DRC: a dual route cascaded model of visual word recognition and reading aloud

This article describes the Dual Route Cascaded (DRC) model, a computational model of visual word recognition and reading aloud. The DRC is a computational realization of the dual-route theory of reading, and is the only computational model of reading that can perform the 2 tasks most commonly used to study reading: lexical decision and reading aloud. For both tasks, the authors show that a wide variety of variables that influence human latencies influence the DRC model's latencies in exactly the same way. The DRC model simulates a number of such effects that other computational models of reading do not, but there appear to be no effects that any other current computational model of reading can simulate but that the DRC model cannot. The authors conclude that the DRC model is the most successful of the existing computational models of reading.

Basic fibroblast growth factor from human keratinocytes is a natural mitogen for melanocytes

To survive and proliferate in pure culture, human melanocytes require basic fibroblast growth factor (bFGF) and cAMP. Without these factors, even in the presence of serum, the cells die. Melanocytes cultured in the presence of keratinocytes, however, survive for weeks without added bFGF and cAMP. We show here that the growth factor for melanocytes produced by human keratinocytes is bFGF because its activity can be abolished by neutralizing antibodies to bFGF and by a bFGF synthetic peptide that inhibits the binding of the growth factor to its receptor. The melanocyte mitogen in keratinocytes is cell associated and increases after irradiation with ultraviolet B. Northern blots reveal bFGF gene transcripts in keratinocytes but not melanocytes. These studies demonstrate that bFGF elaborated by keratinocytes in vitro sustains melanocyte growth and survival, and they suggest that keratinocyte-derived bFGF is the natural growth factor for normal human melanocytes in vivo.

Human keratinocytes contain mRNA indistinguishable from monocyte interleukin 1 alpha and beta mRNA. Keratinocyte epidermal cell-derived thymocyte-activating factor is identical to interleukin 1

Keratinocytes produce an IL-1 like factor termed epidermal cell-derived thymocyte-activating factor (ETAF). In this study, we show that ETAF and IL-1 are identical by the following criteria: Both normal and malignant human keratinocytes contain mRNAs identical to monocytic IL-1 alpha and IL-1 beta mRNA, as determined by an S1 nuclease protection assay; and IL-1 activity in medium conditioned by these cells can be neutralized by antibodies specific for human IL-1. The IL-1 alpha and IL-1 beta mRNAs can be identified in cultured human keratinocytes in the absence of identifiable stimulation; this basal level of mRNA can be further induced to accumulate with certain defined stimuli. Cultured normal human keratinocytes (HFKs) contain 2-4 times more IL-1 alpha than IL-1 beta mRNA; in contrast, human peripheral blood monocytes contain 10-20 times more IL-1 beta than IL-1 alpha mRNA. The IL-1 activity released by these HFK can be neutralized by an antibody that neutralizes both alpha and beta IL-1, but not by an antibody that neutralizes only IL-1 beta. While human monocytes produce a large excess of IL-1 beta after appropriate stimulation, these data suggest that IL-1 alpha is a major (and may be the predominant) form of IL-1 produced by human keratinocytes.

Use of cultured epidermal autografts and dermal allografts as skin replacement after burn injury

An adult with burns over 55% of body surface area (80% of which were third degree) was treated with cadaver skin allografts. The allografts were later abraded to remove allogeneic epidermis and resurfaced with autogenous keratinocyte cultures. Complete reconstitution of skin, consisting of epidermal autograft and dermal allograft, was achieved.

Composite autologous-allogeneic skin replacement: development and clinical application

A major unsolved problem in skin restoration in severe burns is replacement of lost dermis. We report the development and clinical application of a composite grafting technique in which allogeneic skin is the source of dermis, and cultured autologous keratinocytes generate epidermis. Excised burn wounds are resurfaced with unmatched allograft. Immunosuppression from the burn and reduced immunoreactivity of the allograft permit successful allograft engraftment. Keratinocyte cultures are initiated from the patient. Allogeneic epidermis is removed, and the dermal bed is resurfaced with keratinocyte cultures. The allogeneic dermis promotes rapid (less than 7 days) stratification, maturation, and integration of the cultures and the synthesis of anchoring fibrils. One case followed 11 months has shown no evidence of rejection. We reason that removal of the epidermis from allograft eliminates the majority of cells constitutively expressing alloclass II antigens, leaving behind a viable allogeneic dermal bed that serves as an ideal substrate for engraftment and integration of keratinocyte cultures but does not initiate rejection.

Mentalising, schizotypy, and schizophrenia

Despite accumulating evidence that patients with schizophrenia perform poorly in mentalising tasks, doubts remain about the primacy of the role played by defective mentalising in schizophrenia. This study investigated the relationship between mentalising ability and self-reported schizotypal traits in non-clinical adults who reported no history of psychiatric illness in order to test two counter-proposals: (1) defective mentalising is a primary cause of psychotic symptoms in schizophrenia; and (2) defective mentalising in schizophrenia is a secondary consequence of the chronic asociality that is typical of general psychiatric illness. Mentalising ability was tested using a false-belief picture sequencing task that has been used elsewhere to demonstrate poor mentalising in patients with schizophrenia. Evidence of selective mentalising deficits in high schizotypal non-clinical subjects discounted the view that defective mentalising is restricted to psychiatric illness and strengthened the case for continuity models of psychosis-proneness. Furthermore, evidence that poor mentalisers in the normal population are more likely to self-report psychotic-like traits, as well as asocial or idiosyncratic behaviours, refuted suggestions that defective mentalising is linked solely to asocial symptomatology and supported the view that defective mentalising may have a fundamental role to play in the explanation of psychotic symptoms. In order to specify what that role might be, alternative theoretical accounts of defective mentalising were tested. Neither executive planning deficits nor failure to inhibit cognitively salient inappropriate information could adequately explain the pattern of selective mentalising deficits found in high schizotypal non-clinical subjects. Our findings suggest that there exists a domain-specific cognitive module that is dedicated to inferring and representing mental states which, when dysfunctional, causes defective mentalising that manifests phenomenologically in psychotic-like traits and impoverished social awareness of variable expression and ranging severity.

Disturbed communication in schizophrenia: the role of poor pragmatics and poor mind-reading

BACKGROUND

Disturbed speech in schizophrenia may reflect pragmatic deficits of expressive language. Pragmatic comprehension deficits also occur in schizophrenia. This study investigated whether poor 'mind-reading' (i.e. a general difficulty with inferring and monitoring other people's thoughts) causes pragmatic language impairments of both expression and comprehension in patients with schizophrenia.

METHOD

Mind-reading (or theory of mind) was tested in patients with schizophrenia and in healthy controls using a false-belief picture-sequencing task. Pragmatic comprehension skills were assessed using a test of non-literal speech interpretation. Clinical ratings of formal thought disorder (FTD) indexed the expressive language deficits of patients. To control for possible contributory effects of executive dysfunction, inhibitory control was tested using capture picture-sequences and executive-planning was tested using the Tower of London task.

RESULTS

False-belief picture-sequencing, understanding of irony and understanding of metaphors were all selectively impaired in the patients. Poor mind-reading (indexed by high error rate in sequencing false-belief stories) was associated with poor understanding of irony, but was unrelated to poor understanding of metaphors. Whereas poor appreciation of irony and poor mind-reading were associated with high ratings of positive formal thought disorder, high ratings of negative formal thought disorder were associated with poor understanding of metaphors and executive dysfunction.

CONCLUSIONS

Whereas poor mind-reading may contribute to positive aspects of formal thought disorder and impaired appreciation of irony in patients with schizophrenia; negative features of formal thought disorder and poor understanding of metaphors appear better explained by abnormal semantics. Overall, the findings of this study support the view that the functional basis of formal thought disorder in schizophrenia is not unitary.

The neuropsychological basis of hypersociability in Williams and Down syndrome

People with Williams syndrome (WS) display indiscriminate approach toward strangers in everyday life. People with Down syndrome (DS) can also do so, but to a lesser degree. Inappropriate approach behavior is also characteristic of people with acquired amygdala damage and people with acquired frontal lobe impairment; given this, the developmental disorder of social approach seen in WS and perhaps also DS might be due to poor emotion recognition (due to abnormal amygdala functioning) or poor control of behavior (due to frontal lobe abnormality). A third account of this developmental disorder of social cognition can be couched in terms of heightened salience for social stimuli. We explored these three hypotheses by testing emotion recognition, social approach and frontal lobe functioning in people with WS and DS. Overall, our results were inconsistent with predictions from the amygdala and social salience hypotheses. In contrast, results from a battery of neuropsychological tasks suggested that abnormal social approach in WS and DS in everyday life is best explained by frontal lobe impairment, in particular, poor response inhibition.

Jumping to Conclusions About the Beads Task? A Meta-analysis of Delusional Ideation and Data-Gathering

It has been claimed that delusional and delusion-prone individuals have a tendency to gather less data before forming beliefs. Most of the evidence for this "jumping to conclusions" (JTC) bias comes from studies using the "beads task" data-gathering paradigm. However, the evidence for the JTC bias is mixed. We conducted a random-effects meta-analysis of individual participant data from 38 clinical and nonclinical samples (n = 2,237) to investigate the relationship between data gathering in the beads task (using the "draws to decision" measure) and delusional ideation (as indexed by the "Peters et al Delusions Inventory"; PDI). We found that delusional ideation is negatively associated with data gathering (r(s) = -0.10, 95% CI [-0.17, -0.03]) and that there is heterogeneity in the estimated effect sizes (Q-stat P = .03, I(2) = 33). Subgroup analysis revealed that the negative association is present when considering the 23 samples (n = 1,754) from the large general population subgroup alone (r(s) = -0.10, 95% CI [-0.18, -0.02]) but not when considering the 8 samples (n = 262) from the small current delusions subgroup alone (r(s) = -0.12, 95% CI [-0.31, 0.07]). These results provide some provisional support for continuum theories of psychosis and cognitive models that implicate the JTC bias in the formation and maintenance of delusions.

Defective Self and/or Other Mentalising in Schizophrenia: A Cognitive Neuropsychological Approach

The mentalising abilities of schizophrenic patients and normal controls were tested using picture sequencing and story-telling tasks that required subjects to infer causal mental states in story characters, and a recall task that required subjects to dissociate subjective mental states from objective realities. Selective mentalising deficits were found in some patients. For other patients, general sequencing errors, "sensory" mentalising, and poor recall of symbolic representations suggested more profound problems. Task results were best accounted for by dissociable cognitive abnormalities, rather than graded dysfunction of a central mentalising mechanism. Symptom profiles of patient subgroups and correlations between task measures and clinical ratings linked these cognitive abnormalities to specific symptoms. General sequencing difficulty was associated with both poverty symptoms and reality distortion, suggesting that two mechanisms may underpin such errors: one, inability to manipulate symbolic representations, being linked to poverty; the other, failure to critically evaluate plausible cause-and-effect, being linked to reality distortion. There was some evidence that defective self-monitoring underpins thought disorder. Impaired metarepresentation was linked to the autisticlike symptoms of flat affect, social dysfunction, and alogia, rather than reality distortion. Implications of these findings are discussed with respect to theoretical and methodological issues confronting current schizophrenia research.

Reasoning anomalies associated with delusions in schizophrenia

Deluded people differ from nondeluded controls on attributional style questionnaires and probabilistic-reasoning and theory-of-mind (ToM) tasks. No study to date has examined the relations between these 3 reasoning anomalies in the same individuals so as to evaluate their functional independence and potentially inform theories of delusion formation. We did so in 35 schizophrenic patients with a history of delusions, 30 of whom were currently deluded, and 34 healthy controls. Compared with healthy controls, patients showed (a) a jumping-to-conclusions bias and a bias to overadjust when confronted with a change of evidence on probabilistic-reasoning tasks, (b) an excessive externalizing attributional bias, and (c) performance deficits on 3 ToM tasks. Probabilistic-reasoning and ToM measures correlated, while attributional-bias scores were independent of other task measures. A general proneness to delusional ideation correlated with probabilistic-reasoning and ToM measures, while externalizing bias was unrelated to the study measures of delusional ideation. Personalizing bias associated specifically with paranoia across the clinical and nonclinical participants. Findings are consistent with a common underlying mechanism in schizophrenia which contributes to the anomalies on probabilistic-reasoning and ToM tasks associated with delusions. We speculate that this mechanism is impairment of the normal capacity to inhibit "perceived reality" (the evidence of our senses), a capacity that evolved as part of the "social brain" to facilitate intersubjective communication within a shared reality.

"Sleights of mind": delusions, defences, and self-deception

Two different modes of theorising about delusions are explored. On the one hand is the motivational approach, which regards delusions as serving a defensive, palliative, even potentially adaptive function. On the other, is the cognitive deficit approach, which conceptualises delusions as explicitly pathological, involving abnormalities in ordinary cognitive processes. The former approach, prominently exemplified by the psychoanalytic tradition, was predominant historically, but has been challenged in recent years by the latter. Some grievances against psychoanalytic theory are briefly discussed, and it is argued that although the reasons for psychoanalysis falling into scientific disrepute are partly justified, the psychodynamic notion that motivation has access to the mechanisms of belief formation is of potentially crucial theoretical utility. A variety of possible syntheses of the two theoretical modes are therefore explored, in the belief that the most comprehensive account of delusions will involve a theoretical unification of both styles of explanation. Along the way, an attempt is made to locate the notions delusion, defence, and self-deception in a shared theoretical space.

Visual perspective-taking and schizotypy: evidence for a simulation-based account of mentalizing in normal adults

Modular theory-of-mind accounts attribute poor mentalizing to disruption of a cognitive module dedicated to computing higher-order representations of primary representations (metarepresentations). Since metarepresentational capacity is needed to mentalize about other people's beliefs but is not needed to judge visual perspectives (which can be done by mentally rotating primary representations of seen objects), this view predicts that visual perspective-taking will be intact in individuals with selective mentalizing impairments. Counter to that prediction, this study found evidence of disturbed visual perspective-taking in normal adults who score higher on the personality variable of schizotypy and who are known to be relatively poor mentalizers (despite intact ability to inhibit salient inappropriate information in order to reason consequentially on the basis of hypothetical states, other than mental states). Whereas high-schizotypal adults and low-schizotypal adults did not differ in their ability to judge item questions (asking the relative location of array features), high-schizotypal adults performed more poorly than low-schizotypal adults in judging appearance questions (asking how an array would appear from another perspective) under viewer-rotation instructions (asking subjects to imagine moving themselves relative to a fixed array) and performed better than low-schizotypal adults in judging appearance questions under array-rotation instructions (asking subjects to imagine rotating an array relative to their own fixed viewer position). Based on these and other findings we conclude that poor mentalizing in normal adults is better understood as an impairment of perspective-taking (visual and/or cognitive) and introduce the concept of allocentric simulation to explain the functional basis of this perspective-taking impairment.

A double-blind randomized controlled trial of oxytocin nasal spray and social cognition training for young people with early psychosis

Social-cognitive deficits contribute to poor functional outcomes in early psychosis; however, no effective pharmacological treatments exist for these problems. This study was the first to investigate the efficacy of an extended treatment of oxytocin nasal spray combined with social cognition training (SCT) to improve social cognition, clinical symptoms, and social functioning in early psychosis. In a double-blind, randomized, placebo-controlled, between-subjects trial, 52 individuals (aged 16-35 years) diagnosed with an early psychosis schizophrenia-spectrum illness were recruited. Participants received oxytocin (24 International Units) or placebo nasal spray twice-daily for 6 weeks, combined with group SCT (2 × 1 hour weekly sessions for 6 weeks). An additional dose of oxytocin was administered before each weekly session. Assessments were conducted at baseline, post-treatment, and at 3-month follow-up. Primary outcomes included the Reading the Mind in the Eyes Test, the Scale for the Assessment of Positive and Negative Symptoms, and the Social Functioning Scale. Secondary outcomes included self-report and behavioral assessments of social cognition, symptom severity, and social functioning. Results showed that on all primary and secondary outcomes, there was no benefit of oxytocin nasal spray treatment in comparison to placebo. Exploratory post hoc analysis suggested that increased use of nasal spray was, however, associated with reductions in negative symptoms in the oxytocin condition only. This study represents the first evaluation of oxytocin treatment for early psychosis. Although results suggest no benefit of oxytocin treatment, results also highlight an urgent need to consider nasal spray delivery and dose-related variables for future clinical trials.

Empathetic perspective-taking is impaired in schizophrenia: evidence from a study of emotion attribution and theory of mind

INTRODUCTION

Schizophrenia and autism are clinically distinct yet both disorders are characterised by theory of mind (ToM) deficits. Autistic individuals fail to appreciate false beliefs, yet understand the causal connections between behavioural events and simple emotions. Findings of this type have promoted the view that ToM deficits in autism reflect a domain-specific difficulty with appreciating the representational nature of epistemic mental states (i.e., beliefs and intentions and not emotions). This study examines whether the same holds true for schizophrenia.

METHODS

A picture-sequencing task assessed capacity to infer false beliefs in patients with schizophrenia and healthy controls. To assess emotion attribution, participants were shown cartoon strips of events likely to elicit strong emotional reactions in story characters. Characters' faces were blanked out. Participants were instructed to think about how the characters would be feeling in order to match up the cards depicting facial affect appropriately. Participants later named emotions depicted in facial affect cards.

RESULTS

Patients were as capable as controls of identifying cartoon facial expressions, yet had greater difficulties with: (a) attributing emotions based on circumstances; and (b) inferring false beliefs.

CONCLUSIONS

Schizophrenia patients, unlike autistic individuals, suffer a domain-general difficulty with empathetic perspective-taking that affects equally their appreciation of other people's beliefs, percepts, and emotions.

Recognition of metaphor and irony in young adults: the impact of schizotypal personality traits

Patients with schizophrenia demonstrate two dissociable impairments of pragmatic language comprehension: (1) an insensitivity to irony, which is associated with poor theory-of-mind (i.e. a difficulty with inferring other people's thoughts); and (2) poor recognition of metaphors, which may reflect degraded semantics. This study investigated whether non-clinical high-schizotypal adults show similar impairments of pragmatic language. Thirty-six university students completed the Raine Schizotypal Personality Questionnaire, the Wechsler Memory Scale Logical-Memories subtest, Raven's Progressive Matrices and a story comprehension task that tested the ability to discriminate between incongruous statements and appropriate uses of ironical, metaphorical or literal speech. Counter to the pattern found for patients, high-schizotypal adults were just as capable as low-schizotypal adults of identifying appropriate metaphors, suggesting a discontinuity between schizophrenia and schizotypy for the metaphor-recognition problem. This study's finding of intact metaphor recognition in high-schizotypal adults contrasts with previous findings of poor proverb comprehension in these individuals and is interpreted in terms of different semantic processes required for recognizing and interpreting metaphors. Consistent with the pattern found for patients, high-schizotypal adults were significantly impaired in their ability to appreciate when a literally contradictory utterance could be interpreted as ironical, suggesting continuity between schizophrenia and schizotypy for the irony-appreciation problem.

Schizophrenia and monothematic delusions

Numerous delusions have been studied which are highly specific and which can present in isolation in people whose beliefs are otherwise entirely unremarkable - "monothematic delusions" such as Capgras or Cotard delusions. We review such delusions and summarize our 2-factor theory of delusional belief which seeks to explain what causes these delusional beliefs to arise initially and what prevents them being rejected after they have arisen. Although these delusions can occur in the absence of other symptoms, they can also occur in the context of schizophrenia, when they are likely to be accompanied by other delusions and hallucinations. We propose that the 2-factor account of particular delusions like Capgras and Cotard still applies even when these delusions occur in the context of schizophrenia rather than occurring in isolation.

Need for closure, jumping to conclusions, and decisiveness in delusion-prone individuals

Need for closure refers to a motivated need for certainty. Jumping-to-conclusions bias refers to the gathering of minimal data when making overconfident probabilistic judgments. Both constructs have been associated independently with delusion-proneness. Fifty-eight nonclinical adults were assessed for jumping-to-conclusions bias using an experimental reasoning task, and need for closure, decisiveness concerning real-life dilemmas, and delusion-proneness using questionnaires. Delusion-proneness was associated independently with need for closure and jumping-to-conclusions bias, with no evidence of a direct relationship between the latter two. These results discount the view that need for closure motivates a jumping-to-conclusions bias, leading, in turn, to delusion-proneness. The various facets of need for closure proved to be independent; while intolerance of ambiguity correlated positively with delusion-proneness, decisiveness correlated negatively. The finding that delusion-prone individuals are more indecisive in everyday life was replicated using different scales. Delusion-proneness is associated independently with jumping-to-conclusions bias on experimental reasoning tasks, intolerance of ambiguity, and indecision concerning real-life dilemmas.

Taking the perspective of the other contributes to awareness of illness in schizophrenia

Two approaches dominate research on the lack of awareness of illness that characterizes schizophrenia. The "deficit" approach uses standardized neuropsychological batteries to identify the neural underpinnings of intact insight; the "nondeficit" approach investigates the psychological defense mechanisms that motivate denial of illness. We adopt, instead, a cognitive neuropsychological approach to model the cognitive processes which underpin insight and which might be either damaged (because of neuropathology) or not used (because of motivational forces). We conceive of these processes in terms of a metacognitive capacity "to see ourselves as others see us." We predict that a general difficulty with adopting other mental perspectives (with "seeing the world as others do"), indexed by performance deficits on theory of mind (ToM) tasks, will impair insight in schizophrenia. Thirty schizophrenic patients (also assessed for insight) and 26 healthy controls completed a battery of ToM tasks which varied presentation modality, response mode and instruction type (picture sequencing, joke appreciation and story comprehension tasks). While patients performed more poorly than controls on all ToM tasks, impairment in patients was not concordant across tasks. ToM scores from the picture sequencing and joke appreciation tasks, and not the story comprehension task, intercorrelated significantly in patients and predicted insight. Findings support the view that insight relies upon a cognitive capacity to adopt the other perspective, which, if intact, contributes to the metacognitive capacity to reflect upon "one's own" mental health from the other perspective. Findings also suggest that the nature of perspective-taking difficulty which disrupts insight in schizophrenia is best revealed using ToM tasks with "indirect" instructions.

Paranoia, persecutory delusions and attributional biases

An influential model of persecutory delusions put forward by Bentall and colleagues hypothesizes that persecutory-deluded patients avoid the activation of negative self-beliefs by making externalising, personalising attributions for negative events. The first study reported here used a new instrument for the measurement of persecutory ideation, the Paranoid, Persecutory and Delusion-Proneness Questionnaire, to investigate whether attributional biases are associated with subclinical persecutory ideation. The second study extended this investigation by re-examining associations between attributional biases and persecutory delusions. Both studies used the Internal, Personal and Situational Attributions Questionnaire to measure attributional style. No evidence was found for a connection between attributional biases and subclinical persecutory ideation. Furthermore, there was no support for an association between persecutory delusions and an externalising bias, and only marginal support for the hypothesized relationship between persecutory delusions and a personalising bias. These results suggest that the putative link between persecutory ideation and attributional biases only manifests (if at all) when persecutory ideation is of delusional intensity, and that it is confined to a personalising bias.

Externalizing and personalizing biases in persecutory delusions: The relationship with poor insight and theory-of-mind

The presence of externalizing bias (EB) for negative events together with personalizing bias (PB) (a bias to blame others rather than circumstances) may jointly constitute a vulnerability to develop persecutory delusions (PDs). Whereas EB purportedly serves to defend a vulnerable self-concept by avoiding negative self-attributions and might therefore exacerbate poor insight, PB may reflect cognitive deficits, including theory-of-mind impairment. We investigated these proposals in 34 schizophrenic patients with a history of PDs and 21 healthy controls. Patients with moderate- to severe-PDs and patients without a current PD showed excessive EB which was, surprisingly, absent in patients with mild persecutory delusions (mild-PDs). That EB might wax and wane with fluctuating delusional intensity was interpreted in accord with a new dynamic model of attribution self-representation cycles. As predicted, EB exacerbated poor insight. However, counter to predictions, theory-of-mind impairment did not increase PB, which was marked in all participants, whether clinical or non-clinical; instead, theory-of-mind impairment was also correlated with poor insight. Our findings indicate multiple pathways to poor insight, one of which is a theory-of-mind difficulty, impairing the capacity to simulate other perspectives for the purpose of critically evaluating one's own beliefs and circumstances.

Schizophrenia, theory of mind, and persecutory delusions

INTRODUCTION

There is already a substantial body of evidence supporting Frith's (1992) theory that theory of mind (ToM) is impaired in people with schizophrenia. However, a specific relationship between impaired ToM and paranoid delusions, while intuitively reasonable, has only been demonstrated in two studies to date.

METHODS

A total of 25 participants with schizophrenia were classified as paranoid or nonparanoid and compared with 38 healthy controls on a variety of ToM tasks. These tasks included verbal and nonverbal, and first and second order ToM tasks.

RESULTS

Participants with schizophrenia performed significantly more poorly than healthy controls on both the first and second order verbal ToM tasks but not on the nonverbal ToM tasks. However, the ToM deficit was only observed for those participants with schizophrenia who had persecutory delusions. There was also a strong relationship observed between the severity of persecutory delusions and length of illness.

CONCLUSIONS

This study represents only the third demonstration of a specific link between paranoid delusions and ToM impairment. Reasons why previous findings on this issue have been so inconsistent are considered. Further research is needed to explore the relationships among paranoia, ToM, and length of illness.

An experimental investigation of mentalization ability in borderline personality disorder

OBJECTIVE

Deficits in mentalization ability have been theorized to underlie borderline personality disorder (BPD) and have led to mentalization-based treatments. Yet there has been little empirical investigation into whether mentalization deficits do differentiate the BPD population from healthy controls, and the specific nature of these differences.

METHOD

Five pre-existing Theory of Mind (ToM) tasks that assessed simple to complex mentalization capacity in both the affective and cognitive domains were administered to the same groups of age and gender matched patients with BPD and controls. Self-report measures assessed cognitive and affective empathy and childhood trauma and abuse.

RESULTS

The BPD group did not differ significantly from the healthy control group on basic cognitive false-belief picture-sequencing tasks, or on overall accuracy when discriminating mental states from viewing images of eyes, and attributing emotions based on social events. They were, however, significantly less accurate in identifying positive mental states on the Reading the Mind in the Eyes (RME) task and showed significantly more mentalization errors on affective and cognitive understanding of faux pas (faux pas total score p<.01) and on a Joke Appreciation task (p=.01), that required integration of multiple perspectives. They also self-reported less empathic perspective taking (p<.01). Observation of patterns of performance hinted at specific underlying biases (e.g. a default tendency to use superficial black-and-white attributions to others, such as, "he is mean", when explaining behavior). It was also found that as childhood experiences of punishment increased, adulthood mentalization ability decreased on all affective ToM tasks and on the cognitive and affective components of understanding faux pas.

CONCLUSIONS

The BPD group was as capable as controls in undertaking simple mentalization. However, deficits in mentalization capacity became evident when mentalization tasks became more complex and required the integration of multiple perspectives. Increasing childhood experiences of punishment were related to decreasing mentalization ability in adulthood. Findings support the use of treatments to improve mentalization skills in BPD, however, further research is needed to better specify the nature of underlying mentalizing biases in this population.