Mismatch negativity: Alterations in adults from the general population who report subclinical psychotic symptoms

BACKGROUND

Deficits of mismatch negativity (MMN) in schizophrenia and individuals at risk for psychosis have been replicated many times. Several studies have also demonstrated the occurrence of subclinical psychotic symptoms within the general population. However, none has yet investigated MMN in individuals from the general population who report subclinical psychotic symptoms.

METHODS

The MMN to duration-, frequency-, and intensity deviants was recorded in 217 nonclinical individuals classified into a control group (n=72) and three subclinical groups: paranoid (n=44), psychotic (n=51), and mixed paranoid-psychotic (n=50). Amplitudes of MMN at frontocentral electrodes were referenced to average. Based on a three-source model of MMN generation, we conducted an MMN source analysis and compared the amplitudes of surface electrodes and sources among groups.

RESULTS

We found no significant differences in MMN amplitudes of surface electrodes. However, significant differences in MMN generation among the four groups were revealed at the frontal source for duration-deviant stimuli (P=0.01). We also detected a trend-level difference (P=0.05) in MMN activity among those groups for frequency deviants at the frontal source.

CONCLUSIONS

Individuals from the general population who report psychotic symptoms are a heterogeneous group. However, alterations exist in their frontal MMN activity. This increased activity might be an indicator of more sensitive perception regarding changes in the environment for individuals with subclinical psychotic symptoms.

Brain correlates of verbal fluency in subthreshold psychosis assessed by functional near-infrared spectroscopy

The prevalence of subthreshold psychotic symptoms in the general population has gained increasing interest as a possible precursor of psychotic disorders. The goal of the present study was to evaluate whether neurobiological features of subthreshold psychotic symptoms can be detected using verbal fluency tasks and functional near-infrared spectroscopy (fNIRS). A large data set was obtained from the Zurich Program for Sustainable Development of Mental Health Services (ZInEP). Based on the SCL-90-R subscales 'Paranoid Ideation' and 'Psychoticism' a total sample of 188 subjects was assigned to four groups with different levels of subthreshold psychotic symptoms. All subjects completed a phonemic and semantic verbal fluency task while fNIRS was recorded over the prefrontal and temporal cortices. Results revealed larger hemodynamic (oxy-hemoglobin) responses to the phonemic and semantic conditions compared to the control condition over prefrontal and temporal cortices. Subjects with high subthreshold psychotic symptoms exhibited significantly reduced hemodynamic responses in both conditions compared to the control group. Further, connectivity between prefrontal and temporal cortices revealed significantly weaker patterns in subjects with high subthreshold psychotic symptoms compared to the control group, possibly indicating less incisive network connections associated with subthreshold psychotic symptoms. The present findings provide evidence that subthreshold forms of psychotic symptoms are associated with reduced hemodynamic responses and connectivity in prefrontal and temporal cortices during verbal fluency that can be identified using fNIRS.

Colon capsule endoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

PillCam colon capsule endoscopy (CCE) is an innovative noninvasive, and painless ingestible capsule technique that allows exploration of the colon without the need for sedation and gas insufflation. Although it is already available in European and other countries, the clinical indications for CCE as well as the reporting and work-up of detected findings have not yet been standardized. The aim of this evidence-based and consensus-based guideline, commissioned by the European Society of Gastrointestinal Endoscopy (ESGE) is to furnish healthcare providers with a comprehensive framework for potential implementation of this technique in a clinical setting.

Public awareness of risk factors and screening for colorectal cancer in Europe

Colorectal cancer (CRC) is the commonest site for malignancy in Europe. The Commissioner for Health wishes to promote screening for colorectal, breast and cervical cancer in Europe. The aim of this study was to assess public knowledge of CRC in Europe and likely take up of free screening. To this end 20710 members of the public from 21 European countries were interviewed by means of a regular survey amongst consumers (Omnibus survey) using 13 stem questions. Forty-eight per cent thought the population were at equal risk of CRC, only 57% were aware of age and 54% of family history as risk factors. Although 70% were aware of dietary factors, only 30% knew that lack of exercise might be a risk factor. Only 51% had knowledge of CRC screening but 75% were 'very', or 'quite interested, in taking up faecal occult blood (FOB) screening if offered free. Barriers to screening were lack of awareness of risk (31%), youth (22%) and an un-anaesthetic test (19%). There was a big cultural difference in willingness of the public to discuss bowel symptoms: there was a major barrier in Finland (91%), Britain (84%), Luxembourg (82%), Poland (81%) and Portugal (80%); less of a barrier in Spain (49%), Italy (44%) and Iceland (39%). In conclusion, the challenge of achieving high compliance for CRC screening must be a major objective amongst EU member states and non-aligned countries of Europe in the next decade, because it is known that the non-compliant group are those at greatest risk of death from CRC. This study has shown that awareness of CRC is low in Europe and that an educational programme will be essential to achieve high compliance for CRC screening as a means of reducing deaths from bowel cancer.