The neuropsychological basis of first-rank symptoms in schizophrenia (FRS) is still a matter of debate. Three broad explanatory models for FRS have been proposed, each arising from a different perspective: (i) medial temporal lobes pathology (Trimble, 1990); (ii) reduced cerebral lateralisation and interhemispheric transfer (Crow, 1997); and (iii) deficits in self-monitoring of intentions due to prefrontal inhibitory dysfunction (Frith et al, 2000). The aim of the study was to test whether patients with FRS would show deficits consistent with the above models.

A broad range of neuropsychological tests were administered to patients with and without FRS and to healthy controls, comprising tests of verbal and nonverbal memory, measures of cerebral lateralisation and interhemispheric communication, tasks of executive functioning, as well as tests of general cognitive abilities.

On some cognitive tests, results were supportive of theories advocating reduced cerebral lateralisation and self-monitoring impairment. An unexpected finding was that, on many cognitive tasks, the performance of patients with FRS was better than that of patients without FRS, and not significantly different from that of controls. These results could not be accounted for by demographic features or medication effects.

The current study may be the most comprehensive examination of neuropsychological performance in patients with FRS to date. Our results suggest that broad cognitive impairment is not a necessary correlate of FRS.

Familial risk for psychosis may interact with environmental risk factors.

We are studying a large birth cohort of children of mothers with psychotic disorders, themselves at high risk of developing a psychotic illness, to understand the developmental aetiology of psychotic illness.

Our aim is to examine whether exposure to environmental stressors in childhood, including timing of exposure, is a risk factor for psychotic illness, independent of familial liability. Specificity to maternal schizophrenia is explored.

We used record-linkage across state-wide registers (midwives, psychiatric, child protection and mortality, among others) to identify 15,486 offspring born in Western Australia 1980–2001 to mothers with a lifetime history of psychotic illness (case children) and compared them with 452,459 offspring born in the same period to mothers with no known psychiatric history (comparison children).

A total of 4.1% of case children had developed a psychotic illness compared to 1.1% of comparison children. Exposure to environmental risk factors including obstetric complications, aboriginality, lower socioeconomic status, discontinuity in parenting and childhood abuse significantly increased risk of psychotic illness in offspring. Length and age at time of discontinuity in parenting impacted on risk. At the same time, case children were also significantly more likely than comparison children to be at risk of experiencing these adverse life events.

Exposure to environmental stressors is associated with psychotic illness, and timing of exposure is important. However, children already at increased familial risk for psychotic illness are also at increased risk of experiencing these environmental stressors.

The authors have not supplied their declaration of competing interest.

There is increasing evidence for shared genetic susceptibility between schizophrenia and bipolar disorder. Although genetic variants only convey subtle increases in risk individually, their combination into a polygenic risk score constitutes a strong disease predictor.

To investigate whether schizophrenia and bipolar disorder polygenic risk scores can distinguish people with broadly defined psychosis and their unaffected relatives from controls.

Using the latest Psychiatric Genomics Consortium data, we calculated schizophrenia and bipolar disorder polygenic risk scores for 1168 people with psychosis, 552 unaffected relatives and 1472 controls.

Patients with broadly defined psychosis had dramatic increases in schizophrenia and bipolar polygenic risk scores, as did their relatives, albeit to a lesser degree. However, the accuracy of predictive models was modest.

Although polygenic risk scores are not ready for clinical use, it is hoped that as they are refined they could help towards risk reduction advice and early interventions for psychosis.

R.M.M. has received honoraria for lectures from Janssen, Lundbeck, Lilly, Otsuka and Sunovian.

A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.

This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.

The P300 amplitude and latency were not associated (regression coef. −0.06, 95% CI −0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10–0.28, p < 0.001). There was no evidence of associations between lateral ventricular volume and the other measures (all p > 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.

The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.

Schizotypal traits are considered a phenotypic-indicator of schizotypy, a latent personality organization reflecting a putative liability for psychosis. To date, no previous study has examined the comparability of factorial structures across samples originating from different countries and cultures. The main goal was to evaluate the factorial structure and reliability of the Schizotypal Personality Questionnaire (SPQ) scores by amalgamating data from studies conducted in 12 countries and across 21 sites.

The overall sample consisted of 27 001 participants (37.5% males, n = 4251 drawn from the general population). The mean age was 22.12 years (s.d. = 6.28, range 16–55 years). The SPQ was used. Confirmatory factor analysis (CFA) and Multilevel CFA (ML-CFA) were used to evaluate the factor structure underlying the SPQ scores.

At the SPQ item level, the nine factor and second-order factor models showed adequate goodness-of-fit. At the SPQ subscale level, three- and four-factor models displayed better goodness-of-fit indices than other CFA models. ML-CFA showed that the intraclass correlation coefficients values were lower than 0.106. The three-factor model showed adequate goodness of fit indices in multilevel analysis. The ordinal α coefficients were high, ranging from 0.73 to 0.94 across individual samples, and from 0.84 to 0.91 for the combined sample.

The results are consistent with the conceptual notion that schizotypal personality is a multifaceted construct and support the validity and utility of SPQ in cross-cultural research. We discuss theoretical and clinical implications of our results for diagnostic systems, psychosis models and cross-national mental health strategies.

Visual hallucinations (VH) are common symptoms in schizophrenia and other psychoses. An understanding of their cross-sectional and longitudinal patterns of association with auditory hallucinations (AH) is essential for developing accurate models of hallucinatory phenomena.

This study presents the most comprehensive examination of the association between VH and AH, and its change over time, in 1303 individuals with first-episode psychosis (FEP) and 469 individuals with chronic schizophrenia.

The samples included data from the WHO multicentre study on the Determinants of Outcome of Severe Mental Disorders and the Western Australian Family Study of Schizophrenia (WAFSS). Standardized assessment of symptoms and functioning were used to examine the clinical profile and symptom co-occurrence of hallucinations over time.

VH were approximately half as frequent as AH, almost always co-occurred with AH, and tended to be linked to a more severe psychopathological profile. AH and VH at baseline also predicted higher disability, risk of relapse and duration of psychosis after 1 and 2 years, especially when occurring in combination.

The findings point to three hallucination ‘subtypes’ with different symptom profile. The VH + AH combination signals greater psychopathology and a less favourable prognosis, than hallucinations occurring in isolation, and no hallucinations. This conclusion points to one common mechanism for all hallucinations, which can separate into distinct pathways and modalities. For a more complete clinical picture, clinicians should carefully probe for both auditory and VHs in presenting patients.

Numerous studies have reported neuropsychological impairment in schizophrenia and increasing evidence suggests that individuals with schizophrenia or schizophrenia spectrum disorders and their unaffected first-degree family members exhibit similar deficits in some neuropsychological domains. Substantial modifications to the Wechsler Memory Scale (WMS) have resulted in more sensitive and reliable indicators of various aspects of memory functioning in the WMS-III, which enables generation of auditory, visual and working memory indices.

The aim of the present study was to examine the memory profile of individuals with schizophrenia or schizophrenia spectrum disorder (n = 19), their unaffected first-degree family members (n = 11), and healthy controls (n = 9).

The study involved neuropsychological testing, including the immediate and working memory subtests of the WMS-III, utilizing both auditory and visual domains. Symptom assessment was performed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN), version 2.0. Two multivariate analyses of covariance (mancova) were conducted: (i) comparing patients, relatives and controls; and (ii) comparing relatives and controls only.

The first analysis indicated that the patient group obtained significantly lower index scores than both relatives and controls on all three indices. The second analysis indicated that the performance of relatives was significantly lower than controls on the working memory index, although there were no significant differences on the auditory and visual immediate index scores.

The differential impairment in working memory performance in clinically asymptomatic family members suggests that the WMS-III working memory index score may be a potential phenotypic marker of schizophrenia.