Magnetic resonance imaging of brain in people at high risk of developing schizophrenia

Background Schizophrenia is a multifactorial disorder that is associated wi th disturbed cerebral development, Structural brain-imaging studies have co nsistently shown that the volumes of some parts of the brain, particularly the mesial temporal lobes, are! smaller in patients with schizophrenia than in healthy people. Whether these abnormalities of brain structure predate the onset of symptoms is not known. Methods 100 people at high risk of developing schizophrenia (two or more fi rst-degree or second-degree relatives affected), 20 patients in their first episode of schizophrenia, and 30 healthy controls underwent magnetic reson ance imaging of the brain. The volumes of regions of interest were measured by standard techniques. Findings Mean whole-brain volume was 1356 cm(3) (SD 178) in the first-episo de group, 1347 cm(3) (122) in the high-risk group, and 1334 cm(3). (149) in the controls (p=0.8). The mean volume of the left amygdala-hippocampal com plex (AHC) was lower in the first-episode group (4.3 cm(3) [0.6]) than in t he high-risk group (4.6 cm(3) [0.6]), and in turn than in the controls (4.8 cm(3) [0.7]); these differences were significant (p<0.05) both for absolut e volumes and values adjusted for brain volume and other confounders. The r ight AHC showed a similar pattern (absolute volumes 4.5 cm(3) [0.7], 4.8 cm (3) [0.6], 4.9 cm(3) [0.9]; respectively). Both thalamic nuclei were signif icantly smaller in the high-risk group than in the control group. Interpretation People at high risk of developing schizophrenia for genetic reasons have several structural brain abnormalities that are similar to tho se in patients with the disorder. lit-risk individuals with particularly sm all AHC or thalami are most likely to develop schizophrenia, this feature m ight assist in early detection and treatment.