The prevalence, incidence, and admission rate of diagnosed schizophrenia spectrum disorders in Korea, 2008-2017: A nationwide population-based study using claims big data analysis

This study estimated the prevalence and incidence rate of schizophrenia, schizotypal, and delusional disorders (SSDD) in Korea from 2008 to 2017 and analyzed the hospital admission rate, re-admission rate, and hospitalization period. It used the Korean nationwide National Health Insurance Service claims database. SSDD patients who had at least one visit to Korea's primary, secondary, or tertiary referral hospitals with a diagnosis of SSDD, according to the International Classification of Diseases, 10th Revision (ICD-10), were identified as SSDD cases if coded as F20-F29. Data were analyzed using frequency statistics. Results showed that the 12-month prevalence rate of SSDD increased steadily from 0.40% in 2008 to 0.45% in 2017. Analysis of the three-year cumulative prevalence rate of SSDD showed an increase from 0.51% in 2011 to 0.54% in 2017. In 2017, the five-year cumulative prevalence rate was 0.61%, and the 10-year cumulative prevalence rate was 0.75%. The hospital admission rate among SSDD patients decreased from 2008 (30.04%) to 2017 (28.53%). The incidence of SSDD was 0.05% and no yearly change was observed. The proportion of SSDD inpatients whose first hospital visit resulted in immediate hospitalization was 22.4% in 2017. Epidemiological indicators such as prevalence, incidence, and hospitalization rate play an important role in planning social and financial resource allocation. Therefore, efforts to produce more accurate epidemiological indicators are very important and this study's findings could have a significant social impact.

Has "Iron" Felix Dzerzhinsky been affected by post-traumatic embitterment disorders?

Retrospective psycho-historical personality analysis of "Iron" Felix Dzerzhinsky presents an opportunity to evaluate development and progression of events and behaviors associated with the killing of hundreds of thousands during the "Red Terror". A biopsychosocial assessment provides evidence suggestive of the presence of post-traumatic embitterment disorder (PTED) as an underlying pathological catalyst for his actions. The introduction of PTED as a possible psychopathology leading to such violent and destructive events promotes the significance of understanding the diagnosis and how negative events may lead to maladaptive behaviors on a broad scale.

Aberrant myelination of the cingulum and Schneiderian delusions in schizophrenia: a 7T magnetization transfer study

BACKGROUND

The structural integrity of the anterior cingulum has been repeatedly observed to be abnormal in patients with schizophrenia. More recently, aberrant myelination of frontal fasciculi, especially, cingulum has been proposed to underlie delayed corollary discharges that can affect sense of agency and contribute to delusions of control (Schneiderian delusions). Using the magnetization transfer phenomenon at an ultra-high field 7T MRI, we investigated the putative myelin content of cingulum bundle in patients with schizophrenia.

METHODS

Seventeen clinically stable patients with schizophrenia and 20 controls were recruited for this 7T MRI study. We used a region-of-interest method and extracted magnetization transfer ratio (MTR) from left and right dorsal cingulum bundles and estimated patients v. controls differences. We also related the cingulum MTR values to the severity of Schneiderian delusions.

RESULTS

Patients had a significant reduction in the MTR, indicating reduced myelin content, in the cingulum bundle (right cingulum Hedges' g = 0.91; left cingulum g = 0.03). The reduced MTR of left cingulum was associated with higher severity of Schneiderian delusions (τ = -0.45, p = 0.026) but no such relationship was seen for the right cingulum MTR (τ = -0.136, p = 0.50) among patients. The association between the left cingulum MTR and Schneiderian delusions was not explained by the presence of other delusions, hallucinations, disorganization or negative symptoms.

CONCLUSIONS

Dysmyelination of the cingulum bundle is seen in a subgroup of patients with schizophrenia and may be involved in the mechanism of Schneiderian delusions.

Altered corticostriatal pathway in first-episode paranoid schizophrenia: Resting-state functional and causal connectivity analyses

Neuroimaging studies suggest the abnormal structure and function of basal ganglion may contribute to the pathophysiology of schizophrenia. However, little is investigated about the both aberrant functional and causal connectivity of striatum in first-episode paranoid schizophrenia (FEPS). Resting-state functional magnetic resonance imaging was used to characterize the functional connectivity (FC) and casual connectivity within the corticostriatal circuit in 31 patients with FEPS and 33 healthy controls. Degree centrality (DC) was used to explore the regions influenced in schizophrenia at the whole-brain level. Subsequently, a seed-based Granger causality analysis was performed to analyze the causal connectivity. We identified reduced DC of the bilateral putamen in the patients, compared to the controls. In the causal connectivity analysis, we found causal dysconnectivity between the putamen and several regions of default mode network, right orbital part of inferior frontal cortex and right fusiform in the patients. Further, the abnormal causal effect was associated with cognitive impairment in FEPS. The present study highlighted the abnormal functional and causal integrity of the striatum in the patients with FEPS during resting state and suggests a potentially implicated role for the cortical-striatal circuit, especially the striatal-default mode network loop, in the pathophysiology of schizophrenia.

Transdiagnostic deviant facial recognition for implicit negative emotion in autism and schizophrenia

Impaired facial affect recognition (FAR) is observed in schizophrenia and autism spectrum disorder (ASD) and has been linked to amygdala and fusiform gyrus dysfunction. ASD patient's impairments seem to be more pronounced during implicit rather than explicit FAR, whereas for schizophrenia data are inconsistent. However, there are no studies comparing both patient groups in an identical design. The aim of this three-group study was to identify (i) whether FAR alterations are equally present in both groups, (ii) whether they are present rather during implicit or explicit FAR, (iii) and whether they are conveyed by similar or disorder-specific neural mechanisms. Using fMRI, we investigated neural activation during explicit and implicit negative and neutral FAR in 33 young-adult individuals with ASD, 20 subjects with paranoid-schizophrenia and 25 IQ- and gender-matched controls individuals. Differences in activation patterns between each clinical group and controls, respectively were found exclusively for implicit FAR in amygdala and fusiform gyrus. In addition, the ASD group additionally showed reduced activations in medial prefrontal cortex (PFC), bilateral dorso-lateral PFC, ventro-lateral PFC, posterior-superior temporal sulcus and left temporo-parietal junction. Although subjects with ASD showed more widespread altered activation patterns, a direct comparison between both patient groups did not show disorder-specific deficits in neither patient group. In summary, our findings are consistent with a common neural deficit during implicit negative facial affect recognition in schizophrenia and autism spectrum disorders.

The impact of depressive symptoms on the clinical presentation of Persistent Delusional Disorder

BACKGROUND

Our aim was to investigate the influence of depressive symptoms on the clinical presentation of Persistent Delusional Disorder (PDD).

METHODS

We have previously conducted a retrospective review of patients diagnosed with PDD (n = 455). We divided this sample into two groups according to the presence or absence of co-morbid depressive symptoms - a subsample of PDD with depressive co-morbidity (PDD + D; n = 187) and a subsample of PDD without depressive co-morbidity (PDD only; n = 268).

RESULTS

PDD + D group had a significantly younger age at onset of PDD. The PDD + D group received significantly more antidepressants but had similar response and adherence rates.

CONCLUSIONS

The presence of depressive symptoms in 41% of the study population did not appear to influence the clinical presentation or response to treatment.

Day/night changes in serum S100B protein concentrations in acute paranoid schizophrenia

There are day/night and seasonal changes in biological markers such as melatonin and cortisol. Controversial changes in serum S100B protein levels have been described in schizophrenia. We aim studying whether serum S100B levels present day/night variations in schizophrenia patients and whether S100B levels are related to psychopathology. Sixty-five paranoid schizophrenic inpatients participated in the study. Psychopathology was assessed with the Positive and Negative Syndrome Scale (PANSS) at admission and discharge. Blood was drawn at 12:00 (midday) and 00:00 (midnight) hours at admission and discharge. Sixty-five healthy subjects matched by age, gender and season acted as control group. At admission and discharge patients had significantly higher serum S100B concentrations at midday and midnight than healthy subjects. At admission, patients showed a day/night variation of S100B levels, with higher S100B levels at 12:00 than at 00:00h (143.7±26.3pg/ml vs. 96.9±16.6pg/ml). This day/night difference was not present in the control group. Midday and midnight S100B at admission decreased when compared to S100B at discharge (midday, 143.7±26.3 vs. 83.0±12, midnight 96.9±16.6 vs. 68.6±14.5). There was a positive correlation between the PANSS positive subscale and S100B concentrations at admission. This correlation was not present at discharge.

CONCLUSIONS

acute paranoid schizophrenia inpatients present a day/night change of S100B serum levels at admission that disappears at discharge. The correlation between serum S100B concentrations and the PANSS positive scores at admission as well as the decrease of S100B at discharge may be interpreted as an acute biological response to the clinical state of the patients.

Delusional disorder and schizophrenia: a comparative study across multiple domains

BACKGROUND

Delusional disorder (DD) is an under-researched condition and its relationship to schizophrenia (SZ) controversial. This study aimed to further characterize DD and to examine multi-domain evidence for the distinction between DD and SZ.

METHOD

Using univariate analyses we examined 146 subjects with DD, 114 subjects with paranoid SZ and 244 subjects with non-paranoid SZ on 52 characteristics from several domains including demographics, risk factors, premorbid features, illness characteristics, index episode features, delusional-related features, response to treatment and outcome. In a further step, we searched for independent associations of the examined characteristics with DD v. SZ.

RESULTS

Univariate analyses showed that DD differed from either form of SZ in 40 characteristics, the pattern of findings indicated that paranoid SZ was much more similar to non-paranoid SZ than DD. Relative to subjects with SZ, those with DD were more likely to have drug abuse before illness onset, better premorbid sexual adjustment, later age at illness onset, higher levels of affective symptoms and lack of insight, poorer response to antipsychotic medication, better functioning in the domains of personal care, paid work and social functioning; last, subjects with DD had fewer but more severe delusions and higher ratings of conviction of delusional experience than those with SZ. Predominance of jealousy and somatic delusions was confined to subjects with DD.

CONCLUSIONS

DD and SZ represent two distinct classes of disorders, the differential features of DD being of nosological, aetiological and therapeutic relevance.

Prediction of transition from ultra-high risk to first-episode psychosis using a probabilistic model combining history, clinical assessment and fatty-acid biomarkers

Current criteria identifying patients with ultra-high risk of psychosis (UHR) have low specificity, and less than one-third of UHR cases experience transition to psychosis within 3 years of initial assessment. We explored whether a Bayesian probabilistic multimodal model, combining baseline historical and clinical risk factors with biomarkers (oxidative stress, cell membrane fatty acids, resting quantitative electroencephalography (qEEG)), could improve this specificity. We analyzed data of a UHR cohort (n=40) with a 1-year transition rate of 28%. Positive and negative likelihood ratios were calculated for predictor variables with statistically significant receiver operating characteristic curves (ROCs), which excluded oxidative stress markers and qEEG parameters as significant predictors of transition. We clustered significant variables into historical (history of drug use), clinical (Positive and Negative Symptoms Scale positive, negative and general scores and Global Assessment of Function) and biomarker (total omega-3, nervonic acid) groups, and calculated the post-test probability of transition for each group and for group combinations using the odds ratio form of Bayes' rule. Combination of the three variable groups vastly improved the specificity of prediction (area under ROC=0.919, sensitivity=72.73%, specificity=96.43%). In this sample, our model identified over 70% of UHR patients who transitioned within 1 year, compared with 28% identified by standard UHR criteria. The model classified 77% of cases as very high or low risk (P>0.9, <0.1) based on history and clinical assessment, suggesting that a staged approach could be most efficient, reserving fatty-acid markers for 23% of cases remaining at intermediate probability following bedside interview.

A dimensional comparison between delusional disorder, schizophrenia and schizoaffective disorder

INTRODUCTION

Since the early description of paranoia, the nosology of delusional disorder has always been controversial. The old idea of unitary psychosis has now gained some renewed value from the dimensional continuum model of psychotic symptoms.

AIMS

1. To study the psychopathological dimensions of the psychosis spectrum; 2. to explore the association between psychotic dimensions and categorical diagnoses; 3. to compare the different psychotic disorders from a psychopathological and functional point of view.

MATERIAL AND METHODS

This is an observational study utilizing a sample of some 550 patients with a psychotic disorder. 373 participants had a diagnosis of schizophrenia, 137 had delusional disorder and 40 with a diagnosis of schizoaffective disorder. The PANSS was used to elicit psychopathology and global functioning was ascertained using the GAF measure. Both exploratory and confirmatory factor analyses of the PANSS items were performed to extract psychopathological dimensions. Associations between diagnostic categories and dimensions were subsequently studied using ANOVA tests.

RESULTS

5 dimensions - manic, negative symptoms, depression, positive symptoms and cognitive - emerged. The model explained 57.27% of the total variance. The dimensional model was useful to explained differences and similarities between all three psychosis spectrum categories. The potential clinical usefulness of this dimensional model within and between clinical psychosis spectrum categories is discussed.

Delusional disorder and schizophrenia: a comparison of the neurocognitive and clinical characteristics in first-episode patients

BACKGROUND

Delusional disorder (DD) is thought to be distinct from schizophrenia (SZ). However, few systematic investigations have been conducted on DD because of the difficulty in ascertaining a representative sample size. Existing knowledge has been mostly generated from inpatient cohorts, which may be biased towards a more severe sample.

METHOD

We compared the demographic, clinical and cognitive differences between 71 patients with first-episode DD and 71 age-matched patients with first-episode SZ. Participants were consecutively recruited from a population-based territory-wide study of early psychosis in Hong Kong targeting first-episode psychosis. Basic demographic information, premorbid functioning, duration of untreated psychosis, pathways to care, symptomatology, social, occupational, and cognitive functioning were comprehensively assessed using standardized measurements.

RESULTS

Patients with DD had less premorbid schizoid and schizotypal traits compared to patients with SZ. More patients with DD were married compared to patients with SZ. However, at first episode, there were no significant differences between the two groups in regards to the duration of untreated psychosis, pathways to care, symptom severity, neurocognitive performance, treatment, and functioning.

CONCLUSIONS

Our findings challenge previous thinking that patients with DD had better functioning than patients with SZ. This study not only provides an updated perspective into conceptualizing the clinical differences between DD and SZ, but also expands the descriptive account of the two disorders to include the neurocognitive dimension.

[The Influence of Threatening Stimuli on the Component P200 in Patients with Paranoid Schizophrenia]

We studied schizophrenic patients with the dominance of pseudohallucinations. As is well known, pseudohallucinations are the main syndrome of schizophrenia, the so-called first rank syndrome. Pseudohallucinations are defined as a disorder of sense (affective) perception. This disorder is mainly diagnosed from the clinical picture or by pathopsychologichal observations. We investigated the evoked potentials (EP) of brain after neutral and emotionally meaningful (threatening) visual stimuli in order to specify the neurophysiological disorders of affective perception in schizophrenic patients with severe paranoid-hallucinatory syndrome who did not receive neuroleptic therapy. The analysis of P200 component in healthy subjects showed an increase in the amplitude and shortening of the latency of this wave in response to thretaning stimuli, as compared to neutral stimuli. In the group of patients with schizophrenia, the analysis showed the same increase in the level of excitation in response to emotionally threatening stimuli. However, in schizophrenic patients there were also found certain areas where the amplitude and latency decreased or increased at the same time. The results show that patients with schizophrenia have the pathological effect of having parameters typical of the processes of both excitation and inhibition.

[Neurophysiological Features of Perception of Emotional Stimuli in Health and in Patients with Paranoid Schizophrenia]

Cognitive and emotional disorders, as far as is known, are the main syndromes of schizophrenia. Disorders of these functions are mainly determined by the clinical picture, as well as by psychophysiological correlates. The purpose of our study was to identify some psychophysiological factors which cause perceptual and emotional disturbances in patients with schizophrenia. These disorders of mental functions form the first rank (top) syndrome in patients with schizophrenia [1]. The studied patients had acute psychosis with a predominance of paranoid hallucinatory syndrome and did not receive antipsychotic therapy; i.e., the disturbances of sensory perception were most pronounced. The analysis of early component P100 and intermediate one N170 of event related potentials (ERPs) in the control group showed an increased level of excitation in response to emotionally threatening stimuli; the amplitude increased and the latency decreased in all leads. In contrast the analysis of components P100 and N170 in the group of patients with schizophrenia showed the increased latency and decreased amplitude. The obtained data provide evidence of pathological inhibition in the passive perception of emotionally significant stimuli.

High-resolution joint symbolic analysis to enhance classification of the cardiorespiratory system in patients with schizophrenia and their relatives

Schizophrenia as a mental illness is one of the most serious in the world. Patients with schizophrenia have an increased cardiac mortality rate, but the reasons for this remain unclear. In addition to other factors, the role of impaired autonomic regulation during acute psychosis has become more evident in different studies applying heart rate (HR) variability analyses. But, until now, respiration and cardiorespiratory regulation, which are important for homeostatic control, have not been considered. In this study, short-term cardiorespiratory couplings (CRCs) of 23 unmedicated patients with paranoid schizophrenia (SZO), 20 of their healthy first-degree relatives (REL) and 20 healthy subjects (CON) matched according to age and sex of SZO and REL were investigated by applying high-resolution joint symbolic dynamics (HRJSD) analysis. We found a significantly (p<0.0061) altered HR pattern, respiratory pattern and CRCs in SZO and only marginal alterations for the REL group in comparison with the CON group when we applied HRJSD. These results might be an indication of decreased vagal activity within the brainstem, an altered or suppressed interaction of the brainstem and higher regulatory centres, or panic- and anxiety-related changes in the brainstem associated with the acute psychosis of these patients.

History of religious delusions and psychosocial functioning among Mexican patients with paranoid schizophrenia

The association between global functionality and religiosity among patients from developing and predominantly Catholic countries warrants attention. To compare religiosity and psychosocial functioning in Mexican schizophrenia patients with and without a history of religious delusions, seventy-four patients with paranoid schizophrenia were recruited. Patients with a history of religious delusions had more psychiatric hospitalizations and poorer psychosocial functioning compared with those without a history of religious delusions. No differences emerged between groups in the total scores of religiosity scales. A history of religious delusions rather than religiosity itself may have an influence on psychosocial functioning among Mexican patients with schizophrenia.

Delusional disorder as a partial psychosis

In his textbook from 1838, Esquirol made the first comprehensive psychopathological description of paranoia, which he labeled partial psychosis. This was a condition with encapsulated, well organized, and persistent delusions. These are defended with a great deal of emotions and sharp argument. The individual appears quite convincing, especially because he or she otherwise behaves rationally. The intellectual capacity is used to achieve defined goals according to the delusional content. This condition is difficult to uncover because of dissimulation and adaptation. The frequency in the population is unknown, but the condition is rare in psychiatric treatment facilities, and usually only when the persons become litigious or criminal. In Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, the condition is covered by the concept of delusional disorder, but that concept also comprises benign acute/subacute conditions as well as cases that turn out to have the diagnosis changed to schizophrenia.

Attributional style in fist episode of schizophrenia and schizophrenia spectrum disorders with and without paranoid ideation

In the present study we evaluated attributional style which refers to how individuals explain the causes for positive and negative events in their lives in patients with first episode of schizophrenia with and without paranoid ideation. 43 patients with first episode of psychosis and 37 matched normal controls completed Ambiguous Intentions Hostility Questionnaire (AIHQ) (Combs et al. 2007). Between group comparison of AIHQ scores showed a notable tendency to show aggressive response in overall patients group. We obtained significant elevation of hostility and blame biases scores in intentional and accidental situations in patients with paranoid ideation while the patients with non-paranoid ideation showed greater hostility and blame biases only in accidental situations as compared to controls. Correlations with positive and negative symptoms were obtained. Our findings suggest that patients with first episode of psychosis exhibit difficulties of the attribution biases which are interconnected with symptoms and thus indicate a trait-deficit of attributional style.

Deficits in executive and memory processes in delusional disorder: a case-control study

OBJECTIVE

Delusional disorder has been traditionally considered a psychotic syndrome that does not evolve to cognitive deterioration. However, to date, very little empirical research has been done to explore cognitive executive components and memory processes in Delusional Disorder patients. This study will investigate whether patients with delusional disorder are intact in both executive function components (such as flexibility, impulsivity and updating components) and memory processes (such as immediate, short term and long term recall, learning and recognition).

METHODS

A large sample of patients with delusional disorder (n = 86) and a group of healthy controls (n = 343) were compared with regard to their performance in a broad battery of neuropsychological tests including Trail Making Test, Wisconsin Card Sorting Test, Colour-Word Stroop Test, and Complutense Verbal Learning Test (TAVEC).

RESULTS

When compared to controls, cases of delusional disorder showed a significantly poorer performance in most cognitive tests. Thus, we demonstrate deficits in flexibility, impulsivity and updating components of executive functions as well as in memory processes. These findings held significant after taking into account sex, age, educational level and premorbid IQ.

CONCLUSIONS

Our results do not support the traditional notion of patients with delusional disorder being cognitively intact.

Spatial distribution and cognitive correlates of gamma noise power in schizophrenia

BACKGROUND

Brain activity is less organized in patients with schizophrenia than in healthy controls (HC). Noise power (scalp-recorded electroencephalographic activity unlocked to stimuli) may be of use for studying this disorganization. Method Fifty-four patients with schizophrenia (29 minimally treated and 25 stable treated), 23 first-degree relatives and 27 HC underwent clinical and cognitive assessments and an electroencephalographic recording during an oddball P300 paradigm to calculate noise power magnitude in the gamma band. We used a principal component analysis (PCA) to determine the factor structure of gamma noise power values across electrodes and the clinical and cognitive correlates of the resulting factors.

RESULTS

The PCA revealed three noise power factors, roughly corresponding to the default mode network (DMN), frontal and occipital regions respectively. Patients showed higher gamma noise power loadings in the first factor when compared to HC and first-degree relatives. In the patients, frontal gamma noise factor scores related significantly and inversely to working memory and problem-solving performance. There were no associations with symptoms.

CONCLUSIONS

There is an elevated gamma activity unrelated to task processing over regions coherent with the DMN topography in patients with schizophrenia. The same type of gamma activity over frontal regions is inversely related to performance in tasks with high involvement in these frontal areas. The idea of gamma noise as a possible biological marker for schizophrenia seems promising. Gamma noise might be of use in the study of underlying neurophysiological mechanisms involved in this disease.

Clinico-Epidemiological Comparison of Delusion-Prominent and Hallucination-Prominent Clinical Subgroups of Paranoid Schizophrenia

BACKGROUND

Though hallucinations and delusions are prominent basic impairments in schizophrenia, reports of the relationship between hallucinatory and delusional symptoms among schizophrenia patients are scant.

AIMS

To examine the epidemiological and clinical differences between mainly hallucinatory and mainly delusional subgroups of paranoid schizophrenia patients.

METHODS

One hundred schizophrenia patients, paranoid type, were recruited. In a cross-sectional study, participants were divided into Mainly Hallucinatory (H) and Mainly Delusional (D) subgroups. Demographic variables were compared and clinical characteristics were evaluated using the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impression Scale. The Quality-of-Life Enjoyment and Satisfaction Questionnaire-18 was used to assess quality of life.

RESULTS

Clinically, the H group was more heterogeneous as expressed by the broader range of scores that described the clinical picture of patients in that subgroup (in 43 of 78 variables, 55.13%) and similar ranges of scores (31 of 78 variables, 39.74%) for patients in the D group. Duration of hospitalization was significantly longer in group H than in group D (p=0.047). There was no statistically significant difference between the H and D subgroups in demographic characteristics.

CONCLUSIONS

There are distinct epidemiological and clinical differences between the H and D subgroups, with more severe positive and negative symptoms and greater functional impairment in the H group. Paranoid schizophrenia patients with prominent hallucinations have poorer prognosis and need intensive therapeutic rehabilitation beginning with onset-of-illness. Further genetic studies and comparisons of fMRI and/or PET findings are warranted to investigate additional distinctive characteristics of these subgroups.

[Impairment of attention and executive functions in patients with paranoid schizophrenia]

To study changes in attention and executive functions during psychopharmacotherapy in patients with paranoid schizophrenia, we have examined 120 patients with a first episode of paranoid schizophrenia treated with typical and atypical neuroleptics. Clinical and statistical analyses have revealed the heterogeneity within treatment groups that allowed to define two subgroups. These subgroups were characterized by a differed disease course (favorable or poor type). Before remission was achieved, the effect of atypical neuroleptics on cognitive performance was higher compared to typical neuroleptics. After remission, when doses of neuroleptics were decreased, a type of disease course played a main role. At 6 months after remission, attention and executive functions have improved in subgroups with favorable course of disease regardless of treatment.

[Event-related potentials P₃₀₀ with memory function and psychopathology in first-episode paranoid schizophrenia]

OBJECTIVE

To investigate the variability of event-related potentials P(300) and the relationship with memory function/psychopathology in patients with first-episode paranoid schizophrenia.

METHODS

Thirty patients with first-episode paranoid schizophrenia (patient group) and twenty health subjects (control group) were enrolled in the study. The auditory event-related potentials P₃₀₀ at the scalp electrodes Cz, Pz and Wechsler Memory Scale (WMS) were examined in both groups, Positive And Negative Syndrome Scale (PANSS) was evaluated in patient group.

RESULTS

In comparison with control group, patients had longer latency of P₃₀₀ [(390.6 ± 47.6)ms at Cz and (393.3 ± 50.1)ms at Pz] (P<0.01), lower amplitude of P₃₀₀ [(7.7 ± 3.4) μV at Cz and (8.5 ± 3.9)μV at Pz] (P<0.05-0.01). The memory quotient (88.1 ± 10.0) scores and short-term memory, immediate memory in patient group were damaged significantly (P<0.05-0.01). In patient group, the latency of P300 was correlated positively with PANSS scores and negatively with WMS scores (P<0.05-0.01).

CONCLUSION

First-episode paranoid schizophrenia has memory deficit, which can be evaluated comprehensively by P₃₀₀ and WMS. The longer latency of P₃₀₀ might be associated with the increased severity of first-episode paranoid schizophrenia.

[Facial emotion perception in schizophrenia: relationships with cognitive and social functioning]

Evidence suggests that facial emotion recognition is disturbed in schizophrenic patients however its nature has not been elucidated. Affect recognition is an important aspect of psychosocial functioning.

AIM

In this study we assessed recognition of facial emotional expression in schizophrenic patients and its relationship with selected clinical and neuropsychological variables as well as with social functioning.

METHOD

We used Penn Emotional Facial Recognition (ER40) task, Wisconsin Card Sorting Test WCST, Social Functioning Scale. Twenty-three patients who met the DSM-IV criteria for schizophrenia -paranoid type, hospitalised at the Department of Adult Psychiatry University of Medical Sciences in Poznań, Poland were involved in the study. The control group of healthy volunteers matched for gender and age was included.

RESULTS

Schizophrenic patients performed worse on emotion recognition test than the control group. The relationship between results of ER-40 and WCST and severity of negative symptoms was found.

CONCLUSION

Cognitive dysfunctions and disturbances of facial emotion recognition are closely linked in patients with schizophrenia, however casual relationships and relation to symptomatology remains unclear and further studies are necessary.

John Nash, game theory, and the schizophrenic brain

This article focuses on John Nash, recipient of the Nobel Prize in Economics in 1994, and subject of the Award winning 2001 film A Beautiful Mind, who was diagnosed with paranoid schizophrenia in 1958 at the age of 29. After presenting an account of the emergence, course, and eventual remission of his illness, the article argues for the relevance of his contribution to game theory, known as the Nash equilibrium, for which he received the Nobel Prize, to research studies of the schizophrenic brain and how it deviates from the normal brain. The case is made that the Nash equilibrium is descriptive of the normal brain, whereas the game theory formulated by John van Neumann, which Nash's theory challenges, is descriptive of the schizophrenic brain. The fact that Nash and his colleagues in mathematics did not make the association between his contributions to mathematics and his mental breakdown and that his later recovery exemplified the validity of this contribution are noted and discussed. Religious themes in his delusional system, including his view of himself as a secret messianic figure and the biblical Esau, are interpreted in light of these competing game theories and the dysfunctions of the schizophrenic brain. His recognition that his return to normalcy came at the price of his sense of being in relation to the cosmos is also noted.

Virtual reality to study responses to social environmental stressors in individuals with and without psychosis

A Virtual Reality (VR) environment was created to study psychotic symptoms in patients and non-patients. Participants' task was to find five virtual characters that each had a small number label on his or her chest. The density and ethnic appearance of the virtual characters in the bar was controlled. For a non-patient group (N=24), results showed a significant main effect for density on participants' physiological responses, their behavior, reported level of discomfort, and their ability to remember place and location of the numbered avatars. The avatar's ethnicity had a significant effect on non-patients' physiological responses. Comparison between two patients and non-patient group showed differences in physiological responses, behavior and reported level of discomfort.

The allusive cognitive deficit in paranoia: the case for mental time travel or cognitive self-projection

Delusional beliefs are characteristic of psychosis and, of the delusions, the paranoid delusion is the single most common type associated with psychosis. The many years of research focused on neurocognition in schizophrenia, using standardized neurocognitive tests, have failed to find conclusive cognitive deficits in relation to positive symptoms. However, UK-based psychological research has identified sociocognitive anomalies in relation to paranoid thinking in the form of theory of mind (ToM), causal reasoning and threat-related processing anomalies. Drawing from recent neuroscientific research on the default mode network, this paper asserts that the common theme running through the psychological tests that are sensitive to the cognitive impairment of paranoia is the need to cognitively project the self through time, referred to as mental time travel. Such an understanding of the cognitive roots of paranoid ideation provides a synthesis between psychological and biological accounts of psychosis while also retaining the powerful argument that understanding abnormal thinking must start with models of normal cognition. This is the core theme running through the cognitive psychological literature of psychiatric disorders that enables research from this area to inform psychological therapy.

Male genital self-mutilation as a psychotic solution

BACKGROUND

Male genital self-mutilation (GSM) is a rare, but serious phenomenon. Some of the risk factors for this act are: presence of religious delusions, command hallucinations, low self-esteem and feelings of guilt associated with sexual offences. Other risk factors include failures in the male role, problems in the early developmental period, such as experiencing difficulties in male identification and persistence of incestuous desires, depression and having a history of GSM. The eponym Klingsor Syndrome, which involves the presence of religious delusions, is proposed for GSM.

DATA SECTION

Four male GSM cases are presented: Case 1 and Case 2 were diagnosed with schizophrenia, Case 3 with schizophrenia and depressive disorder, not otherwise specified, and Case 4 with bipolar depression with psychotic features.

DISCUSSION

All definite and probable motives and cultural aspects for their GSM are discussed. Atonement is proposed as a new concept in formulating religiously themed psychotic male GSM.

[Development of schizophrenia-spectrum psychoses caused by psychotraumatic events]

A study included 213 patients diagnosed with schizoaffective disorder (56.3%) or paranoid schizophrenia (43.7%). In all patients, psychotic symptoms developed under the influence of psychogenic factors. The high percentage of pathological personality disorders (50.2%), neurotic disorders (52.1%) and psychogenic depressive disturbances (53.5%) in the premorbid were found that indirectly indicates a liability to psychogenically caused endogenous psychoses. Three stages of development of schizophrenia-spectrum psychosis under the influence of psychogenic factors were singled out: psychogenic, endogenous-reactive (interim states) and endogenous psychotic disorders. Clinically heterogenic interim syndromes were specified as endogenous-reactive dysthymia (51.2%), obsessive-delusional syndrome (7.5%), hysteriform psychosis (20.2%) and endoreactive paranoia (21.2%). Psychotraumatic events caused three variants of schizophrenia-spectrum psychosis: affective, neurosis-like and paranoia. In conclusion, variants of the pathokinesis of psychogenically caused schizophrenia-spectrum psychosis predict the further course of endogenous process.

Social predictors of psychotic experiences: specificity and psychological mechanisms

It has become widely accepted that the psychotic disorders are endpoints of atypical developmental trajectories indexed by abnormal emotional and cognitive development early in life. However, the role of environmental factors in determining these trajectories has received relatively little attention. In this article, we argue that (1) the influence of environment on psychosis can best be understood if we focus on specific types of psychotic experiences such as hallucinations and delusions, (2) these symptoms are the products of specific cognitive biases and deficits, and (3) the development of these particular patterns of cognitive functioning is influenced by specific kinds of environmental adversity. This approach is at variance with more conventional approaches because it suggests that each type of experience, rather than being the manifestation of a common underlying illness process, is a product of a specific set of causal variables. Importantly, these variables include environmental determinants, although not to the exclusion of endogenous factors such as neurodevelopmental impairment or genetic vulnerability. We discuss the implications of this approach for neurobiological and genetic research into psychosis, as well as clinical practice.

Neurochemical and structural correlates of executive dysfunction in schizophrenia

BACKGROUND

Executive dysfunction is a core feature of schizophrenia. The neurochemical and structural changes associated with this deficit are, however, largely unclear. This study tested the hypothesis that changes in glutamate, glutamine and N-acetyl-aspartate (NAA) in hippocampal and dorsolateral prefrontal (DLPFC) regions as well as hippocampal, amygdalar and DLPFC volume reductions are associated with executive dysfunction.

METHODS

Twenty-nine subjects with schizophrenia and 31 healthy controls were examined by short-echo single voxel magnetic resonance spectroscopy of the left anterior hippocampus and the left DLPFC. Volumes of the hippocampi, amygdalae and DLPFC were measured bilaterally using manual volumetry. Executive functioning was assessed by the Wisconsin Card Sorting Test (WCST).

RESULTS

Poor WCST performance was associated with increased hippocampal glutamate concentrations among subjects with schizophrenia, not among healthy controls. Glutamate in the DLPFC as well as NAA or glutamine in the hippocampus or the DLPFC were not related to executive functioning in schizophrenia or healthy controls. Reduced amygdalar volume was associated with impaired executive functioning in subjects with schizophrenia (p=.06) and healthy controls (p=.04).

CONCLUSIONS

Altered hippocampal glutamatergic neurotransmission and amygdalar volume loss may be associated with executive dysfunction in schizophrenia.

Relationship between cardiovagal modulation and psychotic state in patients with paranoid schizophrenia

Disturbed autonomic nervous system (ANS) function in schizophrenia might contribute to increased cardiovascular mortality. We obtained heart rate variability indices from 40 unmedicated schizophrenic patients and 58 matched controls. Mainly we found that patients displaying stronger psychotic symptoms as assessed by the Brief Psychiatric Rating Scale exhibit more severe cardiac ANS disturbances compared with controls.

The neurology of psychosis

The neural basis of psychosis is yet to be fully elucidated. In this review the contribution of schizophrenia-like psychosis of epilepsy, delusional misidentification syndromes and psychotic phenomena, such as auditory and visual hallucinations, to our understanding of the neural basis of psychosis is examined. Schizophrenia-like psychosis of epilepsy is associated with seizures originating from the limbic structures. Reduced seizure frequency, left-sided electrical foci, and neurodevelopmental lesions manifesting as cortical dysgenesis are known to influence the likelihood of developing schizophrenia-like psychosis of epilepsy. The delusional misidentification syndromes are a group of rare psychiatric symptoms in which impairments of face recognition memory are present. These conditions appear also to be associated with organic lesions affecting limbic structures and also involving both the frontal and parietal lobes. There is evidence that right-sided lesions predominate in the aetiology of delusional misidentification syndromes. Thus, the common link between schizophrenia, schizophrenia-like psychosis of epilepsy and delusional misidentification syndromes appears to be involvement of limbic structures in their pathophysiology. Discrete psychotic phenomena such as visual and auditory hallucinations appear to arise from functional changes in the same cortical areas subserving the normal physiological functions of vision and audition but also involving limbic structures. In conclusion, the limbic structures appear to be central to the psychopathology of psychosis but with involvement of frontal and parietal structures. These inquiries are revealing as much about psychosis as they are about the nature of normal brain function.

Functional disintegration in paranoid schizophrenia using resting-state fMRI

Functional disintegration has been observed in schizophrenia during task performance. We sought to investigate functional disintegration during rest because an intrinsic functional brain organization, including both "task-negative" (i.e., "default mode") and "task-positive" networks, has been suggested to play an important role in integrating ongoing information processing. Additionally, the brain regions that are involved in the intrinsic organization are believed to be abnormal in schizophrenia. Patients with paranoid schizophrenia (N=18) and healthy volunteers (N=18) underwent a resting-state fMRI scan. Functional connectivity analysis was used to identify the connectivity between each pair of brain regions within this intrinsic organization, and differences were examined in patients versus healthy volunteers. Compared to healthy volunteers, patients showed significant differences in connectivity within networks and between networks, most notably in the connectivities associated with the bilateral dorsal medial prefrontal cortex, the lateral parietal region, the inferior temporal gyrus of the "task-negative" network and with the right dorsolateral prefrontal cortex and the right dorsal premotor cortex of the "task-positive" network. These results suggested that the interregional functional connectivities in the intrinsic organization are altered in patients with paranoid schizophrenia. These abnormalities could be the source of abnormalities in the coordination of and competition between information processing activities in the resting brain of paranoid patients.

Selective anterior cingulate cortex deficit during conflict solution in schizophrenia: an event-related potential study

BACKGROUND

Schizophrenia research has gained a new focus on identification and further characterization of neurocognitive deficits in the search for behavioural endophenotypes of this disorder. The objective of this study was to explore differential cortical processing during executive control in schizophrenia as assessed with the attention network test (ANT).

METHODS

Sixteen schizophrenic patients and sixteen healthy controls matched for gender, age, education, and nicotine consumption were tested with the ANT while recording 29-channel-electroencephalogram (EEG). Visual event-related potentials (ERP) N200 and P300 were topographically analyzed and cortical mapping using low resolution brain electromagnetic tomography (LORETA) was applied to localize neuroelectric generators of ERP.

RESULTS

Behaviourally, significant differences between schizophrenic patients and controls were found only for the conflict condition (p<0.05) and for conflict adjusted by mean reaction time (p<0.01). Examining ERP of control subjects, N200 failed to show robust flanker congruency effects. P300 amplitude was reduced at Pz (p<0.05) and P300 latency was increased at Cz (p<0.005) for the conflict condition. Schizophrenic patients differed significantly in P300 latency at Cz during late conflict processing (p<0.005). Source analysis revealed a deficit in anterior cingulate cortex (p<0.05).

CONCLUSION

Our results are in line with previous reports about dysfunctional ACC activation in schizophrenia and argue in favour of a selective deficit of cortical conflict resolution. It is further proposed that dysfunctional ACC activation during executive processing may be a neurophysiologic endophenotype candidate of schizophrenia.

Investigation of explicit verbal memory in patient with paranoid schizophrenia and their first degree relatives

The aim of the current study is to characterize the prevalence, degree and nature of verbal memory deficit in schizophrenia; to study verbal memory task performance in patient with paranoid schizophrenia and their first degree relatives in order to identify, trait cognitive marker of the disorder. Besides the authors studied, whether nonpsychotic relatives of schizophrenic probands had an elevated risk of deficits in cognitive functioning, and, which of specific factors: gender, age, education, illness duration, diagnosis and psychopathological symptoms influenced the tests performance. Twenty schizophrenia inpatients (10 men; mean age=34.2 years, SD=9.1; mean education=13.6 years, SD=2.6) were recruited from the psychiatric hospital. All patients met DSM-IV criteria for schizophrenia and clinically assessed by SANS (negative symptoms) and SAPS (positive symptoms). The patients had no history of neurological disease, systemic disease known to involve CNS functioning, clinically significant head injury, or mental retardation.

CONTROL GROUP

twenty-eight nonpsychiatric healthy volunteers (14 men; mean age=35.0 years, SD=10.7; mean education=14.3 years, SD=3.46) were recruited from the community. Schizophrenia patients showed significant impairment of the verbal memory in all domains. In contrast, their first degree relatives having the same education level as the patients did not differ considerably from healthy controls. These results indicate that, probably, the deterioration of explicit verbal memory is not associated with the predisposition for schizophrenia. As the test performance did not correlate with severity of symptoms this finding cannot be attributed to the distractibility due to active psychotic symptoms, or medication effects. Impaired performance on the CVLT task, a measure of explicit verbal working memory, appears to be associated with the cognitive deficits due to the disorder itself.

CSF metabolic and proteomic profiles in patients prodromal for psychosis

BACKGROUND

The initial prodromal state of psychosis (IPS) is defined as an early disease stage prior to the onset of overt psychosis characterized by sub-threshold or more unspecific psychiatric symptoms. Little is known regarding the biochemical changes during this period.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the metabolic/proteomic profiles of cerebrospinal fluid (CSF) of first-onset drug naïve paranoid schizophrenia patients (n = 54) and individuals presenting with initial prodromal symptoms (n = 24), alongside healthy volunteers (n = 70) using proton nuclear magnetic resonance ((1)H-NMR) spectroscopy and surface enhanced laser desorption ionization (SELDI) mass spectrometry, respectively. Partial least square discriminant analysis (PLS-DA) showed that 36%/29% of IPS patients displayed proteomic/metabolic profiles characteristic of first-onset, drug naïve schizophrenia, i.e., changes in levels of glucose and lactate as well as changes in a VGF-derived peptide (VGF23-62) and transthyretin protein concentrations. However, only 29% (n = 7) of the investigated IPS patients (who to date have been followed up for up to three years) have so far received a diagnosis of schizophrenia. The presence of biochemical alterations in the IPS group did not correlate with the risk to develop schizophrenia.

CONCLUSIONS/SIGNIFICANCE

Our results imply that schizophrenia-related biochemical disease processes can be traced in CSF of prodromal patients. However, the biochemical disturbances identified in IPS patients, at least when measured at a single time point, may not be sufficient to predict clinical outcome.

Simulating biological and non-biological motion

It is widely accepted that the brain processes biological and non-biological movements in distinct neural circuits. Biological motion, in contrast to non-biological motion, refers to active movements of living beings. Aim of our experiment was to investigate the mechanisms underlying mental simulation of these two movement types. Subjects had to either simulate mentally or to overtly reproduce previously executed or observed movements. Healthy subjects showed a very high timing precision when simulating biological and a strong distortion when simulating non-biological movements. Schizophrenic subjects, however, showed the opposite. Since overt reproduction was precise in any case, this double dissociation shows that processes underlying mental simulation of biological and non-biological movements are separate from each other and from perceptual and motor-control processes.

Neuropsychologische Aspekte wahnhafter Störungen

BACKGROUND

"Pure" delusional disorders are clinically rare, and the neuropsychology of such disorders is poorly understood. Whereas "deficit" models suggest a cognitive impairment accounting for the incorrigible fixation of false beliefs, cognitive models propose the existence of a characteristic attributional style in patients to stabilise a fragile self.

PATIENTS AND METHODS

The cognitive flexibility and attributional style of 21 patients diagnosed with delusional disorder according to ICD-10 were compared with a group of healthy controls paralleled for age, sex, education, and intelligence.

RESULTS

Patients with delusional disorders made more errors and more perseverative errors in the Wisconsin Card Sorting Test compared with controls. However, these differences were only significant in patients with a comorbid depression. In contrast to earlier studies, patients with delusional disorders did not attribute negative events to external or personal causes more often than healthy controls, but partly tended to show a depressive attributional style.

CONCLUSION

Our results do not support either a cognitive deficit in patients with delusional disorders or a characteristic attributional style. In terms of treatment recommendations, a thorough diagnosis of comorbid depressive disorders in patients with delusional disorders is warranted.

Second run of transcranial magnetic stimulation has no effects on persistent auditory hallucinations

We report the case of a 30-year-old male schizophrenic patient with persistent auditory hallucinations (AHs) who had received two 1-Hz transcranial magnetic stimulations (TMS) to the left temporoparietal cortex. The patient had suffered from severe persistent AHs for more than 5 years with little improvement in response to various types of combination pharmacotherapy of antipsychotics. Upon commencement of TMS, however, the patient reported substantial improvement by the end of the third week of the treatment. The patient was discharged, but readmitted 6 months later because his AHs returned to their initial severity. A second run of TMS had no therapeutic effect. Further research is needed to establish the therapeutic duration of TMS treatment and to assess whether the second run of TMS after AH re-occurrence has therapeutic benefits.

Mismatch negativity in paranoid, schizotypal, and antisocial personality disorders

AIMS

The mismatch negativity (MMN) to frequency deviant tones has yielded conflicting results in patients with schizophrenia. This might be because Axis I schizophrenia overlaps with Axis II diagnoses such as paranoid or schizotypal personality disorders. This study was designed to address this issue.

METHODS

We evaluated the auditory MMN to frequency deviance in 17 patients with paranoid, 15 schizotypal, and 16 antisocial personality disorders. These were compared to 25 healthy subjects.

RESULTS

N1 to both deviant and standard tones was shorter in the paranoid group when compared to healthy controls. MMN latencies were shorter at Fz, Cz, and Pz in the paranoid group when compared to healthy controls, schizotypal, and antisocial groups. MMN amplitudes were higher at Fz and Cz in the schizotypal and antisocial groups when compared to healthy controls and the paranoid group.

CONCLUSIONS

Patients with paranoid personality disorder had faster automatic detection of auditory stimuli and of their change, but normal inhibition of irrelevant stimuli. By contrast, patients with schizotypal and antisocial personality disorders had normal discrimination of the auditory stimuli, but might have a deficit in inhibition on irrelevant stimuli. Our results might help differentiate these personality types, and clarify some MMN findings in schizophrenia.

Neural responses to dynamic expressions of fear in schizophrenia

Abnormalities in social functioning are a significant feature of schizophrenia. One critical aspect of these abnormalities is the difficulty these individuals have with the recognition of facial emotions, particularly negative expressions such as fear. The present work focuses on fear perception and its relationship to the paranoid symptoms of schizophrenia, specifically, how underlying limbic system structures (i.e. the amygdala) react when probed with dynamic fearful facial expressions. Seven paranoid and eight non-paranoid subjects (all males) with a diagnosis of schizophrenia took part in functional magnetic resonance imaging study (1.5T) examining neural responses to emerging fearful expressions contrasted with dissipating fearful expressions. Subjects viewed emerging and dissipating expressions while completing a gender discrimination task. Their brain activation was compared to that of 10 healthy male subjects. Increased hippocampal activation was seen in the non-paranoid group, while abnormalities in the bilateral amygdalae were observed only in the paranoid individuals. These patterns may represent trait-related hippocampal dysfunction, coupled with state (specifically paranoia) related amygdala abnormalities. The findings are discussed in light of models of paranoia in schizophrenia.

Dopamine D2 receptor binding in drug-naïve patients with schizophrenia examined with raclopride-C11 and positron emission tomography

The aim was to test the dopamine hypothesis of schizophrenia in a further analysis of D(2)-like dopamine binding using the radioligand [(11)C]raclopride and high resolution 3-dimensional (3D) PET. Eighteen drug-naive patients with schizophrenia and seventeen control subjects were examined. The D(2) binding potential (BP) in the putamen, the caudate and the thalamus was calculated using the simplified reference tissue model. The volume of regions of interest was controlled for by MRI. Symptoms were rated with the Positive and Negative Syndrome Scale for Schizophrenia (PANSS). No significant group differences were found for D(2) BP in the putamen or in the caudate and there was no significant hemispheric difference for any region. In the right thalamus the D(2) BP was significantly lower in patients as compared to control subjects, whereas a numerical difference did not reach statistical significance for the left thalamus. There was no significant correlation between D(2) BP and total PANSS score in any region. There was a highly significant age effect in the caudate and in the putamen, but not in the thalamus. In this relatively large PET study of exclusively drug-naive schizophrenic patients, a lower D(2) BP in the right thalamus was found in the patient group. This finding is in agreement with two previous studies in Sweden and in Japan using the high-affinity radioligand [(11)C]FLB 457 and provide further support for a role of dopamine in the thalamus related to the pathophysiology of schizophrenia.

Decreased baroreflex sensitivity in acute schizophrenia

Decreased vagal activity has been described in acute schizophrenia and might be associated with altered cardiovascular regulation and increased cardiac mortality. The aim of this study was to assess baroreflex sensitivity in the context of psychopathology. Twenty-one acute, psychotic, unmedicated patients with a diagnosis of paranoid schizophrenia were investigated after admission to the hospital. Results were compared with 21 healthy volunteers matched with respect to age and sex. Cardiovascular parameters obtained included measures for heart rate variability, baroreflex sensitivity, as well as cardiac output, left ventricular work index, and total peripheral resistance. All parameters investigated were analyzed using linear and novel nonlinear techniques. Positive and negative symptoms were assessed to estimate the impact of psychopathology on autonomic parameters. Subjects with acute schizophrenia showed reduction of baroreflex sensitivity accompanied by tachycardia and greatly increased left ventricular work index. Nonlinear parameters of baroreflex sensitivity correlated with positive symptoms. For heart rate variability, mainly parameters indicating parasympathetic modulation were decreased. Vascular pathology could be excluded as a confounding factor. These results reflect a dysfunctional cardiovascular regulation in acute schizophrenic patients at rest. The changes are similar to adaptational regulatory processes following stressful mental or physical tasks in healthy subjects. This study suggests that hyperarousal in acute schizophrenia is accompanied by decreased efferent vagal activity, thus increasing the risk for cardiovascular mortality. Future studies are warranted to examine the role of the sympathetic system and possible autonomic differences in hyperarousal induced by anxiety and/or external stressful events.

Behavioral inhibition system (BIS), behavioral activation system (BAS) and schizophrenia: relationship with psychopathology and physiology

OBJECTIVE

The Behavioral Inhibition System (BIS) and the Behavioral Activation System (BAS) have been conceptualized as two neural motivational systems that regulate sensitivity to punishment (BIS) and reward (BAS). Imbalance in BIS and BAS levels has been reported to be related to various forms of psychopathology. Since sensitivity to stress has been supposed to be a pathway for the development of psychotic symptoms, the aim of this study is to examine BIS and BAS scores in schizophrenia and their relationship with psychopathology and physiology.

METHOD

Forty-two patients with schizophrenia (26 men, 16 women), stable on atypical antipsychotics, and 37 healthy controls (17 men, 20 women) were assessed with the use of the Behavioral Inhibition and Behavioral Activation scales. Since increased average heart rate (HR) and decreased heart rate variability (HRV) have been reported in patients with schizophrenia and have been shown to correlate with inhibited behaviour, these psychophysiological measures were also obtained. The BIS/BAS data and HR/HRV data were both analyzed by a (M)ANOVA. Correlation coefficients were computed for associations between BIS/BAS data, HR/HRV data, and patient variables.

RESULTS

On the BIS, patients showed higher sensitivity to threat than control subjects. Higher BIS sensitivity correlated with longer duration of illness, and lower negative symptoms on the PANSS. The BAS scores did not reveal differences between patients and controls. In patients, low BAS sensitivity correlated with low dosage of medication. On the physiological measures patients showed a significantly higher HR and lower HRV compared to controls, which was limited to clozapine treated patients. No correlations were found between HR/HRV scores and BIS/BAS scores or patient variables.

CONCLUSIONS

Male as well as female patients with schizophrenia are more sensitive to threat than healthy controls. This may reflect a trait-related characteristic, and is not reflected in state-related psychophysiological measures.

Associations between serum brain-derived neurotrophic factor levels and clinical phenotypes in schizophrenia patients

This study investigated serum brain-derived neurotrophic factor (BDNF) protein levels in schizophrenia patients and healthy control subjects and schizophrenia patients with various clinical phenotypes. During a 1-year period, 126 schizophrenic patients and 96 healthy control subjects were recruited. Serum BDNF protein levels were measured using an ELISA Kit. Psychiatric diagnoses were made according to DSM-IV criteria. One-way analysis of variance (ANOVA) showed no significant differences in serum BDNF protein levels between schizophrenia and healthy normals. Additionally, no significant differences existed in BDNF levels between schizophrenia patients for the following variables: with/without a suicide attempt; antipsychotic drug use, family tendency and disease onset before and after 25 years old. However, patients with catatonic schizophrenia had lower serum BDNF protein levels than patients with paranoid or residual schizophrenia. These analytical results suggested that BDNF might play an important role in the clinical subtypes of schizophrenia, but it needed further investigation in future.