Neurological soft signs and prepulse inhibition of the startle reflex in psychosis: A pilot study.

OBJECTIVE: Prepulse inhibition (PPI) of the startle reflex deficit and neurological soft signs (NSS) are two markers of vulnerability to psychosis. This study investigated the possibility of a PPI-NSS relation due to a putative common biological substrate, hypothesizing that patients with higher NSS scores also show higher PPI deficits. Moreover, we examined the possibility of an association of PPI deficits and NSS with negative symptoms. METHODS: Fifteen subjects with psychosis and fifteen healthy controls underwent PPI and NSS evaluations. RESULTS: Patients did not exhibit higher PPI deficits but only higher NSS rates (p < 0.01), as compared with healthy controls. Higher NSS rates were not associated with PPI deficits, and NSS sensory integration signs correlated positively with negative symptoms (p < 0.01). CONCLUSION: Our study supported the hypothesis that NSS are trait markers whereas PPI deficits state markers and that their putative common biological substrate is not sufficient to determinate an association between them. The study hypothesis, however, needs further investigation.

First-contact incidence of psychosis in north-eastern Italy: influence of age, gender, immigration and socioeconomic deprivation.

BACKGROUND: Considerable variations in the incidence of psychosis have been observed across countries, in terms of age, gender, immigration status, urbanicity and socioeconomic deprivation. AIMS: To evaluate the incidence rate of first-episode psychosis in a large area of north-eastern Italy and the distribution of the above-mentioned risk factors in individuals with psychoses. METHOD: Epidemiologically based survey. Over a 3-year period individuals with psychosis on first contact with services were identified and diagnosed according to ICD-10 criteria. RESULTS: In total, 558 individuals with first-episode psychosis were identified during 3,077,555 person-years at risk. The annual incidence rate per 100,000 was 18.1 for all psychoses, 14.3 for non-affective psychoses and 3.8 for affective psychoses. The rate for all psychoses was higher in young people aged 20-29 (incidence rate ratio (IRR) = 4.18, 95% CI 2.77-6.30), immigrants (IRR = 2.26, 95% CI 1.85-2.75) and those living in the most deprived areas (IRR = 2.09, 95% CI 1.54-2.85). CONCLUSIONS: The incidence rate in our study area was lower than that found in other European and North American studies and provides new insights into the factors that may increase and/or decrease risk for developing psychosis.

Positive symptoms in first-episode psychosis patients experiencing low maternal care and stressful life events: a pilot study to explore the role of the COMT gene.

COMT Val(158)Met moderates the effect of stress on psychotic symptoms. Exposure to stress is also associated with mesolimbic dopamine release in individuals experiencing low maternal care. We therefore test the hypothesis that recent stressful life events are associated with more severe positive symptoms (associated with mesolimbic dopamine release) in first-episode psychosis (FEP) patients who experienced low maternal care during childhood. We hypothesized that COMT Val(158)Met moderates this association. A total of 149 FEP patients recruited within the Psychosis Incident Cohort Outcome Study (PICOS) participated in the present study. Maternal care was assessed by the Parental Bonding Instrument (PBI), stressful life events were collected by the List of Events Scale and positive symptoms were assessed by the Positive and Negative Syndrome Scale (PANSS). We found that low maternal care and recent stressful life events were associated with higher level of positive symptoms at the onset (analysis of variance [ANOVA], p = 0.012), and that patients who were also homozygotes for the COMT Val(158) allele had the highest level of positive symptoms (ANOVA, p = 0.024). Low maternal care and severe stressful life events may contribute to a symptomatology characterized by more severe positive symptoms at the onset, possibly due to an increased mesolimbic dopamine release. Homozygosity for the COMT Val(158) allele seems to confer a biological predisposition to the stress-related hyperactivity of the mesolimbic dopaminergic system. The data imply that the mesolimbic dopaminergic system is involved in the mediation/modulation of the effect of stressful events on the vulnerability for psychosis.

Community mental health care in the future: nine proposals.

The aim of this article was to put community psychiatry into a longitudinal and global perspective and to try to look into the future. Specifically, we set out the following nine proposals:1. Central and regional government should measure the treated percentage of people with mental illness (coverage) and set specific targets to increase coverage over set time periods.2. Health care services need to recognize the far lower life expectancy among people with mental disorders and develop and evaluate new methods to reduce this health disparity.3. Mental health services should provide specific modules to reduce stigma and discrimination experienced by people with mental illness.4. Mental health staff should provide care that service users (and their family members) find accessible and acceptable.5. Mental health care should consist of a careful balance of hospital and community care, with most care provided at or near people's homes.6. Mental health planners, both in times of economic growth and recession, should invest in treatments known to be effective and disinvest from treatments known to be ineffective or even harmful.7. Mental health staff and service users should develop and evaluate methods to improve shared decision making.8. Health care practitioners (of western and nonwestern traditions) should take practical steps to see each other as partners in an integrated system that increases the total amount of mental health care available, while ensuring that only effective and acceptable treatments are provided.9. Mental health services should develop dedicated programs for recovery: this implies that staff understand an individual's personal recovery goals and fully support his/her achievement.

Cancer mortality among psychiatric patients treated in a community-based system of care: a 25-year case register study.

PURPOSE: Cancer mortality data allow assessing, at the same time, the risk of developing the disease and the quality of care provided to patients after the oncologic diagnosis. This study explores the risk of death caused by a single tumor site in a psychiatric population treated in a community-based psychiatric service. METHODS: All patients with an ICD-10 psychiatric diagnosis, seeking care in 1982-2006 (25 years), were included. Data were drawn from the South Verona Psychiatric Case Register (PCR). Mortality and cause of death were ascertained using different procedures and sources. Standardized mortality ratios (SMRs) were used to compare the observed number of deaths with the expected number using as reference a population in the Veneto region. RESULTS: Having been admitted to the hospital (SMR = 1.32), having a short interval from registration (1.52), having a diagnosis of alcoholism (2.03), and being a middle-aged male (1.83) were factors showing an increased risk of death from cancer. Increased SMRs were found for cancer of the oral cavity (22.93), lymphoma, leukemias, Hodgkin's lymphoma (8.01), and central nervous system (CNS) and cranial nerve tumors (4.75). The SMR decreased for stomach tumors (0.49). Patients with alcoholism (5.90 for larynx), affective disorders (20.00 for lymphomas), and personality disorders (28.00 for SNC) were found to be exposed to a high risk of cancer death in specific sites. CONCLUSIONS: Psychiatric patients showed different patterns of site-specific cancer mortality when compared with the general population. The 20-fold higher risk of dying from hematological neoplasms needs further investigation. Chronic use of phenothiazines could be involved in the relative protection from stomach and prostate cancer found in psychiatric patients.

The balanced care model: the case for both hospital- and community-based mental healthcare.

The balanced care model proposes that a comprehensive mental health system needs to include both community- and hospital-based care. The model is based on a structured review of scientific evidence, and is also informed by the experience of experts active in mental health system change in many countries worldwide.

Aripiprazole versus haloperidol in combination with clozapine for treatment-resistant schizophrenia: a 12-month, randomized, naturalistic trial.

BACKGROUND: Long-term studies for patients with resistant schizophrenia are necessary to assess the effectiveness of combination strategies on persisting positive symptoms. AIMS AND METHODS: This multicenter, naturalistic, randomized, superiority study (ClinicalTrials.gov identifier: NCT00395915) aimed to compare clinical efficacy and tolerability of haloperidol versus aripiprazole as combination treatment with clozapine in patients with resistant schizophrenia. RESULTS: One hundred six patients were followed up for 12 months. After 12 months, the proportion of patients who discontinued treatment was not significantly different between aripiprazole and haloperidol (37% vs 28%, respectively; P = 0.431). The change in the Brief Psychiatric Rating Scale score was similar in the aripiprazole and haloperidol groups (-7.0 vs -7.9, respectively; P = 0.389), whereas the tolerability total score decreased significantly more in the aripiprazole group (-7.2 vs -2.3; P = 0.008). CONCLUSIONS: While the effectiveness of clozapine augmentation with a second antipsychotic agent is not clearly demonstrated yet, results from this study suggest that augmentation with aripiprazole offers no substantial benefit over haloperidol in efficacy. Aripiprazole was perceived more tolerable than haloperidol, but it is uncertain how this finding may translate into the real world of clinical practice.

Cost-effectiveness of adherence therapy versus health education for people with schizophrenia: randomised controlled trial in four European countries.

BACKGROUND: Non-adherence to anti-psychotics is common, expensive and affects recovery. We therefore examine the cost-effectiveness of adherence therapy for people with schizophrenia by multi-centre randomised trial in Amsterdam, London, Leipzig and Verona. METHODS: Participants received 8 sessions of adherence therapy or health education. We measured lost productivity and use of health/social care, criminal justice system and informal care at baseline and one year to estimate and compare mean total costs from health/social care and societal perspectives. Outcomes were the Short Form 36 (SF-36) mental component score (MCS) and quality-adjusted life years (QALYs) gained (SF-36 and EuroQoL 5 dimension (EQ5D)). Cost-effectiveness was examined for all cost and outcome combinations using cost-effectiveness acceptability curves (CEACs). RESULTS: 409 participants were recruited. There were no cost or outcome differences between adherence therapy and health education. The probability of adherence therapy being cost-effective compared to health education was between 0.3 and 0.6 for the six cost-outcome combinations at the willingness to pay thresholds we examined. CONCLUSIONS: Adherence therapy appears equivalent to health education. It is unclear whether it would have performed differently against a treatment as usual control, whether such an intervention can impact on quality of life in the short-term, or whether it is likely to be cost-effective in some sites but not others. TRIAL REGISTRATION: Trial registration: Current Controlled Trials ISRCTN01816159.

Thalamic-insular dysconnectivity in schizophrenia: evidence from structural equation modeling.

Structural and functional studies have shown that schizophrenia is often associated with frontolimbic abnormalities in the prefrontal and mediotemporal regions. It is still unclear, however, if such dysfunctional interaction extends as well to relay regions such as the thalamus and the anterior insula. Here, we measured gray matter volumes of five right-hemisphere regions in 68 patients with schizophrenia and 77 matched healthy subjects. The regions were amygdala, thalamus, and entorhinal cortex (identified as anomalous by prior studies on the same population) and dorsolateral prefrontal cortex and anterior insula (isolated by voxel-based morphometry analysis). We used structural equation modeling and found altered path coefficients connecting the thalamus to the anterior insula, the amygdala to the DLPFC, and the entorhinal cortex to the DLPFC. In particular, patients exhibited a stronger thalamus-insular connection than healthy controls. Instead, controls showed positive entorhinal-DLPFC and negative amygdalar-DLPFC connections, both of which were absent in the clinical population. Our data provide evidence that schizophrenia is characterized by an impaired right-hemisphere network, in which intrahemispheric communication involving relay structures may play a major role in sustaining the pathophysiology of the disease.

Is neuregulin 1 involved in determining cerebral volumes in schizophrenia? Preliminary results showing a decrease in superior temporal gyrus volume.

BACKGROUND/AIMS: Reduced left superior temporal gyrus (STG) volume is one of the most replicated imaging findings in schizophrenia. However, it remains unclear whether genes play any role in our understanding of such structural alteration. It has been proposed that Neuregulin 1 (NRG1) might be a promising gene involved in schizophrenia, because of its role in neurodevelopment and neuroplasticity. In this study, the association between NRG1 and STG anatomy in patients with schizophrenia was explored for the first time. METHODS: We investigated a 1-year treated prevalence cohort of patients with schizophrenia in contact with the South Verona Community-Based Mental Health Service. A blood sample was collected for DNA extraction and brain structure was assessed with an MRI scan. A total of 27 subjects with schizophrenia underwent both assessments and were included in the study. RESULTS: We investigated the association between the polymorphism SNP8NRG222662 (rs4623364) of NRG1 and volume of the STG. We found that patients homozygous for the C allele had reduced left STG gray and white matter volumes in comparison to those homozygous for the G allele (p < 0.01 and p < 0.001, respectively). CONCLUSIONS: This exploratory study suggests that NRG1 may be involved in determining STG size in schizophrenia, and may play a role in the neurogenetic basis of the language disturbances seen in this disorder. However, due to our small sample size, the results should be regarded as preliminary and replicated in a larger sample.

State of psychiatry in Italy 35 years after psychiatric reform. A critical appraisal of national and local data.

Thirty-four years have elapsed since the passing of the Italian Law 180, the reform law that marked the transition from a hospital-based system of care to a model of community psychiatry that was designed to be an alternative to, rather than to complement, the old hospital-centred services. The main principle of Law 180 is that psychiatric patients have the right to be treated the same way as patients with other diseases and only voluntary treatments are allowed, with a few exceptions that are strictly regulated. The main features and consequences of the Italian reform are initially reviewed; national and local level experiences and epidemiological data are then analysed in order to highlight and disentangle the 'active ingredients' of the Italian experience. A public health attitude with the capacity to network good practice in service organization by giving voice to successful experiences and promoting health service research, apart from some local services, is still generally lacking. Furthermore, it is still difficult to provide an evidence-based reply to the question: can à l'Italienne community-care be exported elsewhere?

Adverse effects of antipsychotic drugs: survey of doctors' versus patients' perspective.

AIMS: Almost no data are available on whether patients and doctors have similar or dissimilar opinions on the presence and level of distress due to antipsychotic adverse effects. The aim of this survey is to compare doctors' versus patients' perspective on the presence and level of distress due to antipsychotic adverse effects in a sample of patients under the care of the South-Verona mental health services. METHODS: All patients exposed to antipsychotic drugs during a census period of 6 months were identified. For each included subject, socio-demographic, clinical and treatment data were extracted. Patients' perspective on antipsychotic adverse effects was measured by means of the Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS). The LUNSERS was similarly employed to measure doctors' perspective on antipsychotic adverse effects. RESULTS: During the recruitment period, 243 patients taking antipsychotic drugs were enrolled. The correlation between the total LUNSERS score reported by patients and doctors was very low (correlation coefficient 0.22, 95% confidence interval 0.15-0.30). On average, patients perceived more adverse effects and with a significant higher distress than doctors. Multivariate analyses found no factors simultaneously associated with both patient and doctor ratings of adverse effects. CONCLUSION: Our study suggests that doctors, researchers and health care providers should increasingly consider patient and doctor perspectives as two complementary dimensions that may provide different insights in the evaluation of antipsychotic drugs. Integrating different points of view may represent a way to develop a better therapeutic alliance that might decrease the likelihood of nonadherence.

White matter microstructure alterations in bipolar disorder.

Genetic, neuropathological and magnetic resonance imaging findings support the presence of diffuse white matter cytoarchitectural disruption in bipolar disorder. In this study, diffusion-weighted imaging (DWI) was applied to study cortical white matter microstructure organisation in 24 patients with DSM-IV bipolar disorder and 35 matched normal controls. DWI images were obtained using a 1.5 Tesla scanner and apparent diffusion coefficient (ADC) values were determined over regions of interest placed, bilaterally, in the frontal, temporal, parietal, and occipital white matter. Significantly increased ADC values were found in bipolar patients with respect to normal controls in the right temporal lobe, left parietal lobe and bilateral occipital lobes. ADC values did not associate significantly with age or with clinical variables (p>0.05). Diffuse cortical white matter alterations on DWI in bipolar disorder denote widespread disruption of white matter integrity and may be due to altered myelination and/or axonal integrity.

Aripiprazole versus haloperidol in combination with clozapine for treatment-resistant schizophrenia in routine clinical care: a randomized, controlled trial.

This multisite study was conducted to compare the efficacy and tolerability of combination treatment with clozapine plus aripiprazole versus combination treatment with clozapine plus haloperidol in patients with schizophrenia who do not have an optimal response to clozapine. Patients continued to take clozapine and were randomly assigned to receive daily augmentation with aripiprazole or haloperidol. Physicians prescribed the allocated treatments according to usual clinical care. Withdrawal from allocated treatment within 3 months was the primary outcome. Secondary outcomes included severity of symptoms on the Brief Psychiatric Rating Scale and antipsychotic subjective tolerability on the Liverpool University Neuroleptic Side Effect Rating Scale. A total of 106 patients with schizophrenia were randomly assigned to treatment. After 3 months, we found no difference in the proportion of patients who discontinued treatment between the aripiprazole and haloperidol groups (13.2% vs 15.1%, P = 0.780). The 3-month change of the Brief Psychiatric Rating Scale total score was similar in the aripiprazole and haloperidol groups (-5.9 vs -4.4 points, P = 0.523), whereas the 3-month decrease of the Liverpool University Neuroleptic Side Effect Rating Scale total score was significantly higher in the aripiprazole group than in the haloperidol group (-7.4 vs -2.0 points, P = 0.006). These results suggest that augmentation of clozapine with aripiprazole offers no benefit with regard to treatment withdrawal and overall symptoms in schizophrenia compared with augmentation with haloperidol. However, an advantage in the perception of adverse effects with aripiprazole treatment may be meaningful for patients.

The impact of schizophrenia on frontal perfusion parameters: a DSC-MRI study.

We performed a dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) analysis to study the role of the demographic/clinical information on perfusion parameters between patients with schizophrenia and normal control subjects. 39 schizophrenia patients and 27 normal controls were studied with a Siemens 1.5T magnet. PWI images were obtained following intravenous injection of paramagnetic contrast agent (gadolinium-DTPA). For each perfusion parameter, i.e. relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), mean transit time (MTT) and time-to-peak (TTP), the best predictor model was computed in left and right frontal cortex following a stepwise strategy. First of all, a linear model, including all the sociodemographic information and clinical variables as predictors was computed. At each step, the least significant predictor was excluded and a new linear model was evaluated until all predictors were excluded. Then, the best predictor model was selected based on the F statistic value and on the p value. The models for the rCBF and the rCBV both in the left and right frontal cortex were estimated independently from each other, and the best models contained the same predictors, i.e. clinical state, age, and length of illness. No significant models were obtained for the MTT and the TTP. This study showed a decrease in rCBF and rCBV frontal cortex values in subject affected by schizophrenia. Future DSC-MRI studies should further investigate the role of cerebral perfusion for the pathophysiology of the disease by recruiting first-episode patients and by considering cerebellar, parietal and temporal regions.

Investigation of shared genetic effects for psychotic and obsessive symptoms in young adult twins.

Genetic and environmental architecture of psychotic and obsessive symptoms are not completely elucidated. This study estimated for these symptoms (i) the genetic and environmental components, (ii) the within-individual association, and (iii) the extent to which this association originates from common genetic and environmental factors. Young adult twins (N=701) from the population-based Italian Twin Register were assessed for psychotic and obsessive-compulsive symptoms by using the Symptom Check List (SCL-90). Multivariate Cholesky models were fitted by the Mx statistical program. No previous study used this design to examine the same dimensions. The best-fitting model included additive genetic and nonshared environmental components, each accounting for about half of total variance in the symptoms. Genetic influences on the different symptoms overlapped considerably (r(g)=0.81 to 0.99). Phenotypic correlations of psychotic symptoms and of psychotic with obsessive symptoms were high (r=0.61 to 0.76), with 53% to 69% explained by shared genetic effects. This study shows substantial genetic influence on psychotic and obsessive symptoms, and indicates that their co-occurrence may be due to genetic factors to a greater extent than to environmental effects. These results encourage the search for genetic and environmental factors underlying the covariance between different psychotic traits as well as between psychotic and obsessive traits.

Cerebellar and lobar blood flow in schizophrenia: a perfusion weighted imaging study.

It is still not clear whether brain hemodynamics plays a role in the functional and structural alterations in schizophrenia, since prior imaging studies showed conflicting findings. In this study we non-invasively explored cerebral and cerebellar lobe perfusion in the largest population of participants with schizophrenia thus far studied with perfusion-weighted imaging (PWI). Forty-seven participants affected by schizophrenia and 29 normal controls were recruited. PWI images were acquired following the intravenous injection of a paramagnetic contrast agent. Regional cerebral blood volume (CBV), blood flow (rCBF), and mean transit time (MTT) were obtained with the block-Circulant Singular Value Decomposition (cSVD) for frontal, temporal, parietal, occipital, and cerebellar lobes, bilaterally. Perfusion parameters were separately obtained for both gray and white matter in each lobe. Subjects with schizophrenia showed no significant differences in perfusion parameters when compared with controls. Interestingly, inverse correlations between age at onset and occipital, frontal and cerebellar MTT and between length of illness and frontal CBV were found. Preserved cerebral and cerebellar perfusion in our chronic population may in part be due to the effects of antipsychotic treatment which may have normalized blood volume and flow. Hypoperfusion in relation to chronicity, particularly in the frontal lobe, has been observed in accordance with earlier studies using positron emission tomography.

How are caseload and service utilisation of psychiatric services influenced by distance? A geographical approach to the study of community-based mental health services.

INTRODUCTION: The aim of this study was to assess how the caseload and the utilisation of community-based mental health services is influenced by distance and to socioeconomic characteristics. METHODS: Spatial and statistical analyses were conducted with a sample of 12,347 patients, with ICD-10 psychiatric diagnosis, who had at least one contact with psychiatric services in Verona, Italy, between 2000 and 2006. Three types of mental health facility were considered: acute inpatient wards, outpatient clinics, and community mental health centres (CMHC). To measure distance and accessibility, the locations of static mental health facilities and patients' homes were geocoded. Data were organised in a spatial database, which included census blocks, catchment areas locations, road network graphs, patients' and facilities' locations. In order to calculate travel distances, patients' and facilities' locations were connected to the road network. Accessibility was modelled by using the Network Analyst Service Area Function and 13 Service Areas were created around all facility locations, by measuring distances along the street network. For the epidemiological analyses, patients and census block centroids were linked to the service areas by using spatial join techniques. Epidemiological and utilisation analyses were performed for each type of setting. RESULTS: The facilities were not equally located in the catchment areas. Of particular significance, rural areas appear to be poorly served by mental health services. The distance decay effect exists, with different trends for the three types of facility. The caseload (number of patients using services) decreased with increasing distance; at a distance of 10 km, there was a decrease of 80, 60 and 85%, respectively, for CMHCs, inpatients wards and outpatients clinics. From the Poisson regression models, distance was significantly correlated (p value < 0.0001) with service use. Also univariate analyses showed a statistically significant association between distance and caseload for each type of setting (p value < 0.05), with a decrease in service use for each service area increase in distance (1.5% for acute inpatient wards, 2.0% for CMHC, and 2.1% outpatient clinics). By adding other predictors in the Poisson regression models, these percentages increased. CONCLUSIONS: Further studies are needed to evaluate the influence of other factors, such as environmental variables, that may influence the use of mental health services.

Comparative efficacy and acceptability of 12 new-generation antidepressants: a multiple-treatments meta-analysis.

BACKGROUND: Conventional meta-analyses have shown inconsistent results for efficacy of second-generation antidepressants. We therefore did a multiple-treatments meta-analysis, which accounts for both direct and indirect comparisons, to assess the effects of 12 new-generation antidepressants on major depression. METHODS: We systematically reviewed 117 randomised controlled trials (25 928 participants) from 1991 up to Nov 30, 2007, which compared any of the following antidepressants at therapeutic dose range for the acute treatment of unipolar major depression in adults: bupropion, citalopram, duloxetine, escitalopram, fluoxetine, fluvoxamine, milnacipran, mirtazapine, paroxetine, reboxetine, sertraline, and venlafaxine. The main outcomes were the proportion of patients who responded to or dropped out of the allocated treatment. Analysis was done on an intention-to-treat basis. FINDINGS: Mirtazapine, escitalopram, venlafaxine, and sertraline were significantly more efficacious than duloxetine (odds ratios [OR] 1.39, 1.33, 1.30 and 1.27, respectively), fluoxetine (1.37, 1.32, 1.28, and 1.25, respectively), fluvoxamine (1.41, 1.35, 1.30, and 1.27, respectively), paroxetine (1.35, 1.30, 1.27, and 1.22, respectively), and reboxetine (2.03, 1.95, 1.89, and 1.85, respectively). Reboxetine was significantly less efficacious than all the other antidepressants tested. Escitalopram and sertraline showed the best profile of acceptability, leading to significantly fewer discontinuations than did duloxetine, fluvoxamine, paroxetine, reboxetine, and venlafaxine. INTERPRETATION: Clinically important differences exist between commonly prescribed antidepressants for both efficacy and acceptability in favour of escitalopram and sertraline. Sertraline might be the best choice when starting treatment for moderate to severe major depression in adults because it has the most favourable balance between benefits, acceptability, and acquisition cost.

Laterality effects in schizophrenia and bipolar disorder.

There are numerous reports in the literature of lateralised structural cerebral abnormalities and alterations of the corpus callosum in the major psychoses. In the light of these findings the purpose of this study was to directly compare hemispheric differences and callosal interhemispheric transmission (IT) in schizophrenia and bipolar disorder. To do that we tested schizophrenic (SCZ), bipolar disorder (BD) patients and controls in a simple manual reaction time (RT) task with lateralised visual stimuli (Poffenberger paradigm) which enables one to test both laterality effects and IT time. We found an overall slowing of responses with the right hand in schizophrenics but not in bipolar patients, who, like controls, showed no hand differences. This selective slowing down of the right hand is likely to be related to abnormalities of intrahemispheric cortico-cortical connections in the left hemisphere. In contrast, IT time was similar in SCZ and BD patients and did not differ with respect to controls. Two are the novel findings of the present study: first both SZC and BD share a normal IT of visuomotor information despite the presence of callosal abnormalities. Second, an impairment of intrahemispheric left hemispheric processing is present only in SCZ patients. This represents a potentially important clue to a further understanding of the pathogenetic differences between the two major psychoses.