Investigation of the occurrence of psychotic symptoms in non-psychiatric population may help to identify population at risk of psychosis. The aim of our study was to find out lifetime and current prevalence of psychotic symptoms in the general population of the Czech Republic. Study sample consisted of a stratified population. All participants were administered the Psychosis Screening Questionnaire and the data on psychiatric treatment and diagnosis according to the M.I.N.I. were recorded. In total, 3244 subjects responded (48.1% males and 51.9% females). The most frequently reported symptom was paranoia (7.7%), followed by hypomania (6.2%), strange experiences (5.2%), thought insertion (3.8%), and hallucinations (1.7%). Lifetime prevalence of minimum 1 psychotic symptom was 17.9%. The highest proportion of responders reported only one symptom (13.5%). Significantly more males than females experienced paranoia (p=0.002). In the subset of individuals with a history of at least one psychotic symptom, 70.6% never visited a psychiatrist, 78.9% did not meet diagnostic criteria of psychotic disorder according to the M.I.N.I., and 67.0% failed to have any psychiatric diagnosis at all. The results suggest a high frequency of psychotic experience among the ethnically homogeneous Czech population. Only the longitudinal follow-up could confirm whether the symptomatic subjects are at risk of development of psychotic disorder. More likely, our findings support a hypothesis of the presence of psychiatric symptoms in the general population as a continuum of psychotic spectrum, from normality and sanity through unique psychotic experiences to fully expressed illness.

Supported by the research project CNS 1M0517.

In the clinical practice, physicians are routinely asked to make decisions whether to initiate or continue antidepressant treatment in a situation where no safety data are available. As an example can serve pregnancy and breast-feeding, where controlled clinical trials provide little guidance. Females of fertile age are rarely included in the early phases of clinical testing, the Phase IIb and III trials have a standard provision to use a reliable contraception. Pregnancy during drug trial is considered as a ‘serious adverse event’ with subsequent study discontinuation. The reasons are not just ethical and legal but also marketing, the drug manufacturers fear to have their products associated with potentially grave side effects, such as malformations. Drug treatment in pregnancy and lactation thus pose a highly relevant clinical problem that cannot be addressed in controlled trials. Excessive concerns of negative consequences could erroneously result in generalizing recommendation not to get pregnant or to abort existing pregnancy. However, fetus may be already exposed to drugs early in the first trimester during frequently unplanned pregnancies; in addition, recent epidemiological data indicate increasing consumption of psychotropics, including antidepressants, by pregnant women. Psychiatrists have to weigh the known risks of treatment discontinuation versus potential risks for the fetus and infant. They should also consider whether alternative non-pharmacological interventions (psychotherapy, ECT, rTMS) are accessible or effective. The only available safety data on antidepressants come from animal studies, epidemiological trials, drug registries, case series, anecdotal case vignettes and clinical observations.

Supported by the research project MZ0PCP2005.

Computer programs are used in rehabilitation of cognitive deficit in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) can directly affect cortical excitability and metabolism of prefrontal lobe and subsequently affect cognition. The objective of our study was to investigate augmentation of cognitive rehabilitation in schizophrenia with rTMS. Study subjects were stabilized patients with DSM-IV diagnosis of schizophrenia, treated with second-generation antipsychotics, except for clozapine (total N=34). Study with rTMS was double-blind, randomized, placebo-controlled, with 2 parallel arms. All subjects participated in eight-week computer-assisted cognitive training, during first 2 weeks Group 1 (N=8) received rTMS and Group 2 (N=8) inactive sham stimulation. Patients who refused stimulation participated in rehabilitation program only. Data were assessed fo the totatl study sample and for each group separately. The results showed that computer-assisted cognitive training significantly improved severity of cognitive deficit in schizophrenia in many domains, especially executive functions: attention shift – flexibility, attention control, and working memory. The output was faster, more precise, and more reliable. We did not detect to effect of rTMS on the change of cognition, there was no significant difference between active and sham stimulation. This finding can be explained by a significantly lower initial score in Raven test found in actively stimulated group or by a smaller sample size in a double-blind study. The study confirmed efficacy of computer-assisted rehabilitation in remediation of cognitive deficit in schizophrenia.

Supported by the projects IGA MZ CR NF7571-3 and MSMT CR CNS 1M0517

Dysfunction of the serotonin system has been implicated in schizophrenia. 5-HT1A and 5-HT2A serotonin receptors are involved in the action of antipsychotic drugs. A common functional polymorphism (rs6295) in the promoter region of the human 5-HT1A receptor gene has been reported. This polymorphism may be useful in identifying psychopathology and phenotypic characteristics associated with altered function of the human 5-HT1A receptor.

The aim of this study was to determine whether genetic variants for these receptor influence the functional morphological characteristics of brain in schizophrenia.

63 patients with schizophrenia were genotyped for the functional variant in the promoter region of 5-HT1A receptor (rs6295) and for polymorphisms for 5-HT2A (rs6313) and serotonin transporter-SERT (rs4795541). The subjects were investigated by 18fluoro-deoxyglucose (18FDG) positron emission tomography (PET) in the resting state, magnetic resonance imaging (MR) and functional magnetic resonance (fMR) with 2-back test activation paradigm. Voxel-based-morphometry (VBM) was used to detect the differences in the density of grey and white matter. The neuroimaging data were treated by the use Statistical Parametric Mapping (SPM5) with genetic variants as the factor.

The polymorphism in 5-HT1A receptor was associated with the functional morphometric characteristics in cortical regions in projection areas of serotonergic system.

Our findings identify an important genetic factor predicting functional and structural characteristics in schizophrenia. Future research would test the role of HT1A polymorphism in the interaction with 5HT2A and SERT on morphological characteristics within the context of antipsychotic effects.

This research was supported by grant NR9324 (IGA MZCR) and by the project 1M0517 (MSMT).

Progress in neuroimaging contributed greatly to the schizophrenia research, including investigation of the etiological factors. We tested the hypothesis that lack of the normal asymmetry of language activation is familial and that it can be found in both schizophrenic and non-schizophrenic family members. In particular, we wanted to know whether relatives who are supposed to be transmitting liability to the illness also demonstrate the loss of asymmetry of language activation. We studied 5 families with at least two members affected with schizophrenia. Functional imaging (fMRI) was used to study cortical activation during a verbal task in Broca's area and its contralateral homologue in subjects with schizophrenia and their both parents who never manifested any psychotic symptoms but one of them had mother or father with schizophrenia. Schizophrenia patients showed lack of asymmetry of language activation. Parents without schizophrenia among their elderly relatives showed normal asymmetry of language activation. Three of parents who supposedly transmit liability to the illness demonstrated the loss of asymmetry of language activation. Our results suggest that lack of the normal asymmetry of language activation could be one of the inherited etiological factors of schizophrenia.

This work was supported by the research project of the Czech Ministry of Education, CNS 1M0517.

The hydrological ice-sheet basin draining into the Tasersiaq lake, West Greenland (66°13’ N, 50°30’W), was delineated, first using standard digital elevation models (DEMs) for ice-sheet surface and bedrock, and subsequently using a new high-resolution dataset, with a surface DEM derived from repeat-track interferometric synthetic aperture radar (SAR) and a bedrock topography derived from an airborne 60 MHz ice-penetrating radar. The extent of the delineation was calculated from a water-pressure potential as a function of the ice-sheet surface and bedrock elevations and a hydraulic factor k describing the relative importance of the potential of the ice overburden pressure compared to the bedrock topography. Themeltwater run-off for the basin delineations was modelled with an energy-balance model calibrated with observed ice-sheet ablation and compared to a 25 year time series of measured basin run-off. The standard DEMs were found to be inadequate for delineation purposes, whereas delineations from high-resolution data were found to be very sensitive to changes in k in a non-linear way, causing a factor 5 change of basin area, corresponding to a doubling of the modelled runoff. The 50% standard deviation of the measured basin run-off could thus be explained by small year-to-year variations of the k-factor.

Assuming a channelized drainage system in steady state, we investigate the influence of enhanced surface melting on the water pressure in subglacial channels, compared to that of changes in conduit geometry, ice rheology and catchment variations. The analysis is carried out for a specific part of the western Greenland ice-sheet margin between 66° N and 66°30′N using new high-resolution digital elevation models of the subglacial topography and the ice-sheet surface, based on an airborne ice-penetrating radar survey in 2003 and satellite repeat-track interferometric synthetic aperture radar analysis of European Remote-sensing Satellite 1 and 2 (ERS-1/-2) imagery, respectively. The water pressure is calculated up-glacier along a likely subglacial channel at distances of 1, 5 and 9 km from the outlet at the ice margin, using a modified version of Röthlisberger’s equation. Our results show that for the margin of the western Greenland ice sheet, the water pressure in subglacial channels is not sensitive to realistic variations in catchment size and mean surface water input compared to small changes in conduit geometry and ice rheology.

Site measurements were collected at Mount John University Observatory in 2005 and 2007 using a purpose-built scintillation detection and ranging system. C2N(h) profiling indicates a weak layer located at 12–14 km above sea level and strong low altitude turbulence extending up to 5 km. During calm weather conditions, an additional layer was detected at 6–8 km above sea level. V(h) profiling suggests that tropopause layer velocities are nominally 12–30m s−1, and near-ground velocities range between 2 and 20m s−1, dependent on weather. Little seasonal variation was detected in either C2N(h) and V(h) profiles. The average coherence length, r0, was found to be 7±1 cm for the full profile at a wavelength of 589 nm. The average isoplanatic angle, θ0, was 1.0±0.1 arcsec. The mean turbulence altitude, , was found to be 2.0±0.7 km above sea level. No average in the Greenwood frequency, fG, could be established due to the gaps present in the V(h) profiles obtained. A modified Hufnagel-Valley model was developed to describe the C2N(h) profiles at Mount John, which estimates r0 at 6 cm and θ0 at 0.9 arcsec. A series of V(h) models were developed, based on the Greenwood wind model with an additional peak located at low altitudes. Using the C2N(h) model and the suggested V(h) model for moderate ground wind speeds, fG is estimated at 79 Hz.