sentence comprehension. Poorer patient performance was expected on the latter two tasks. Recognition of word form was not impaired in schizophrenia, indicating intact lexical processing. Whereas single-word synonym identification was not significantly impaired, there was a tendency to attribute word meanings based on phonological similarity with increasing FTD severity. Importantly, there was a significant sentence comprehension deficit for processing deep structure, which correlated with FTD severity. These findings established a receptive language deficit in schizophrenia at the syntactic level. There was also evidence for a relationship between some aspects of language comprehension and speech production/FTD. Apart from indicating language as another mechanism in FTD aetiology, the data also suggest that remediating language comprehension problems may be an avenue to pursue in alleviating FTD symptomatology.
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Anorexia Nervosa (AN) has a mortality rate among the highest of any mental illness, though the factors involved in the condition remain unclear. Recently, the potential neurobiological underpinnings of the condition have become of... more
Anorexia Nervosa (AN) has a mortality rate among the highest of any mental illness, though the factors involved in the condition remain unclear. Recently, the potential neurobiological underpinnings of the condition have become of increasing interest. Saccadic eye movement tasks have proven useful in our understanding of the neurobiology of some other psychiatric illnesses as they utilise known brain regions, but to date have not been examined in AN. The aim of this study was to investigate whether individuals with AN differ from healthy individuals in performance on a range of saccadic eye movements tasks. 24 females with AN and 25 healthy individuals matched for age, gender and premorbid intelligence participated in the study. Participants were required to undergo memory-guided and self-paced saccade tasks, and an interleaved prosaccade/antisaccade/no-go saccade task while undergoing functional magnetic resonance imaging (fMRI). AN participants were found to make prosaccades of significantly shorter latency than healthy controls. AN participants also made an increased number of inhibitory errors on the memory-guided saccade task. Groups did not significantly differ in antisaccade, no-go saccade or self-paced saccade performance, or fMRI findings. The results suggest a potential role of GABA in the superior colliculus in the psychopathology of AN.
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Research Interests:
To utilise a comprehensive cognitive battery to gain a better understanding of cognitive performance in anorexia nervosa (AN). Twenty-six individuals with AN and 27 healthy control participants matched for age, gender and premorbid... more
To utilise a comprehensive cognitive battery to gain a better understanding of cognitive performance in anorexia nervosa (AN). Twenty-six individuals with AN and 27 healthy control participants matched for age, gender and premorbid intelligence, participated in the study. A standard cognitive battery, the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery, was used to investigate performance on seven cognitive domains with the use of 10 different tasks: speed of processing [Brief Assessment Of Cognition In Schizophrenia: Symbol Coding, Category Fluency: Animal Naming (Fluency) and Trail Making Test: Part A], attention/vigilance [Continuous Performance Test - Identical Pairs (CPT-IP)], working memory [Wechsler Memory Scale (WMS(®)-III): Spatial Span, and Letter-Number Span (LNS)], verbal learning [Hopkins Verbal Learning Test - Revised], visual learning [Brief Visuospatial Memory Test - Revised], reasoning and problem solving [Neurops...
Anorexia nervosa (AN) is a psychiatric condition characterised by a distortion of body image. However, whether individuals with AN can accurately perceive the size of other... more
Anorexia nervosa (AN) is a psychiatric condition characterised by a distortion of body image. However, whether individuals with AN can accurately perceive the size of other individuals' bodies is unclear. In the current study, 24 women with AN and 24 healthy control participants undertook two biological motion tasks while eyetracking was performed: to identify the gender and to indicate the walkers' body size. Anorexia nervosa participants tended to 'hyperscan' stimuli but did not demonstrate differences in how visual attention was directed to different body areas, relative to controls. Groups also did not differ in their estimation of body size. The hyperscanning behaviours suggest increased anxiety to disorder-relevant stimuli in AN. The lack of group difference in the estimation of body size suggests that the AN group was able to judge the body size of others accurately. The findings are discussed in terms of body image distortion specific to oneself in AN. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.
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Depression in schizophrenia is often associated with reduced life satisfaction. Yet, it is not clear how depression influences different functioning domains. The relative impact across objective and subjective quality of life (QOL) has... more
Depression in schizophrenia is often associated with reduced life satisfaction. Yet, it is not clear how depression influences different functioning domains. The relative impact across objective and subjective quality of life (QOL) has also not been clearly compared. This study sought to examine the differences in individual QOL indicators between schizophrenia patients with and without co-morbid depression. This was completed separately for objective and subjective QOL. 57 patients with schizophrenia/schizoaffective disorder were classified into groups with (DP: N=31, M=45.81, SD=10.29) and without depression (NDP: N=26, M=40.54, SD=11.00) using MADRS scores. Objective and subjective QOL was assessed using Lehman's (1988) QOL Interview using five domains: daily activities and functioning, family relations, social relations, safety and health. z-scores were created for these domains (objective and subjective) based on responses from 44 healthy controls (M=39.80, SD=13.94). Objectively, DP patients had significantly reduced social interaction frequency compared to HCs. Subjectively, DP patients had significantly poorer scores than HCs on all five domains, and additionally reported poorer satisfaction with daily activities and health compared with the NDP group. Presence of depression in schizophrenia results in reduced self-reported life satisfaction across a broad spectrum of QOL domains. Objectively, depression resulted in decreased interactions with friends and peers, i.e. greater social isolation. The findings support the need to continue developing and implementing peer support groups in schizophrenia, a challenging task especially in the face of depression. More broadly, the assessment of depression in other illnesses is recommended.
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Despite known overlaps in the pattern of cognitive impairments in individuals with bipolar disorder (BD), schizophrenia (SZ) and schizoaffective disorder (SZA), few studies have examined the extent to which cognitive performance validates... more
Despite known overlaps in the pattern of cognitive impairments in individuals with bipolar disorder (BD), schizophrenia (SZ) and schizoaffective disorder (SZA), few studies have examined the extent to which cognitive performance validates traditional diagnostic boundaries in these groups. Individuals with SZ (n=49), schizoaffective disorder (n=33) and BD (n=35) completed a battery of cognitive tests measuring the domains of processing speed, immediate memory, semantic memory, learning, working memory, executive function and sustained attention. A discriminant functions analysis revealed a significant function comprising semantic memory, immediate memory and processing speed that maximally separated patients with SZ from those with BD. Initial classification scores on the basis of this function showed modest diagnostic accuracy, owing in part to the misclassification of SZA patients as having SZ. When SZA patients were removed from the model, a second cross-validated classifier yielded slightly improved diagnostic accuracy and a single function solution, of which semantic memory loaded most heavily. A cluster of non-executive cognitive processes appears to have some validity in mapping onto traditional nosological boundaries. However, since semantic memory performance was the primary driver of the discrimination between BD and SZ, it is possible that performance differences between the disorders in this cognitive domain in particular, index separate underlying aetiologies.
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Systematic reviews and meta-analyses are a primary source of evidence when evaluating the benefit(s) of cognitive remediation (CR) in schizophrenia. These studies are designed to rigorously synthesize scientific literature; however,... more
Systematic reviews and meta-analyses are a primary source of evidence when evaluating the benefit(s) of cognitive remediation (CR) in schizophrenia. These studies are designed to rigorously synthesize scientific literature; however, cannot be assumed to be of high methodological quality. The aims of this report were to: 1) review the use of systematic reviews and meta-analyses regarding CR in schizophrenia; 2) conduct a systematic methodological appraisal of published reports examining the benefits of this intervention on core outcome domains; and 3) compare the correspondence between methodological and reporting quality. Electronic databases were searched for relevant articles. Twenty-one reviews met inclusion criteria and were scored according to the AMSTAR checklist-a validated scale of methodological quality. Five meta-analyses were also scored according to PRISMA statement to compare 'quality of conduct' with 'quality of reporting'. Most systematic reviews and meta-analyses shared strengths and fell within a 'medium' level of methodological quality. Nevertheless, there were consistent areas of potential weakness that were not addressed by most reviews. These included the lack of protocol registration, uncertainty regarding independent data extraction and consensus procedures, and the minimal assessment of publication bias. Moreover, quality of conduct may not necessarily parallel quality of reporting, suggesting that consideration of these methods independently may be important. Reviews concerning CR for schizophrenia are a valuable source of evidence. However, the methodological quality of these reports may require additional consideration. Enhancing quality of conduct is essential for enabling research literature to be interpreted with confidence.
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Research Interests: Cognitive Science, Schizophrenia, Magnetic Resonance Imaging, Positron Emission Tomography, Dyslexia, and 17 moreAnatomy, Temporal Lobe, Humans, Asymmetry, Human Brain, Meta Analysis, Cadaver, Computerised Tomography, Auditory Cortex, X ray Computed Tomography, Structure Function, Neurosciences, Functional Laterality, Magnetic resonance image, superior temporal gyrus, PLANUM TEMPORALE, and Sex Characteristics
The authors explored whether abnormal functional lateralization of temporal cortical language areas in schizophrenia was associated with a predisposition to auditory hallucinations and whether the auditory hallucinatory state would reduce... more
The authors explored whether abnormal functional lateralization of temporal cortical language areas in schizophrenia was associated with a predisposition to auditory hallucinations and whether the auditory hallucinatory state would reduce the temporal cortical response to external speech. Functional magnetic resonance imaging was used to measure the blood-oxygenation-level-dependent signal induced by auditory perception of speech in three groups of male subjects: eight schizophrenic patients with a history of auditory hallucinations (trait-positive), none of whom was currently hallucinating; seven schizophrenic patients without such a history (trait-negative); and eight healthy volunteers. Seven schizophrenic patients were also examined while they were actually experiencing severe auditory verbal hallucinations and again after their hallucinations had diminished. Voxel-by-voxel comparison of the median power of subjects' responses to periodic external speech revealed that this measure was reduced in the left superior temporal gyrus but increased in the right middle temporal gyrus in the combined schizophrenic groups relative to the healthy comparison group. Comparison of the trait-positive and trait-negative patients revealed no clear difference in the power of temporal cortical activation. Comparison of patients when experiencing severe hallucinations and when hallucinations were mild revealed reduced responsivity of the temporal cortex, especially the right middle temporal gyrus, to external speech during the former state. These results suggest that schizophrenia is associated with a reduced left and increased right temporal cortical response to auditory perception of speech, with little distinction between patients who differ in their vulnerability to hallucinations. The auditory hallucinatory state is associated with reduced activity in temporal cortical regions that overlap with those that normally process external speech, possibly because of competition for common neurophysiological resources.
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Research Interests:
The medial prefrontal cortex (mPFC) and the right temporo-parietal junction (rTPj) are highly involved in social understanding, a core area of impairment in autism spectrum disorder (ASD). We used fMRI to investigate sex differences in... more
The medial prefrontal cortex (mPFC) and the right temporo-parietal junction (rTPj) are highly involved in social understanding, a core area of impairment in autism spectrum disorder (ASD). We used fMRI to investigate sex differences in the neural correlates of social understanding in 27 high-functioning adults with ASD and 23 matched controls. There were no differences in neural activity in the mPFC or rTPj between groups during social processing. Whole brain analysis revealed decreased activity in the posterior superior temporal sulcus in males with ASD compared to control males while processing social information. This pattern was not observed in the female sub-sample. The current study indicates that sex mediates the neurobiology of ASD, particularly with respect to processing social information.
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Research Interests:
Anorexia Nervosa (AN) is a psychiatric illness associated with a number of personality disturbances. However, whether these personality characteristics are related to eating disorder symptomatology or emotion regulation is unclear. The... more
Anorexia Nervosa (AN) is a psychiatric illness associated with a number of personality disturbances. However, whether these personality characteristics are related to eating disorder symptomatology or emotion regulation is unclear. The aim of this study was to investigate these relationships. Twenty-four individuals with AN and 25 age- and premorbid intelligence-matched controls completed the Personality Diagnostic Questionnaire, and scores were correlated with measures of emotionality and negative mood states, and eating disorder symptomatology. AN was associated with increased scores on schizoid, borderline, avoidant, dependent, obsessive compulsive, negativistic and depressive personality dimensions, relative to controls. In AN, eating disorder symptomatology did not significantly correlate with scores on any personality dimension. However, a number of personality characteristics were found to correlate with negative mood states. The findings suggest that personality disturbances...
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Body dysmorphic disorder (BDD) is characterised by repetitive behaviours and/or mental acts occurring in response to preoccupations with perceived defects or flaws in physical appearance (American Psychiatric Association, 2013). This... more
Body dysmorphic disorder (BDD) is characterised by repetitive behaviours and/or mental acts occurring in response to preoccupations with perceived defects or flaws in physical appearance (American Psychiatric Association, 2013). This study aimed to investigate facial affect recognition in BDD using an integrated eye-tracking paradigm. Participants were 21 BDD patients, 19 obsessive-compulsive disorder (OCD) patients and 21 healthy controls (HC), who were age-, sex-, and IQ-matched. Stimuli were from the Pictures of Facial Affect (Ekman & Friesen, 1975), and outcome measures were affect recognition accuracy as well as spatial and temporal scanpath parameters. Relative to OCD and HC groups, BDD patients demonstrated significantly poorer facial affect perception and an angry recognition bias. An atypical scanning strategy encompassing significantly more blinks, fewer fixations of extended mean durations, higher mean saccade amplitudes, and less visual attention devoted to salient facia...
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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... more
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.
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Whether individuals with anorexia nervosa (AN) are able to accurately perceive emotions from faces of others is unclear. Furthermore, whether individuals with AN process images of their own face differently to healthy individuals has thus... more
Whether individuals with anorexia nervosa (AN) are able to accurately perceive emotions from faces of others is unclear. Furthermore, whether individuals with AN process images of their own face differently to healthy individuals has thus far not been investigated. Therefore, the aim of this study was to investigate facial affect processing and the processing of one's own face through measures of emotion identification, functional magnetic resonance imaging (fMRI) and eyetracking. Twenty-four females with AN and 25 matched healthy control participants were presented with an implicit emotion processing task during fMRI and eyetracking, followed by an explicit emotion identification task. The AN group were found to 'hyperscan' stimuli and avoided visually attending to salient features of their own face images. RESULTS of the fMRI revealed increased activity to own face stimuli in AN in the right inferior and middle temporal gyri, and right lingual gyrus. AN participants were not found to display emotion identification deficits to the standard emotional face stimuli. The findings are discussed in terms of increased anxiety to disorder-relevant stimuli in AN. Potential clinical implications are discussed in relation to the use of eyetracking techniques to improve the perception of self in AN.
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Body dysmorphic disorder (BDD) is characterised by (i) an excessive preoccupation with an imagined defect in appearance, as well as (ii) repetitive behaviours and/or mental acts that occur in response to the preoccupation. To date,... more
Body dysmorphic disorder (BDD) is characterised by (i) an excessive preoccupation with an imagined defect in appearance, as well as (ii) repetitive behaviours and/or mental acts that occur in response to the preoccupation. To date, neuropsychological investigations have been limited. This study examined performance on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), tapping into five indices of neurocognition: (i) Immediate Memory, (ii) Visuospatial Construction, (iii) Language, (iv) Attention, and (iv) Delayed Memory. Twenty-one BDD participants were compared with 19 obsessive-compulsive disorder (OCD) participants and 21 healthy controls (HC), who were age-, sex-, and IQ-matched. Results indicated the BDD and OCD groups demonstrated poor overall neuropsychological performance (i.e. total RBANS) as well as deficits on the indices of Immediate Memory and Attention. Further group differences involving the subtests of Story Memory, Digit Span, and Story ...
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To provide a clinically-focused review of the biological treatment of treatment-resistant obsessive compulsive disorder (OCD). There is a paucity of research on how to manage OCD patients who fail to respond adequately to first line... more
To provide a clinically-focused review of the biological treatment of treatment-resistant obsessive compulsive disorder (OCD). There is a paucity of research on how to manage OCD patients who fail to respond adequately to first line therapies. High-dose selective serotonin reuptake inhibitors (SSRIs) and clomipramine have good evidence-based data. Combinations of SSRIs have little support in clinical trials, but the combination of SSRIs and clomipramine can be helpful: careful clinical and cardiac monitoring is required. Certain adjunctive antipsychotics have a reasonable evidence base in OCD, but their use also needs to be weighed against the potential side effect burden. In patients with substantial generalised anxiety symptoms, clonazepam is worth considering. Of the other augmenting strategies, memantine and ondansetron appear useful in some cases, and are well tolerated. Topiramate might ameliorate compulsions to some degree, but it is less well tolerated. If all these strategi...
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Auditory verbal hallucinations (AVHs) are not uncommon in bipolar disorder (BD) and major depressive disorder (MDD), but there has been scant research in the area. The current paper aims to draw together and provide a critical overview of... more
Auditory verbal hallucinations (AVHs) are not uncommon in bipolar disorder (BD) and major depressive disorder (MDD), but there has been scant research in the area. The current paper aims to draw together and provide a critical overview of existing studies of AVHs in BD and MDD. A systematic review was undertaken using the search terms 'hallucinations' or 'hearing voices' in conjunction with 'bipolar disorder', 'mania' or 'manic-depressive' or 'major depressive disorder' or…
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Previous research has shown mild forms of the neurocognitive impairments seen in schizophrenia among healthy individuals exhibiting high schizotypal traits. This study aimed to explore associations between schizotypy and cognitive... more
Previous research has shown mild forms of the neurocognitive impairments seen in schizophrenia among healthy individuals exhibiting high schizotypal traits. This study aimed to explore associations between schizotypy and cognitive performance in an adult community sample. Ninety-five females and 79 males completed the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), which measures four separable aspects of schizotypy: cognitive disorganization, unusual experiences, introvertive anhedonia, and impulsive non-conformity. Subsequently, participants were administered a neurocognitive battery incorporating measures of executive skills including inhibition, cognitive flexibility, reasoning, and problem solving along with measures of attention and processing speed and both verbal and spatial working memory. In line with predictions, the current study found that higher scores on the subscales of unusual experiences, cognitive disorganization, and impulsive non-conformity rela...
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Cognitive performance in healthy persons varies widely between individuals. Sex differences in cognition are well reported, and there is an emerging body of evidence suggesting that the relationship between dopaminergic neurotransmission,... more
Cognitive performance in healthy persons varies widely between individuals. Sex differences in cognition are well reported, and there is an emerging body of evidence suggesting that the relationship between dopaminergic neurotransmission, implicated in many cognitive functions, is modulated by sex. Here, we examine the influence of sex and genetic variations along the dopaminergic pathway on aspects of cognitive control. A total of 415 healthy individuals, selected from an international consortium linked to Brain Research and Integrative Neuroscience Network (BRAINnet), were genotyped for two common and functional genetic variations of dopamine regulating genes: the catechol-O-methyltransferase [COMT] gene (rs4680) and the dopamine receptor D2 [DRD2] gene (rs6277). Cognitive measures were selected to explore sustained attention (using a continuous performance task), switching of attention (using a Trails B adaptation) and working memory (a visual computerised adaptation of digit spa...
The authors explored whether abnormal functional lateralization of temporal cortical language areas in schizophrenia was associated with a predisposition to auditory hallucinations and whether the auditory hallucinatory state would reduce... more
The authors explored whether abnormal functional lateralization of temporal cortical language areas in schizophrenia was associated with a predisposition to auditory hallucinations and whether the auditory hallucinatory state would reduce the temporal cortical response to external speech. Functional magnetic resonance imaging was used to measure the blood-oxygenation-level-dependent signal induced by auditory perception of speech in three groups of male subjects: eight schizophrenic patients with a history of auditory hallucinations (trait-positive), none of whom was currently hallucinating; seven schizophrenic patients without such a history (trait-negative); and eight healthy volunteers. Seven schizophrenic patients were also examined while they were actually experiencing severe auditory verbal hallucinations and again after their hallucinations had diminished. Voxel-by-voxel comparison of the median power of subjects' responses to periodic external speech revealed that this m...
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Our ability to make sense of emotional cues is of paramount importance for understanding state of mind and communicative intent. However, emotional cues often conflict with each other; this presents a significant challenge for people with... more
Our ability to make sense of emotional cues is of paramount importance for understanding state of mind and communicative intent. However, emotional cues often conflict with each other; this presents a significant challenge for people with schizophrenia. We conducted a theoretical review to determine the extent and types of impaired processing of emotion-related conflict in schizophrenia; we evaluated the relationship with medication and symptoms, and considered possible mediatory mechanisms. The literature established that people with schizophrenia demonstrated impaired function: (i) when passively exposed to emotion cues whilst performing an unrelated task, (ii) when selectively attending to one source of emotion cues whilst trying to ignore interference from another source, and (iii) when trying to resolve conflicting emotion cues and judge meta-communicative intent. These deficits showed associations with both negative and positive symptoms. There was limited evidence for antipsy...
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Research Interests:
Prepulse inhibition (PPI) is a measure of sensorimotor gating or information processing. Few studies have examined PPI in bipolar disorder (BD); two studies reported a PPI disruption and two reported no change. There are gender... more
Prepulse inhibition (PPI) is a measure of sensorimotor gating or information processing. Few studies have examined PPI in bipolar disorder (BD); two studies reported a PPI disruption and two reported no change. There are gender differences in PPI and within the clinical profile of BD, which may explain some of these discrepancies. Thus, the effect of gender on PPI in BD was the focus of the current study. Euthymic BD patients (14 male/15 female) were compared to age- and IQ-matched healthy control participants (16 male/16 female). Assessment of PPI included 21 pulse-alone trials (115 dB) and a total of 42 prepulse-pulse trials (seven of each prepulse: 74, 78, 86 dB) at two stimulus onset asynchrony levels (SOA: 60, 120 ms). There was a group x SOA and a group x gender interaction, reflecting that men with BD showed reduced PPI compared to control males at the 60-ms SOA (3% in BD vs. 26% in controls), but not the 120-ms SOA. In contrast, women with BD had significantly increased PPI compared to female controls at the 120-ms SOA (49% in BD vs. 29% in controls), but not the 60-ms SOA. Compared to control participants BD patients showed changes in PPI, which are gender-dependent; male BD participants had reduced PPI, whereas female BD participants had increased PPI. This gender difference highlights the need to consider men and women with BD as two distinct groups, at least in PPI studies.
Research Interests: Schizophrenia, Bipolar Disorder, Neuropsychopharmacology, Startle Reflex, Prepulse Inhibition, and 15 moreHumans, Female, Male, Gender Difference, PPI, Young Adult, Electromyography, Middle Aged, Adult, Sex Factors, Time Factors, Sensory Gating, Blinking, Case Control Studies, and Acoustic Stimulation
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ABSTRACT Individuals with a diagnosis of anorexia nervosa (AN) persistently engage in behaviors aimed to reduce their weight, which leads to severe underweight status, and death in up to 20 % of cases. Theoretical models applied in... more
ABSTRACT Individuals with a diagnosis of anorexia nervosa (AN) persistently engage in behaviors aimed to reduce their weight, which leads to severe underweight status, and death in up to 20 % of cases. Theoretical models applied in seminal investigations of the etiology of the disorder have focused on various constructs, including anhedonia – the reduced capacity to experience pleasure or reward. Anhedonia has been utilized as a model for multiple symptoms in AN including; food, i.e., the reduced capacity to experience reward associated with palatable foods, social impairments, i.e., reduced capacity to experience pleasure or reward from social interactions and exercise reward, i.e., excessive exercise, aimed to compensate for an anhedonic and dysphoric mood state. These symptom domains have been researched via various modalities including; behavioral and neuroimaging investigations. While there is an established literature on taste reward processing in AN, body image and particularly exercise and social reward have received comparatively less attention. Up to 80 % of individuals with AN reportedly excessively exercise, and social impairments are considered both causal and maintaining in the illness. Despite the relevance of reward and reinforcement in maintaining the illness, a unified model for reward processing in AN is yet to be agreed upon. The purpose of this chapter is to discuss the relevance of anhedonia as an explanatory framework for symptoms of AN.