C. Silveira

Dysconnectivity Within the Default Mode in First-Episode Schizophrenia: A Stochastic Dynamic Causal Modeling Study With Functional Magnetic Resonance Imaging

We report the first stochastic dynamic causal modeling (sDCM) study of effective connectivity within the default mode network (DMN) in schizophrenia. Thirty-three patients (9 women, mean age = 25.0 years, SD = 5) with a first episode of psychosis and diagnosis of schizophrenia—according to the Diagnostic and Statistic Manual of Mental Disorders, 4th edition, revised criteria—were studied. Fifteen healthy control subjects (4 women, mean age = 24.6 years, SD = 4) were included for comparison. All subjects underwent resting state functional magnetic resonance imaging (fMRI) interspersed with 2 periods of continuous picture viewing. The anterior frontal (AF), posterior cingulate (PC), and the left and right parietal nodes of the DMN were localized in an unbiased fashion using data from 16 independent healthy volunteers (using an identical fMRI protocol). We used sDCM to estimate directed connections between and within nodes of the DMN, which were subsequently compared with t tests at the between subject level. The excitatory effect of the PC node on the AF node and the inhibitory self-connection of the AF node were significantly weaker in patients (mean values = 0.013 and −0.048 Hz, SD = 0.09 and 0.05, respectively) relative to healthy subjects (mean values = 0.084 and −0.088 Hz, SD = 0.15 and 0.77, respectively; P < .05). In summary, sDCM revealed reduced effective connectivity to the AF node of the DMN—reflecting a reduced postsynaptic efficacy of prefrontal afferents—in patients with first-episode schizophrenia.

The auditory P200 is both increased and reduced in schizophrenia? A meta-analytic dissociation of the effect for standard and target stimuli in the oddball task

OBJECTIVE Conflicting reports of P200 amplitude and latency in schizophrenia have suggested that this component is increased, reduced or does not differ from healthy subjects. A systematic review and meta-analysis were undertaken to accurately describe P200 deficits in auditory oddball tasks in schizophrenia. METHODS A systematic search identified 20 studies which were meta-analyzed. Effect size (ES) estimates were obtained: P200 amplitude and latency for target and standard tones at midline electrodes. RESULTS The ES obtained for amplitude (Cz) for standard and target stimuli indicate significant effects in opposite directions: standard stimuli elicit smaller P200 in patients (d = -0.36; 95% CI [-0.26, -0.08]); target stimuli elicit larger P200 in patients (d = 0.48; 95% CI [0.16, 0.82]). A similar effect occurs for latency at Cz, which is shorter for standards (d = -0.32; 95% CI [-0.54, -0.10]) and longer for targets (d = 0.42; 95% CI [0.23, 0.62]). Meta-regression analyses revealed that samples with more males show larger ES for amplitude of target stimuli, while the amount of medication was negatively associated with the ES for the latency of standards. CONCLUSIONS The results obtained suggest that claims of reduced or augmented P200 in schizophrenia based on the sole examination of standard or target stimuli fail to consider the stimulus effect. SIGNIFICANCE Quantification of effects for standard and target stimuli is a required first step to understand the nature of P200 deficits in schizophrenia.

More than one century of schizophrenia: an evolving perspective.

Abstract Schizophrenia is a very complex psychiatric disorder of unknown etiology, and there is controversy as to whether its name is even appropriate to describe the associated variety of clinical presentations and symptoms. Currently, the diagnosis is essentially based on clinical criteria. These enable a clinical profile to be recognized as encompassing positive symptoms, negative symptoms, disorganization of thinking and behavior, cognitive impairment, mood abnormalities, motor abnormalities, chronic clinical course, and incomplete remissions. The concept has evolved during the past century, and schizophrenia is currently questioned as a single disease entity. Established diagnostic criteria do not mirror the heterogeneity of the disorder. A strategy to deal with clinical heterogeneity in schizophrenia is, perhaps, the adoption of a classification system based on dimensions and stages. An additional strategy to deal with etiological and pathophysiological heterogeneity is to try to identify biomarkers, namely, on the basis of intermediate phenotypes. Despite extensive biological research, the biomarkers for schizophrenia are still lacking.

Effects of inter-stimulus interval (ISI) duration on the N1 and P2 components of the auditory event-related potential

The N1 and P2 components of the event-related potential are relevant markers in the processing of auditory information, indicating the presence of several acoustic phenomena, such as pure tones or speech sounds. In addition, the expression of these components seems to be sensitive to diverse experimental variations. The main purpose of the present investigation was to explore the role of inter-stimulus interval (ISI) on the N1 and P2 responses, considering two widely used experimental paradigms: a single tone task (1000 Hz sound repeated in a fixed rhythm) and an auditory oddball (80% of the stimuli were equal to the sound used in the single tone and the remaining were a 1500 Hz tone). Both tasks had four different conditions, and each one tested a fixed value of ISI (600, 1000, 3000, or 6000 ms). A sample of 22 participants performed these tasks, while an EEG was recorded, in order to examine the maximum amplitude of the N1 and P2 components. Analysis of the stimuli in the single tone task and the frequent tones in the oddball task revealed a similar outcome for both tasks and for both components: N1 and P2 amplitudes were enhanced in conditions with longer ISIs regardless of task. This response pattern emphasizes the dependence of both the N1 and P2 components on the ISI, especially in a scenario of repetitive and regular stimulation. The absence of task effects suggests that the ISI effect reported may depend on refractory mechanisms rather than being due to habituation effects.

Exploring the dynamics of P300 amplitude in patients with schizophrenia

This study investigated the time-frequency dynamics of P300 generation in patients with first-onset schizophrenia. A group of 40 patients with first-onset schizophrenia and 40 controls performed an auditory oddball task. Wavelet analysis of the single-trial data was used to compute the Event-Related Spectral Perturbation (ERSP) and the Inter-Trial Phase Coherence (ITC) for the delta, theta, alpha, beta and gamma bands on the 50ms window around peak P300 amplitude. The contribution of power and synchrony for P300 amplitudes was studied through correlation and regression analysis. Further, two sub-samples in which patients had lower or higher P300 amplitudes than their control match were contrasted. P300 amplitude did not differ between patients and controls. The frequency domain analysis revealed that controls display larger reductions on gamma power than patients. However, this gamma activity might be the result of micro-saccadic muscular artifacts. Regression analysis shows that P300 amplitude is highly dependent on delta power and synchronization. The analysis of the subsamples confirmed that while gamma power differences are dependent on the diagnosis, delta and theta synchronization are related to P300 amplitude, irrespective of diagnosis.

Similar sound intensity dependence of the N1 and P2 components of the auditory ERP: Averaged and single trial evidence

OBJECTIVE The literature suggests that the N1 and P2 waves of the auditory ERP are dissociable at the developmental, experimental, and source levels. At the experimental level, inconsistent findings suggest different effects of intensity on the amplitudes of the auditory N1 and P2. Our main goal was to analyze the intensity dependence of the auditory N1 and P2 while controlling for habituation effects. METHODS We examined the intensity dependence of both averaged and single-trial auditory N1 and P2 waves elicited in a repeated-stimulation protocol. RESULTS N1 and P2 revealed similar intensity dependence on both standard and filter denoised ERP, with a linear tendency for higher intensities to elicit higher absolute peak amplitudes. At the single-trial level, both waves covary irrespective of stimulus intensity and trial order. CONCLUSIONS Our results suggest that stimulus intensity variation induces similar effects on both and N1 and P2 and partially contradict previous data that classified the P2 as a non-habituating component. SIGNIFICANCE Our findings contribute to the ongoing discussion on the functional significance of the auditory P2 deflection. In addition, the present work demonstrated the applicability of a filter denoising method for single-trial estimation in the analysis of the experimental effects on auditory ERP components.

P01-422 - The relationship between neuropsychological, emotional and family functioning within a group of patients with multiple sclerosis

MS is a heterogeneous entity that varies in its etiology, classification, clinical course and sequelae, and is included as part of the chronic diseases that cause limitations in many areas. This study aims to assess neuropsychological functions, anxiety and depression in patients with MS, and realize that these variables can be influenced by family functioning. This study consists of a group of 25 individuals were women with diagnosis of Multiple Sclerosis (ages 25 to 58 years). Data collection was done through: a demographic questionnaire and clinical, a neuropsychological assessment battery (LNNB), a range of Hospital Anxiety and Depression Scale (HADS), and a questionnaire of family functioning (FACES-III). The results suggest that the group of patients evaluated present neuropsychological deficits in several areas, as well as depression and anxiety. They also suggest that there is a higher prevalence of neuropsychological deficits associated with a higher incidence of depressive symptoms and family dissatisfaction. Taken together, these results reveal an involvement of emotional and family functioning on neuropsychological functioning. As such, these factors should be considered in the implementation of intervention programs, both in terms of individual psychotherapy, or the level of family psychotherapy as well as in neuropsychological and psychosocial rehabilitation programs and these patients.

Forty years of a psychiatric day hospital

INTRODUCTION Day hospitals in psychiatry are a major alternative to inpatient care today, acting as key components of community and social psychiatry. OBJECTIVE To study trends in the use of psychiatric day hospitals over the last decades of the 20th century and the first decade of the 21st century, focusing on patient age, sex, and diagnostic group, using data from Centro Hospitalar São João, Porto, Portugal. METHODS Data corresponding to years 1970 to 2009 were collected from patient files. Patients were classified into seven diagnostic groups considering their primary diagnoses only. RESULTS Mean age upon admission rose from 32.7±12.1 years in the second half of the 1970s to 43.5±12.2 years in 2005-2009 (p for trend < 0.001). Most patients were female (63.2%), however their proportion decreased from nearly 70% in the 1970s to 60% in the first decade of the 21st century. In males, until the late 1980s, neurotic disorders (E) were the most common diagnosis, accounting for more than one third of admissions. In the subsequent years, this proportion decreased, and the number of admissions for schizophrenia (C) exceeded 50% in 2004- 2009. In females, until the late 1980s, affective disorders (D) and neurotic disorders (E), similarly distributed, accounted for most admissions. From the 1990s on, the proportion of neurotic disorders (E) substantially decreased, and affective disorders (D) came to represent more than 50% of all admissions. CONCLUSIONS Mean age upon admission rose with time, as did the percentage of female admissions, even though the latter tendency weakened in the last 10 years assessed. There was also an increase in the proportion of patients with schizophrenia.

EPA-0684 – Diagnostic stability three years after a first admission diagnosis of psychosis

Introduction The diagnosis of psychotic disorders is based on the presence or absence of characteristic symptoms. However the presence of such symptoms varies during the course and treatment of these illness, which raises the question of how stable a diagnosis of psychotic disorder remains over time. Objective The aim of this study was to assess the 3-year diagnostic stability after first admission for psychotic disorders. Methods We performed a retrospective study at the Department of Psychiatry of Centro Hospitalar S.Joao (Porto, Portugal). Patients were admitted in the inpatient unit from 2007 to 2010 (n=59), for a first psychotic episode experience and fulfilled criteria for one of the following diagnosis: Schizophrenia, Schizoaffective Disorder, Bipolar Affective Disorder, Psychotic Disorder due to Substance Use, Acute and Transient Psychotic Disorders and Psychosis NOS (ICD-10). The diagnoses were extracted from clinical records, and reassessed three years after the initial diagnosis. Twenty patients were lost to follow-up and thus excluded from the study. Results In our sample, 69.2% of the subjects kept the same diagnosis three years later and 30.8% were given a different diagnosis at follow-up. Schizophrenia and Bipolar Affective Disorder were the most stable diagnoses and Psychosis not otherwise specified and Acute and Transient Psychotic Disorder were more variable. Conclusions Diagnosis performed in the first episodes of mental disorders has important therapeutic and prognostic implications. With its characteristic fluctuating symptomatology, first episode psychosis may be more vulnerable to diagnostic change over time.

P-1308 - Clinical characterization of a sample of first psychotic episode inpatients: a retrospective study

Objectives Systematic characterization of the first psychotic episodes patients may be important in identifying subgroups of patients with a similar course of illness, and may ultimately facilitate diagnosis, treatment, and predicting outcome. The aim of this study was to characterize a population of first psychotic patients in different domains such as psychopathology, prodromal symptoms, drug abuse and socio - demographic variables. Methods This was a retrospective study carried out in the Department of Psychiatry of a large University Hospital (Centro Hospitalar Sao Joao, Porto, Portugal). Patients enrolled were admitted in the inpatient unit from 2007 to 2011, had experienced a first psychotic episode, and fulfilled criteria for one of the following diagnosis: schizophrenia, schizoaffective disorder, bipolar disorder, drug induced psychosis, acute and transient psychotic disorders, schizophreniform disorder and psychosis NOS (ICD-10 classification). Data were extracted from clinical records. The analysis focuses on clinical, demographic and social variables. Results The study is now under statistic evaluation.