Recent empirical findings of mental disorders have put forward the concept of spectrum, which suggests that mental disorders could be conceptualized as dynamic continua ranging from health to subclinical traits to disorders. Studying sub-clinical populations could help the understanding of early neurophysiological abnormalities prior to the onset of clinical disorder. It also facilitates the understanding of the developmental pathway of mental disorders and the protective or risk factors involved in this process, which could inform early detection and intervention of psychiatric disorders.

Dr. Raymond Chan, together with his team from the Institute of Psychology, has recently shown that co-morbidity of schizophrenia and obsessive-compulsive disorder (OCD) exhibited severe brain resting-state functional connectivity, comparing with individuals with either schizophrenia or obsessive-compulsive disorder alone. However, it is still not clear whether a similar pattern of altered functional brain connectivity would have been exhibited in individuals with co-occurrence of the schizotypal traits and obsessive-compulsive symptoms.

Dr. Chan's team has examined the Default Mode Network (DMN) and whole brain voxels in 30 individuals with high schizotypal traits (SCT), 20 with high obsessive-compulsive traits (OCT), 22 individuals with high schizo-obsessive traits (SOT), and 30 with low traits scores (LT).

"While individuals with SOT, SCT and OCT exhibited different degrees of altered functional connectivity, individuals with SOT exhibited the most reduced functional connectivity within the DMN compared with the other groups," said Dr. Chan, "the SOT group also exhibited increased connectivity between the DMN and the Salience Network, and between the DMN and the Auditory Network with the LT group."

These findings not only echo previous clinical samples with co-morbidity of schizophrenia and OCD, but extend to subclinical samples with co-occurrence of schizotypal and OCD traits.

"They may be helpful to understand the pathophysiology of schizophrenia and OCD, and guide us to develop precision brain science approach for clinical diagnosis and management of schizophrenia and OCD in the near future," added Chan.

This study was supported by grants from the National Key Research and Development Programme, the Beijing Municipal Science & Technology Commission Grant, the Beijing Training Project for the Leading Talents in Science and Technology, the Strategic Priority Research Programme (B) of the Chinese Academy of Science, and the CAS Key Laboratory of Mental Health, Institute of Psychology.