An ‘ethnic’ or ‘group’ density effect in psychosis has been observed, whereby the risk of psychosis in minority group individuals is inversely related to neighbourhood-level proportions of others belonging to the same group. However, there is conflicting evidence over whether this effect differs between minority groups and limited investigation into other moderators.

To conduct a comprehensive systematic review and meta-analysis of the group density effect in psychosis and examine moderators.

Four databases were systematically searched. A narrative review was conducted and a three-level meta-analysis was performed. The potential moderating effect of crudely and specifically defined minority groups was assessed. Country, time, area size and whether studies used clinical or non-clinical outcomes were also tested as moderators.

Thirty-two studies were included in the narrative review and ten in the meta-analysis. A 10 percentage-point decrease in own-group density was associated with a 20% increase in psychosis risk (OR = 1.20, 95% CI 1.09−1.32, P < 0.001). This was moderated by crudely defined minority groups (F6,68 = 6.86, P < 0.001), with the strongest associations observed in Black populations, followed by a White Other sample. Greater heterogeneity was observed when specific minority groups were assessed (F25,49 = 7.26, P < 0.001).

This is the first review to provide meta-analytic evidence that the risk of psychosis posed by lower own-group density varies across minority groups, with the strongest associations observed in Black individuals. Heterogeneity in effect sizes may reflect distinctive social experiences of specific minority groups. Potential mechanisms are discussed, along with the implications of findings and suggestions for future research.

Language use is often disrupted in patients with schizophrenia; novel computational approaches may provide new insights.

To test word use patterns as markers of the perceptual, cognitive and social experiences characteristic of schizophrenia.

Word counting software was applied to first-person accounts of schizophrenia and mood disorder.

More third-person plural pronouns (‘they’) and fewer first-person singular pronouns (‘I’) were used in schizophrenia than mood disorder accounts. Schizophrenia accounts included fewer words related to the body and ingestion, and more related to religion. Perceptual and causal language were negatively correlated in schizophrenia accounts but positively correlated in mood disorder accounts.

Differences in pronouns suggest decreased self-focus or perhaps even an understanding of self as other in schizophrenia. Differences in how perceptual and causal words are correlated suggest that long-held delusions represent a decreased coupling of explanations with sensory experience over time.

The community treatment order (CTO) is the legal framework by which people in the community are compelled to accept treatment. Both antipsychotic long-acting injections (LAIs) and CTOs are used to address treatment non-adherence.

To investigate the relationship between CTOs and LAI use in patients with schizophrenia.

Prescribing, demographic and CTO data were collected for patients from four community mental health clinics in Melbourne, Australia, in 1998 and 2002.

Against a background of increasing use of oral second-generation antipsychotic (SGA) medication and decreasing use of LAIs, the rates of CTO implementation doubled from 13% to 26% of patients with schizophrenia between 1998 and 2002. Proportionally more patients with a CTO are prescribed LAIs rather than oral SGAs.

The relationship between receiving an LAI and being subject to a CTO is significant, and reflects the consideration given to enhancing adherence in a community mental health setting.

The retina contains high concentrations of dopamine. We previously reported that recently withdrawn cocaine-dependent patients had significantly reduced blue cone b wave amplitude responses on the electroretinogram (ERG). In this study we wished to examine if there was a relationship between cocaine craving and reduced blue cone b wave ERG responses.

A series of 14 recently withdrawn cocaine-dependent patients completed a 45-item cocaine craving questionnaire shortly before the ERG.

Cocaine dependent patients who had a reduced (<0.5 microvolts) blue cone b wave ERG response had significantly higher cocaine craving scores than patients without a reduced blue cone ERG response. There was also a significant negative correlation between blue cone b wave amplitude responses and scores on the cocaine craving questionnaire.

A reduced blue cone b wave ERG response may identify recently withdrawn cocaine-dependent patients with biological dysregulation and increased cocaine craving.

Cross-national research into the care of people with severe mental illnesses is hampered by a lack of standardised measures. The European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study is a European Union funded project within the BIOMED-2 programme. The project aims to develop standardised instruments to facilitate future cross-national research.

To describe the aims, outcome measures, study sites and patient samples of the EPSILON Study.

See companion papers in this supplement.

Second-generation antipsychotics may have few advantages over older, cheaper drugs, except for possibly reduced risk of tardive dyskinesia.

To evaluate the cost-effectiveness of second-generation antipsychotics with regard to reducing tardive dyskinesia.

Literature was reviewed on risk of tardive dyskinesia with second-generation antipsychotics; on severity duration and impairment of tardive dyskinesia; and on the relationship of this disorder to quality of life and quality-adjusted life-years (QALYs). Diverse cost and benefit assumptions and of 1-year and 5-year planning horizons were examined in a deterministic sensitivity analysis.

Estimating 0.143 QALYs lost per case of severe tardive dyskinesia, 1-year cost-effectiveness estimates for second-generation antipsychotics ranged from $185 000 ($370 000) to $850 000 ($1.7 million) per QALY, and 5-year cumulative estimates ranged from $74 000 ($ 149 000) to $342 000 ($683 000) per QALY, all above the conventional policy threshold of $25 000 ($50 000).

Reduction of tardive dyskinesia with second-generation antipsychotics appears unlikely to meet standards for cost-effectiveness.

Hippocampal abnormalities have been demonstrated in schizophrenia. It is unclear whether these abnormalities worsen with age, and whether they affect cognition and function.

To determine whether hippocampal abnormalities in chronic schizophrenia are associated with age, cognition and socio-occupational function.

Using 3 T magnetic resonance imaging we scanned 100 persons aged 19–82 years: 51 were out-patients with stable schizophrenia at least 2 years after diagnosis and 49 were healthy volunteers matched for age and gender. Automated analysis was used to determine hippocampal volume and shape.

There were differential effects of age in the schizophrenia and control samples on total hippocampal volume (group×age interaction: F(1,95) = 6.57, P = 0.012), with steeper age-related reduction in the schizophrenia group. Three-dimensional shape analysis located the age-related deformations predominantly in the mid-body of the hippocampus. In the schizophrenia group similar patterns of morphometric abnormalities were correlated with impaired cognition and poorer socio-occupational function.

Hippocampal abnormalities are associated with age in people with chronic schizophrenia, with a steeper decline than in healthy individuals. These abnormalities are associated with cognitive and functional deficits, suggesting that hippocampal morphometry may be a biomarker for cognitive decline in older patients with schizophrenia.

Recent studies show that adverse life events have a significantly greater impact on depression onset for those with the s/s allele of the genotype for the 5-HT gene-linked promoter region. Research in genes related to risk of depression leads to the question of how this information is received by individuals.

To investigate factors related to the response to receiving one's own serotonin transporter genotype results.

Predictors of the impact of receiving individual genotype data were assessed in 128 participants in a study of gene–environment interaction in depression onset.

Two-thirds decided to learn their individual genotype results (receivers) and prior to disclosure this decision was associated with a perception of greater benefit from receipt of the information (P=0.001). Receivers completing the 2-week (n=76) and 3-month follow-up (n=78) generally reported feeling pleased with the information and having had a more positive experience than distress. However, distress was related to genotype, with those with the s/s allele being most affected.

There was high interest in, and satisfaction with, learning about one's serotonin transporter genotype. Participants appeared to understand that the gene conferred susceptibility to depression rather than a direct causal effect.