Neural Correlates of Social Touch and Interoceptive Perception As Potential Biomarker for Impaired Social Functioning

Alterations in psychosocial functioning are evident from the prodromal phase of schizophrenia and play a crucial role in its chronic course. While recent studies have demonstrated the predictive validity of structural changes in the brain anatomy of patients with schizophrenia, there is a lack of studies assessing the predictive value of disease-associated alterations in the functional brain activity for symptom severity and psychosocial functioning in schizophrenia.

In this longitudinal, observational study, 60 patients with schizophrenia and 40 healthy subjects without family history of psychotic illness will be recruited to investigate differences in behavioural, physiological, and neural correlates of social touch and interoceptive perception between participant groups. Participants' symptom severity and psychosocial functioning level will be examined by a wide range of behavioural, physiological, and neural methods. Potential biomarkers will be identified by estimating the predictive value of initially performed methods on follow-up re-examination of clinical and psychosocial outcomes. Neural readouts include structural and functional magnetic resonance imaging (fMRI) measurements. The fMRI tasks will probe the processing of social touch and interoceptive perception; additionally resting-state connectivity will be assessed. To further investigate pathological distortions of social touch and interoceptive perception, bodily touch allowance maps will be measured and participants will perform a heart-beat discrimination task. Psychometric questionnaires and semi-structured interviews will be used to capture symptom load and level of psychosocial functioning. Long-term effects will be assessed by online questionnaires and semi-structured interviews via phone call 3- and 6 months after initial assessments. The investigators hypothesize that differences in the neural response to social touch as well as in the neural patterns of interoceptive perception could serve as potential biomarkers for psychosocial deficits during the course of the illness. Furthermore, the inclusion of those biomarkers in predictive models could improve the prediction of disease progression and thus, contribute to personalized therapy.

Inclusion criteria

• Participant is able to provide consent.
• Diagnosis of schizophrenia or schizoaffective disorder according to DSM-V
• Control group: No psychiatric or neurological illness.
• Fluent in German.

Exclusion criteria

• The participant does not fulfill requirements for MRI measurements according to safety guidelines.
• Acute suicidality.
• Current substance dependence.
• A history of head trauma or neurological illness.