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Susan L Rossell

Publications and source records attributed to Susan L Rossell.

10 recordsLinked to original sources

An update on body dysmorphic disorder.

PURPOSE OF REVIEW: The present review provides an update on current research into body dysmorphic disorder. RECENT FINDINGS: Recent findings can be considered under four groupings: the classification of body dysmorphic disorder, its current inclusion under the somatoform disorders, and its relationship to obsessive compulsive disorder and other obsessive compulsive spectrum disorders; the psychotic 'variant' of body dysmorphic disorder, and whether it is simply a more severe form of the nonpsychotic type; the cognitive aspects of body dysmorphic disorder; and the treatment of body dysmorphic disorder, both in terms of pharmacological and psychological parameters. SUMMARY: Body dysmorphic disorder does not sit comfortably in the somatoform disorder category, and there is a good case for it being considered part of the obsessive compulsive spectrum, although it is not merely a subtype of obsessive compulsive disorder. Insight into the illness suggests that it represents a spectrum of disorders, and a categorical delineation of 'psychotic' and 'nonpsychotic' variants cannot be supported. We are beginning to understand more about the neurocognitive aspects of body dysmorphic disorder, but more research is required to assess which deficits/aberrations (if any) are exclusive to body dysmorphic disorder as an entity, and which are a reflection of broader phenomenological manifestations. Finally, the mainstay of treatment for body dysmorphic disorder remains behaviour/cognitive behaviour therapy and serotonin reuptake inhibitors; much more work is required to identify effective interventions for those patients who fail to respond to these treatment modalities.

Cognition Disorders↗

Are semantic deficits in schizophrenia due to problems with access or storage?

Semantic processing deficits are central to cognitive abnormalities in schizophrenia. Such semantic deficits may be related to either poor access or poor storage of semantic knowledge. 32 schizophrenia patients and 32 matched normal controls performed five semantic processing tasks that examined item-specific consistency over time, the word frequency effect and semantic priming. A subgroup of patients performed tasks on three separate occasions. It is generally assumed that a storage deficit is signalled by item-specific consistent performance, an exaggerated effect of word frequency, and the occurrence of hyperpriming; an access deficit is signalled by the absence of these effects. The data demonstrated item-specific consistency, a frequency effect and significant hyperpriming. The pattern is consistent with a storage deficit of semantic memory in schizophrenia.

Adult↗

Category fluency performance in patients with schizophrenia and bipolar disorder: The influence of affective categories.

Semantic fluency (SF) and phonological fluency (PF) were examined in large groups of schizophrenia patients, bipolar patients and controls. As well as standard SF categories (animals and food), fluency to two affective categories, happy and fear was measured, i.e. participants were asked to produce as many words as they could that resulted in or are associated with fear or happiness. Schizophrenia patients showed SF and PF deficits. Bipolar patients showed PF deficits. Thus, PF is argued to be a good cognitive marker in both disorders. Severity of delusions was related to SF performance in all patients. The patient groups showed different patterns on the affective categories compared to controls: the bipolar patients were better and produced more words, especially to the happiness category, and the schizophrenia patients were impaired and produced less words. The results suggest an interesting interaction between psychotic illnesses, fluency and emotion.

Adolescent↗

Are auditory-verbal hallucinations associated with auditory affective processing deficits?

We investigated whether the presence of auditory-verbal hallucinations (AVH) was associated with impaired auditory affect perception. Controls, schizophrenia patients with a history of AVH (AVH) or with no history of AVH (NAVH) completed four perceptual auditory affect tasks. The tasks used either non-verbal/non-semantic or verbal/semantic stimuli. AVH patients showed significant impairments on a non-verbal task requiring the recognition of environmental sounds, this was particularly so for the affective stimuli and not the neutral valance stimuli. Thus, confirming auditory affect deficits in AVH patients. AVH patients also showed reduced right ear performance on a dichotic listening task. Conversely, both patient groups showed impairments on auditory affect tasks that used verbal/semantic stimuli; as these tasks require proficient semantic processing we speculated that significant semantic impairments in schizophrenia masked the additional auditory affect deficits present in the AVH group. The overall results support the notion that patients with AVH have increased liability for auditory affect perception deficits.

Adult↗

Semantic priming after ketamine acutely in healthy volunteers and following chronic self-administration in substance users.

BACKGROUND: Ketamine is used acutely as a model of schizophrenia. It has been suggested that chronic ketamine may also mimic aspects of this disorder, in particular impaired cognitive function. As semantic processing deficits are considered central to cognitive impairments in schizophrenia, this study aimed to characterize semantic impairments following both acute and chronic ketamine. METHODS: We examined the acute effects of two doses of ketamine (Experiment 1) using a double-blind, placebo-controlled, independent group design with 48 volunteers. Ketamine's chronic effects (Experiment 2) were explored in 16 ketamine users and 16 poly-drug controls. A semantic priming task with a frequency (high and low) and stimulus onset asynchrony (SOA: short-200 msec, long-750 msec) manipulation was used. RESULTS: In Experiment 1, acute ketamine produced inverse priming at the long SOA. In Experiment 2, ketamine users showed inverse priming for low-frequency words at the long SOA compared to poly-drug controls. CONCLUSIONS: The inverse priming effect at the long SOA induced by acute ketamine was indicative of controlled processing impairments. In ketamine users, there was also an indication of controlled processing impairments. Decreased priming for low-frequency words suggested that long-term ketamine abuse results in damage to the semantic store.

Adult↗

Affective semantic priming in patients with schizophrenia.

Affective semantic priming was examined in normal controls and patients with schizophrenia using a lexical decision task with four affective categories of related word pairs: neutral, happy, fearful and sad. Results demonstrated a striking and reliable effect of affective category upon semantic priming. Neutral and happy prime targets yielded significant semantic priming. Fearful and sad pairs showed no or modest semantic priming facilitation. Schizophrenia patients did not differ from normal controls on their priming scores to any of the four affective categories. These results support the notion that the associative mechanisms that bind negative valence words are distinct in nature; they also clarify that patients with schizophrenia do not show increased sensitivity to affect, and more specifically negative affective context during priming paradigms. This study further indicates the importance of replicating novel findings and reporting negative results.

Adolescent↗

Semantic priming of different affective categories.

The authors investigated affective semantic priming using a lexical decision task with 4 affective categories of related word pairs: neutral, happy, fearful, and sad. Results demonstrated a striking and reliable effect of affective category on semantic priming. Neutral and happy prime-targets yielded significant semantic priming. Fearful pairs showed no or modest priming facilitation, and sad primes slowed reactions to sad targets. A further experiment established that affective primes do not have generalized facilitatory-inhibitory effects. The results are interpreted as showing that the associative mechanisms that support semantic priming for neutral words are also shared by happy valence words but not for negative valence words. This may reflect increased vigilance necessary in adverse contexts or suggest that the associative mechanisms that bind negative valence words are distinct.

Adult↗

The anatomy and time course of semantic priming investigated by fMRI and ERPs.

We combined complementary non-invasive brain imaging techniques with behavioural measures to investigate the anatomy and time course of brain activity associated with semantic priming in a lexical-decision task. Participants viewed pairs of stimuli, and decided whether the second item was a real word or not. There were two variables, the semantic relationship between the prime and the target (related or unrelated) and the interval between the onset of prime and target (200 or 1000 ms), to vary the degree of semantic expectancy that was possible during task performance. Behavioural results replicated the well-established finding that identification of the target is facilitated by a preceding semantically related prime. Event-related functional magnetic resonance imaging (efMRI) identified two brain areas involved in the semantic-priming effect. Activity in the anterior medial temporal cortex was diminished when target words were primed by semantically related words, suggesting involvement of this brain region during active semantic association or integration. In contrast, activity in the left supramarginal gyrus in the temporal-parietal junction was enhanced for target words primed by semantically related words. Brain areas influenced by the interval between prime and target words, and by the interaction between word interval and semantic priming were also identified. A parallel experiment using event-related potentials (ERPs) unveiled a striking difference in the time course of semantic priming as a function of expectancy. In line with previous reports, the primary effect of semantic priming on ERPs was the attenuation of the N400 component, in both short- and long-interval conditions. However, the priming effect started significantly earlier in the long-interval condition. Activity in the anterior medial temporal cortex has previously been shown to contribute to the N400 component, a finding that links the priming results obtained with efMRI and ERP methods.

Adult↗

Sex differences in functional brain activation during a lexical visual field task.

Functional MRI was used to investigate sex differences in brain activation during a paradigm similar to a lexical-decision task. Six males and 6 females performed two runs of the lexical visual field task (i.e., deciding which visual field a word compared with a pseudoword was presented to). A sex difference was noted behaviorally: The reaction time data showed males had a marginal right visual field advantage and women a left visual field advantage. Imaging results showed that men had a strongly left-lateralized pattern of activation, e.g., inferior frontal and fusiform gyrus, while women showed a more symmetrical pattern in language related areas with greater right-frontal and right-middle-temporal activation. The data show evidence of task-specific sex differences in the cerebral organization of language processing.

Adult↗

A computational morphometric MRI study of schizophrenia: effects of hallucinations.

Quantitative magnetic resonance imaging (MRI) studies in patients with schizophrenia have shown reliable deficits in global tissue volume as well as some regionally specific changes, particularly in the temporal and frontal lobes. Recent technical advances have enabled automated voxel-wise analyses, which have the advantage of facilitating whole brain coverage without the restrictions of anatomically defined regions of interest and imperfect rater reliability. We used such a method to estimate voxel composition from segmentation of bivariate, dual-echo spin-echo data in 72 men with schizophrenia. Of these, 41 had a prominent history of auditory-verbal hallucinations and 31 had no such history. The patients were compared with 32 age, gender, handedness and IQ matched healthy controls. The study revealed localized areas of reduced grey-matter tissue proportion aggregating around the medial temporal lobes, the insulae, orbito-frontal cortex including anterior cingulate, and the precuneus (and lingual) gyri, in the schizophrenia patients as a whole. There were also reductions in white-matter tissue proportion extending along much of the large anterior-posterior frontal tracts in the right hemisphere. Small regions of increased grey matter were also noted in the right inferior parietal lobe. A contrast between the hallucinator and non-hallucinator patient groups showed a single region of reduced grey-matter tissue proportion affecting the left insula and adjacent temporal lobe. These data confirm the utility of voxel-based morphometric methods in schizophrenia research and point towards disruption to a 'paralimbic' neural network, as underlying schizophrenic psychopathology in general, with abnormalities of the left insula specifically related to hallucinations.

Adult↗