Studies of people with schizophrenia assessed using magnetic resonance imaging (MRI) usually include patients with first-episode and chronic disease, yet brain abnormalities may be limited to those with chronic schizophrenia.

To determine whether patients with a first episode of schizophrenia have characteristic brain abnormalities.

Systematic review and meta-analysis of 66 papers comparing brain volume in patients with a first psychotic episode with volume in healthy controls.

Atotal of 52 cross-sectional studies included 1424 patients with a first psychotic episode; 16 longitudinal studies included 465 such patients. Meta-analysis suggests that whole brain and hippocampal volume are reduced (both P < 0.0001) and that ventricular volume is increased (P < 0.0001) in these patients relative to healthy controls.

Average volumetric changes are close to the limit of detection by MRI methods. It remains to be determined whether schizophrenia is a neurodegenerative process that begins at about the time of symptom onset, or whether it is better characterised as a neurodevelopmental process that produces abnormal brain volumes at an early age.

Scarce longitudinal data exist on the occurrence of psychotic symptoms in the general population.

To estimate the incidence of, and risk factors for, self-reported psychotic symptoms in Great Britain.

Data from the 18-month follow-up of a national survey were used. Incident cases were those who endorsed one or more items on the Psychosis Screening Questionnaire at follow-up, but not at baseline. The association between factors recorded at baseline and incident self-reported symptoms was examined.

At follow-up, 4.4% of the general population reported incident psychotic symptoms. Six factors were independently associated with incident symptoms: living in a rural area; having a small primary support group; more adverse life events; smoking tobacco; neurotic symptoms; and engaging in a harmful pattern of drinking.

A small but not insignificant percentage of the population of Great Britain reported incident psychotic symptoms over 18 months. The risk factors for psychotic symptoms showed some similarities with risk factors for schizophrenia, but there were also some striking differences. The relationship between such risk factors and the factors that perpetuate psychotic symptoms remains to be ascertained.