Adhesio interthalamica in individuals at high-risk for developing psychosis and patients with psychotic disorders.

Abnormal neurodevelopment in midline structures such as the adhesio interthalamica (AI) has been reported in psychotic disorders, but it is unknown whether individuals at risk for the disorder share the AI findings observed in patients with florid psychosis. Magnetic resonance imaging of 162 patients with first-episode psychosis (FEP), 89 patients with chronic schizophrenia, 135 individuals at ultra high-risk (UHR) of psychosis (of whom 39 later developed psychosis), and 87 healthy controls were used to investigate the length and prevalence of the AI. The relation of the AI length to lateral ventricular enlargement was also explored. The patients with FEP and chronic schizophrenia as well as UHR individuals had a shorter AI than the controls, but there was no difference in the AI findings between the UHR individuals who did and did not subsequently develop psychosis. There was a negative correlation between the AI length and lateral ventricular volume in all the diagnostic groups. The absence of the AI was more common in the chronic schizophrenia patients when compared with all other groups. These results support the notion that the AI absence or shorter length could be a neurodevelopmental marker related to vulnerability to psychopathology, but also suggest that schizophrenia patients may manifest progressive brain changes related to ongoing atrophy of the AI after the onset.