Thalamic volume deficits are associated with psychosis but it is unclear whether the volume reduction is uniformly distributed or whether it is more severe in particular thalamic regions.

To quantify whole and regional thalamic volume in males with early-onset psychosis and healthy male controls.

Brain scans were obtained for 80 adolescents: 46 individuals with early-onset psychosis with a duration of positive symptoms less than 6 months and 34 healthy controls. All participants were younger than 19 years. Total thalamic volumes were assessed using FreeSurfer and FSL-FIRST, group comparisons of regional thalamic volumes were studied with a surface-based approach.

Total thalamic volume was smaller in participants with early-onset psychosis relative to controls. Regional thalamic volume reduction was most significant in the right anterior mediodorsal area and pulvinar.

In males with minimally treated early-onset psychosis, thalamic volume deficits may be most pronounced in the anterior mediodorsal and posterior pulvinar regions, adding strength to findings from post-mortem studies in adults with psychosis.

Adolescents with first-episode psychosis have increased severity of neurological soft signs when compared with controls, but it is unclear whether increased severity of neurological soft signs is an expression of specific structural brain deficits.

To examine whether increased severity of neurological soft signs was associated with decreased brain volumes in adolescents with first-episode psychosis.

Brain scans were obtained for 70 adolescents (less than 18 years of age) with first-episode psychosis (duration of positive symptoms less than 6 months). Volumes were assessed using voxel-based morphometry and through segmentation of anatomical structures.

Increased severity of sensory integration neurological soft signs correlated with smaller right and left thalamus volume, whereas increased severity of sequencing of complex motor acts neurological soft signs correlated with smaller right caudate volume.

Neurological soft signs may be an easy-to-assess marker of region-specific structural brain deficits in adolescents with first-episode psychosis.