Verbal fluency impairments among middle-aged and older outpatients with schizophrenia are characterized by deficient switching

What Drives Animal Fluency Performance in Cantonese-Speaking Chinese Patients with Adult-Onset Psychosis?

Among the numerous studies investigating semantic factors associated with functioning in psychotic patients, most have been conducted on western populations. By contrast, the current cross-sectional study involved native Cantonese-speaking Chinese participants. Using the category fluency task, we compared performance between patients and healthy participants and examined clinical and sociodemographic correlates. First-episode psychosis patients (n = 356) and gender- and age-matched healthy participants (n = 35) were asked to generate as many ‘animals’ as they could in a minute. As expected, patients generated fewer correct responses (an average of 15.5 vs. 22.9 words), generated fewer clusters (an average of 3.7 vs. 5.4 thematically grouped nouns), switched less between clusters (on average 8.0 vs. 11.9 switches) and, interestingly, produced a larger percentage of Chinese zodiac animals than healthy participants (an average of 37.7 vs. 24.2). However, these significant group differences in the clusters and switches disappeared when the overall word production was controlled for. Within patients, education was the strongest predictor of category fluency performance (namely the number of correct responses, clusters, and switches). The findings suggest that an overall slowness in patients may account for the group differences in category fluency performance rather than any specific abnormality per se.

Atypical frontotemporal cortical activity in first-episode adolescent-onset schizophrenia during verbal fluency task: A functional near-infrared spectroscopy study

Background

Frontotemporal cortex dysfunction has been found to be associated with cognitive impairment in patients with schizophrenia (SCZ). In patients with adolescent-onset SCZ, a more serious type of SCZ with poorer functional outcome, cognitive impairment appeared to occur at an early stage of the disease. However, the characteristics of frontotemporal cortex involvement in adolescent patients with cognitive impairment are still unclear. In the present study, we aimed to illustrate the frontotemporal hemodynamic response during a cognitive task in adolescents with first-episode SCZ.

Methods

Adolescents with first-episode SCZ who were aged 12-17 and demographically matched healthy controls (HCs) were recruited. We used a 48-channel functional near-infrared spectroscopy (fNIRS) system to record the concentration of oxygenated hemoglobin (oxy-Hb) in the participants' frontotemporal area during a verbal fluency task (VFT) and analyzed its correlation with clinical characteristics.

Results

Data from 36 adolescents with SCZ and 38 HCs were included in the analyses. Significant differences were found between patients with SCZ and HCs in 24 channels, mainly covering the dorsolateral prefrontal cortex, superior and middle temporal gyrus and frontopolar area. Adolescents with SCZ showed no increase of oxy-Hb concentration in most channels, while the VFT performance was comparable between the two groups. In SCZ, the intensity of activation was not associated with the severity of symptoms. Finally, receiver operating characteristic analysis indicated that the changes in oxy-Hb concentration could help distinguish the two groups.

Conclusion

Adolescents with first-episode SCZ showed atypical cortical activity in the frontotemporal area during the VFT, and fNIRS features might be more sensitive indicators in cognitive assessment, indicating that the characteristic hemodynamic response pattern might be potential imaging biomarkers for this population.

Semantic fluency reveals reduced functional connectivity between subcategorical co-hyponyms in recent-onset inpatients with first-episode psychosis

Data on clustering and switching during semantic fluency (SF) in patients with first-episode psychosis (PwFEP) are scant. We aimed to investigate (1) clustering and switching on SF in PwFEP using more detailed clustering analyses and (2) the possibility of disproportionate clustering deficits across different SF tasks in PwFEP and healthy subjects (HS), with the latter being suggested by the current literature on patients with schizophrenia. We recruited 22 Croatian-speaking PwFEP with schizophrenia features or symptoms and 22 HS matched in age, sex distribution, and handedness. All patients were medicated and had a mean illness duration of 1 month. The categories animals, trees, vegetables, fruits, and musical instruments were administered for SF. PwFEP produced significantly fewer correct words in the aggregate score, as well as across all categories. The switching rate was significantly higher in PwFEP, but no post hoc comparisons were significant. PwFEP also produced significantly smaller clusters, yet the post hoc comparisons for the tree and fruit task were not significant. A higher switching rate and smaller clusters indicate less efficient functional connectivity within subcategories of the given categories, but not necessarily between the subcategories. Although both less likely to produce a cluster once a switch has been uttered and less likely to produce clusters larger than two words compared to HS, the latter deficit was more pronounced. Our results further suggest that PwFEP might show normal clustering performance on some SF tasks. We discuss the results in the context of the hypothesis of semantic hyperactivation in psychoses.

Semantic and phonetic similarity of verbal fluency responses in early-stage psychosis

Linguistic abnormalities can emerge early in the course of psychotic illness. Computational tools that quantify similarity of responses in standardized language-based tasks such as the verbal fluency test could efficiently characterize the nature and functional correlates of these disturbances. Participants with early-stage psychosis (n=20) and demographically matched controls without a psychiatric diagnosis (n=20) performed category and letter verbal fluency. Semantic similarity was measured via predicted context co-occurrence in a large text corpus using Word2Vec. Phonetic similarity was measured via edit distance using the VFClust tool. Responses were designated as clusters (related items) or switches (transitions to less related items) using similarity-based thresholds. Results revealed that participants with early-stage psychosis compared to controls had lower fluency scores, lower cluster-related semantic similarity, and fewer switches; mean cluster size and phonetic similarity did not differ by group. Lower fluency semantic similarity was correlated with greater speech disorganization (Communication Disturbances Index), although more strongly in controls, and correlated with poorer social functioning (Global Functioning: Social), primarily in the psychosis group. Findings suggest that search for semantically related words may be impaired soon after psychosis onset. Future work is warranted to investigate the impact of language disturbances on social functioning over the course of psychotic illness.

Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration

Impairments in category verbal fluency task (VFT) performance have been widely documented in psychosis. These deficits may be due to disturbed “cognitive foraging” in semantic space, in terms of altered salience of cues that influence individuals to search locally within a subcategory of semantically related responses (“clustering”) or globally between subcategories (“switching”). To test this, we conducted a study in which individuals with schizophrenia (n = 21), schizotypal personality traits (n = 25), and healthy controls (n = 40) performed VFT with “animals” as the category. Distributional semantic model Word2Vec computed cosine-based similarities between words according to their statistical usage in a large text corpus. We then applied a validated foraging-based search model to these similarity values to obtain salience indices of frequency-based global search cues and similarity-based local cues. Analyses examined whether diagnosis predicted VFT performance, search strategies, cue salience, and the time taken to switch between vs search within clusters. Compared to control and schizotypal groups, individuals with schizophrenia produced fewer words, switched less, and exhibited higher global cue salience, indicating a selection of more common words when switching to new clusters. Global cue salience negatively associated with vocabulary ability in controls and processing speed in schizophrenia. Lastly, individuals with schizophrenia took a similar amount of time to switch to new clusters compared to control and schizotypal groups but took longer to transition between words within clusters. Findings of altered local exploitation and global exploration through semantic memory provide preliminary evidence of aberrant cognitive foraging in schizophrenia.

Influence of age and education on the processing of clustering and switching in verbal fluency tasks

Verbal fluency (VF) is a widely used tool in neuropsychological assessment.

OBJECTIVE

We aimed to investigate the influence of age and educational level on clustering and switching in three VF modalities: phonemic (PVF), semantic (SVF) and unconstrained (UVF). We evaluated type of cluster, mean cluster size, and quantity of clusters, intersections, and returns. A total of 260 healthy subjects were assessed.

METHODS

Participants were divided into three age groups: young adults (18 to 39 years), middle-aged adults (40 to 59 years) and older adults (60 to 80 years) and into two groups of educational level: 1-8 years (low), 9 years or more (high). A two-way ANOVA analysis was conducted to analyze the effect of age and educational level and its interactions. A repeated measures ANOVA was performed to verify the performance during the task.

RESULTS

A main effect of age was detected on the UVF and SVF scores for total switches, taxonomic clusters, and for the total semantic clusters on the SVF. There was a greater effect of educational level on total switches (UVF, PFV and SVF), taxonomic clusters (UVF and SVF), thematic clusters and total semantic cluster (UVF), phonemic and mixed clusters (PVF), mean cluster size (UVF and SVF) and intersections (SVF). Educational level had a greater effect on all three VF tasks.

Ineffective initiation contributes to deficient verbal and non-verbal fluency in patients with schizophrenia

AIMS

Patients with schizophrenia (SCH) show impaired verbal and non-verbal fluency. However, these individuals' fluctuations in words or designs generation efficiency over time, a phenomenon that may significantly affect fluency, have never been studied. Thus, the aim of this research was to investigate if individuals with SCH may present with alternations in the dynamics of the information production and its control as well as to test if the potential abnormalities in this regard might affect these patients' overall performance on both verbal and non-verbal fluency tasks.

METHOD

Forty-four patients with SCH and 40 healthy controls (HC) completed both verbal (phonological, semantic) and non-verbal fluency tests. To analyse processing efficiency changes over time, the period in which subjects had to generate words or designs (60 s) has been divided into 15-s sections.

RESULTS

In comparison to HCs, individuals with SCH obtained significantly lower total scores for all fluency measures. Furthermore, group differences in the dynamics of the test performance also emerged, with SCH patients having a significantly worse production during the initial 15 s of each fluency task. Additionally, the initial production deficiency seen in patients with SCH has accounted for these individuals' total performance. Moreover, comparisons of errors distribution over time during the phonemic and figural fluency performance also revealed differences, suggesting there was a rapid depletion in maintaining of cognitive control in the SCH sample.

CONCLUSIONS

Inefficient fluency in SCH may arise from a more general initiation deficits that may partly account for these patients' cognitive problems.

Chinese character fluency test: an investigation of psychometric properties

OBJECTIVE

Verbal fluency test (VFT), one of the most commonly used tests to evaluate executive function (EF), can be subdivided into letter fluency (LF) and semantic fluency (SF). Although SF tasks have been established in Eastern societies, it is difficult to develop a LF task (Non-SF task) in Mandarin. This study thus aims to examine the psychometric properties of the Chang Gung University Orthographical Fluency Test (CGUOFT), a non-SF task with Chinese characters.

METHOD

A total of 290 participants were recruited from the community. Thirty participants were retested for the test-retest reliability. Three tests of EFs were used for the criterion-related validity.

RESULTS

CGUOFT has fair internal consistency and good test-retest reliability. The concurrent validity of CGUOFT is also acceptable. An exploratory factor analysis showed a one-factor structure, and the CGUOFT scores significantly correlated with sex, age and educational level.

CONCLUSIONS

This study might be the first one considering the Chinese characters to establish a VFT. Based on good psychometric properties, it merits evaluations of the CGUOFT from clinical samples in future studies.

Verbal fluency, clustering, and switching in patients with psychosis following traumatic brain injury (PFTBI)

Verbal fluency in patients with psychosis following traumatic brain injury (PFTBI) has been reported as comparable to healthy participants. This finding is counterintuitive given the prominent fluency impairments demonstrated post-traumatic brain injury (TBI) and in psychotic disorders, e.g. schizophrenia. We investigated phonemic (executive) fluency (3 letters: 'F' 'A' and 'S'), and semantic fluency (1 category: fruits and/or vegetables) in four matched groups; PFTBI (N=10), TBI (N=10), schizophrenia (N=23), and healthy controls (N=23). Words produced (minus perseverations and errors), and clustering and switching scores were compared for the two fluency types across the groups. The results confirmed that PFTBI patients do show impaired fluency, aligned with existing evidence in TBI and schizophrenia. PFTBI patients produced the least amount of words on the phonemic fluency ('A') trial and total score, and demonstrated reduced switching on both phonemic and semantic tasks. No significant differences in clustering performance were found. Importantly, the pattern of results suggested that PFTBI patients share deficits with their brain-injured (primarily executive), and psychotic (executive and semantic), counterparts, and that these are exacerbated by their dual-diagnosis. These findings add to a very limited literature by providing novel evidence of the nature of fluency impairments in dually-diagnosed PFTBI.

Do the letters F, A and S represent Indonesian letter fluency stimuli?

INTRODUCTION

The letters F, A and S, originally used in the English letter fluency stimuli test, have been frequently adopted to assess executive function in many languages. However, few studies reported the significance of FAS testing employed in different languages. The current study explored whether FAS could be widely applied to the Indonesian language.

METHODS

A total of 211 undergraduate students from state and private universities who participated in this study were randomly assigned into four groups. Each group was exposed to six different letter fluency stimuli. The total number of words the participants produced for each letter stimulus were averaged and ranked to determine the degree of difficulty in generating words. Furthermore, the normal distribution and equal ratio comparison were examined to verify the representative letter fluency stimuli. In addition, the effect of sex and university affiliation on letter fluency performance was also analyzed.

RESULTS

The letters A and S were among the easiest letters used to generate words; however, the letter F was regarded as a difficult stimulus. Furthermore, only the number of words beginning the letter S was distributed according to a normal curve. The number of words starting with the letters F and A were not normally distributed. Although sex difference was not associated with letter fluency performance, difference in university affiliation showed a significant effect on performance.

DISCUSSION

Our findings suggest that consideration of several stimuli factors is required to accurately measure performance in the letter fluency task in a specific language.

Neuropsychological characteristics of verbal and non-verbal fluency in schizophrenia patients

This review paper provides analyses confirming correlation between various brain regions activity, particularly its prefrontal portions, and schizophrenia patients' performance in verbal fluency tests. Various factors modifying patients' performance in the aforementioned tasks were singled out and discussed. Systematically we have reviewed the results of non-verbal fluency tests conducted in the schizophrenic patients. The authors also summarizes findings of earlier studies stressing the role of semantic fluency as a predictor of first-episode psychosis. Verbal and non-verbal fluency tests engage complex cognitive processes and executive functions in patients. As a result, the interpretation of their results is often complicated and requires special competences. The tests are popular neuropsychological tools used for assessment of verbal memory, executive functions, visual-spatial abilities and psychomotor speed in patients with mental and neurological disorders. The aim of this paper is to discuss diagnostic tools used for measuring both types of fluency (verbal and non-verbal), test interpretation methods, as well as their usefulness in clinical diagnostics and scientific research.

Language-dependent performance on the letter fluency task in patients with schizophrenia

Two types of verbal fluency tasks (letter fluency task; LFT, category fluency task; CFT) have been widely used to assess cognitive function in people with psychiatric diseases including schizophrenia. The task demand of the LFT is considered to vary across languages, as the cognitive process largely relies on sound and writing systems. Specifically, a sound unit for a letter (s) and a manner of association between them are assumed to be related with the performance. In the current study, three analyses have been conducted to examine this issue, using Japanese, Turkish, and English-speaking patients with schizophrenia. It was hypothesized that severity of letter fluency impairment would be in the order of Japanese, Turkish, and English speaking patients according to the inflexibility of a word search. First, performance on the LFT and the CFT was compared among Japanese (N=40), Turkish (N=30), and the US (N=31) patients (Analysis 1). A significant difference was found between the US and other two groups only in the LFT. Second, verbal fluency performance was compared between Japanese and Turkish patients by contrasting the degree of disassociations from normal controls (Japanese: N=20, Turkish: N=30) (Analysis 2). In Japanese patients, performance on the LFT was more severely impaired compared to that on the CFT while the opposite trend was found in the Turkish counterpart, suggesting that letter fluency performance was more degraded in Japanese patients. Finally, Analysis 3 was conducted to examine the relative order of letter fluency impairment among Japanese, Turkish and English-speaking patients. Disassociation in English users with schizophrenia was estimated based on previous meta-analytic reviews. The effect size (ES) for the letter fluency deficit was the largest in the Japanese sample, while the other two groups share similar ESs. The results from the three analyses partially supported the hypothesis for the severity of the letter fluency impairment in patients with schizophrenia. The language-dependency of letter fluency impairment was thought to be explained by the theoretical model built on unique properties of sound and writing systems. The considerations presented here would provide useful information for optimizing the portability of cognitive tasks across languages.

Component analysis of verbal fluency scores in severe traumatic brain injury

PRIMARY OBJECTIVE

This study set out to examine the sensitivity of verbal fluency component scores in severe traumatic brain injury (TBI).

RESEARCH DESIGN

A retrospective cross-sectional design was used, with control participants chosen at random from the community and TBI patients from litigation cases.

METHODS AND PROCEDURES

Fifty-four healthy controls and 28 patients who had incurred a severe TBI were included in the study. The Controlled Oral Word Association test was rescored to include clustering and switching scores for phonemic and semantic fluency separately. The scores were compared between controls and TBI patients using independent samples t-tests.

MAIN OUTCOMES AND RESULTS

The findings demonstrate that component scores for semantic fluency yielded the largest effect sizes overall (d = 1.32 and d = 1.53), but not phonemic fluency. Total words generated in phonemic fluency yielded the largest effect size, although still modest (d = 0.62).

CONCLUSIONS

While verbal fluency may be a useful test tool to elicit evidence of neuropsychological impairment after TBI, these findings are consistent with previous research demonstrating that component scores are more sensitive indices. There is potential clinical utility in using component scores for examining the specific severity of verbal fluency impairment in TBI and guiding rehabilitation efforts.

Component analysis of verbal fluency in patients with mild traumatic brain injury

We set out to examine the sensitivity of switching and clustering component scores of verbal fluency in patients with mild traumatic brain injury (mTBI). Clustering and switching scores were compared between patients with mTBI and healthy normal controls as well as those with moderate TBI and severe TBI. Fifty-four healthy controls along with 20 mild TBI, 8 moderate TBI, and 12 severe TBI patients were included in the study. Our findings demonstrate that component score effect sizes were larger than those of total words generated for both phonemic and semantic fluency. This pattern of finding held true regardless of comparison group. In addition, semantic fluency component scores were found to correspond to larger component score effect sizes than did phonemic fluency component scores. Our findings demonstrate that component scores derived from the Controlled Oral Word Association Test may be sufficient to reliably capture the effects of unremitting injury (i.e., more than 3 months post status) to the frontal and temporal brain as evinced in cases of unremitting mTBI. This differential pattern of performance provides preliminary evidence for the potential usefulness of switching and clustering in the assessment of mTBI. Given the small sample sizes employed in our study, however, future studies are needed to determine whether component measures of verbal fluency have discriminative ability.

Choosing our words: retrieval and selection processes recruit shared neural substrates in left ventrolateral prefrontal cortex

When we speak, we constantly retrieve and select words for production in the face of multiple possible alternatives. Our ability to respond in such underdetermined situations is supported by left ventrolateral prefrontal cortical (VLPFC) regions, but there is active debate about whether these regions support (1) selection between competing alternatives, (2) controlled retrieval from semantic memory, or (3) selection and controlled retrieval in distinct subregions of VLPFC (selection in mid-VLPFC and controlled retrieval in anterior VLPFC). Each of these theories has been supported by some prior evidence but challenged by other findings, leaving the debate unresolved. We propose that these discrepancies in the previous literature reflect problems in the way that selection and controlled retrieval processes have been operationalized and measured. Using improved measures, we find that shared neural substrates in left VLPFC support both selection and controlled retrieval, with no dissociation between mid and anterior regions. Moreover, selection and retrieval demands interact in left VLPFC, such that selection effects are greatest when retrieval demands are low, consistent with prior behavioral findings. These findings enable a synthesis and reinterpretation of prior evidence and suggest that the ability to respond in underdetermined situations is affected by both selection and retrieval mechanisms for verbal material subserved by left VLPFC, and these processes interact in meaningful ways.

Evaluation of specific executive functioning skills and the processes underlying executive control in schizophrenia

Schizophrenia is associated with executive dysfunction. Yet, the degree to which executive functions are impaired differentially, or above and beyond underlying basic cognitive processes is less clear. Participants included 145 matched pairs of individuals with schizophrenia (SCs) and normal comparison subjects (NCs). Executive functions were assessed with 10 tasks of the Delis-Kaplan Executive Function System (D-KEFS), in terms of "achievement scores" reflecting overall performance on the task. Five of these tasks (all measuring executive control) were further examined in terms of their basic component (e.g., processing speed) scores and contrast scores (reflecting residual higher order skills adjusted for basic component skills). Group differences were examined via multivariate analysis of variance. SCs had worse performance than NCs on all achievement scores, but the greatest SC-NC difference was that for the Trails Switching task. SCs also had worse performance than NCs on all basic component skills. Of the executive control tasks, only Trails Switching continued to be impaired after accounting for impairments in underlying basic component skills. Much of the impairment in executive functions in schizophrenia may reflect the underlying component skills rather than higher-order functions. However, the results from one task suggest that there might be additional impairment in some aspects of executive control.

Ethics in Psychiatric Research: A Review of 25 Years of NIH-funded Empirical Research Projects

BACKGROUND: This paper reviews the past 25 years of empirical research funded by the National Institutes of Health (NIH) on matters of ethics in psychiatric research. METHODS: Using the NIH RePORTER and Medline databases, we identified 43 grants and 77 publications that involved the empirical study of a matter of ethics in research involving mental health service users. RESULTS: These articles provide original and useful information on important topics, most especially the capacity to consent and the voluntariness of consent. For example, participants who share a diagnosis vary widely in levels of cognitive impairment that correlate with decisional capacity, and capacity to consent can be enhanced easily using iterative consent processes. Few articles address matters of justice or benefits in research, particularly from the perspectives of participants. No articles address matters of privacy, confidentiality, or researcher professionalism. CONCLUSIONS: Despite the usefulness of data from the studies conducted to date, current research on research ethics in psychiatry does not adequately address the concerns of service users as expressed in recent publications.

Action and object naming in schizophrenia

Patients with schizophrenia demonstrate impaired action verbal fluency, but no study has examined verb-noun differences using picture naming. The present study compared object and action naming in 20 adult patients diagnosed with schizophrenia (DSM-IV-TR, Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, Text Revision; American Psychiatric Association, 2000) criteria, and 20 demographically matched healthy controls, using pictures. Overall, schizophrenic patients showed poorer naming than controls on all measures of object and action lexical semantic access and retrieval despite normal comprehension for action and object names. Results further indicated that action names were significantly more difficult to retrieve than object names in schizophrenic patients. The absence of dissociation in comprehension of action and object names but semantic errors in naming both classes suggests intact conceptual-semantic stores among middle-aged community-dwelling outpatients with schizophrenia but difficulties mapping semantics onto the lexicon. Action-naming impairments can arise from both semantic and postsemantic origins in schizophrenia. These results have implications for the neurobiology of language given the association between both schizophrenia and verb processing and frontal damage. Moreover, the issue being addressed is important for a cognitive characterization of schizophrenia and for an understanding of the representations of action and object names in the brain.

Prevalence and longitudinal stability of negative symptoms in healthy participants

OBJECTIVE

Although negative symptoms are prominent in older patients with schizophrenia, it is unknown whether this pattern is prevalent in healthy participants. The objective of this study was to evaluate whether negative symptoms are present in healthy populations and to determine whether they are linked to illness-related processes or normal aging.

METHODS

A systemic review of 26 studies that have administered negative symptom assessments to healthy participants was conducted. In addition, 213 (age > 40 years old) healthy participants completed PANSS and SANS ratings at both baseline and 1-year follow-up. One-hundred participants also completed ratings after 3 years.

RESULTS

Across all reviewed studies, negative symptoms were absent in the majority of participants. Comparable results were found in the current study's large longitudinal evaluation with middle-aged to older adults.

CONCLUSIONS

Taken together, the data suggest that healthy volunteers do not suffer from prominent negative symptoms. This finding is consistent with the hypothesis that the greater prevalence and severity of negative symptoms in older patients is not related to normal aging but to illness-related processes.

Symptoms as mediators of the relationship between neurocognition and functional outcome in schizophrenia: a meta-analysis

BACKGROUND

Neurocognitive functioning in schizophrenia has received considerable attention because of its robust prediction of functional outcome. Psychiatric symptoms, in particular negative symptoms, have also been shown to predict functional outcome, but have garnered much less attention. The high degree of intercorrelation among all of these variables leaves unclear whether neurocognition has a direct effect on functional outcome or whether that relationship to functional outcome is partially mediated by symptoms.

METHODS

A meta-analysis of 73 published English language studies (total n=6519) was conducted to determine the magnitude of the relationship between neurocognition and symptoms, and between symptoms and functional outcome. A model was tested in which symptoms mediate the relationship between neurocognition and functional outcome. Functional outcome involved measures of social relationships, school and work functioning, and laboratory assessments of social skill.

RESULTS

Although negative symptoms were found to be significantly related to neurocognitive functioning (p<.01) positive symptoms were not (p=.97). The relationship was moderate for negative symptoms (r=-.24, n=4757, 53 studies), but positive symptoms were not at all related to neurocogniton (r=.00, n=1297, 25 studies). Negative symptoms were significantly correlated with functional outcome (r=-.42, p<.01), and again the correlation was higher than for positive symptoms (r=-.03, p=.55). Furthermore, our findings support a model in which negative symptoms significantly mediate the relationship between neurocognition and functional outcome (Sobel test p<.01).

CONCLUSIONS

Although neurocognition and negative symptoms are both predictors of functional outcome, negative symptoms might at least partially mediate the relationship between neurocognition and outcome.

Impact of coexistent schizotypal personality traits on frontal lobe function in obsessive-compulsive disorder

OBJECTIVE

This study was a post-hoc analysis of the results from a neuropsychological battery which was conducted to investigate the frontal lobe difference between obsessive-compulsive disorder (OCD) patients with and without schizotypal personality trait (SPT), especially dorsolateral prefrontal and medial frontal functions.

METHODS

Fifty-five OCD patients were divided into two groups according to their Personality Disorder Questionnaire-4+ scores. Patients with OCD with SPT (n=17) and OCD without SPT (n=38) were compared to 52 schizophrenia patients and 67 healthy subjects. Two neuropsychological tasks, the Wisconsin Card Sorting Test (WCST) and verbal fluency tests which are considered to reflect dorsolateral and medial frontal functions, were selected for an analysis.

RESULTS

OCD with SPT patients and patients with schizophrenia performed significantly worse than controls in both the WCST and verbal fluency tasks, whereas OCD without SPT patients showed no deficits in the same tasks. Moreover, we found no statistically significant difference in either task between patients having OCD with SPT and patients with schizophrenia.

CONCLUSION

This study indicate that OCD with SPT may have distinct patterns of neurocognitive deficit that differ from those of OCD without SPT, especially in terms of frontal lobe function.