In a new study published in Schizophrenia Bulletin on Dec. 23, researchers led by Dr. Raymond Chan from the Institute of Psychology of the Chinese Academy of Sciences have examined patients with co-morbidity of schizophrenia (SCZ) and obsessive-compulsive disorder (OCD), a condition known as "schizo-obsession" (SOC), and showed that there were specific superimposed neural effects of combined schizophrenia and obsessive-compulsive symptoms at both white matter connectivity and resting-state functional connectivity, compared to patients with either schizophrenia or obsessive-compulsive disorders, as well as healthy controls.

The researchers also found a similar but attenuated pattern of altered connectivity in individuals with both traits.

Traditionally SCZ and OCD have been considered as two distinct mental disorders. Recent evidence suggests that these two clinical groups may share a lot of similarities, including behavioral manifestations and cognitive impairments, including executive functions. However, previous research did not use a task-based functional MRI (fMRI) paradigm to directly investigate the neural mechanisms underlying cognitive impairments in patients with SOC.

To address this knowledge gap, CHU Minyi and Prof. YI Zhenghui from the Shanghai Mental Health Centre and Dr. Chan recruited 28 patients with SOC, 33 SCZ patients with SCZ, 30 patients with OCD, and 33 healthy controls to complete a task capturing shifting go/no-go performance inside the brain scanner.

The researchers found that patients with SCZ, OCD and SOC exhibited significantly lower shifting-related brain activation at the left postcentral gyrus, left paracentral lobule, left supplementary motor area, and right superior frontal gyrus. Patients with SOC also exhibited significantly lower brain activation than patients with SCZ and OCD.

Furthermore, patients with OCD exhibited significantly greater brain activation in the left precuneus than patients with SCZ and healthy control subjects while performing the stopping task. Both OCD and SOC patients exhibited greater brain activation than SCZ patients.

These findings together support a transdiagnostic framework of schizophrenia and OCD. Reduced brain activation related to shifting may be a biosignature shared by patients with SCZ, OCD, and SOC. Dr. Chan and his colleagues hope these findings will guide the development of a precision brain science approach to diagnosing and intervening in psychosis spectrum disorders and OCD.