The goal of this clinical trial is to investigate for the first time in people with schizophrenia a neural mechanism that is thought to facilitate the formation of social connections - inter-brain synchrony - in order to improve scientific understanding of the neural mechanisms of social dysfunction in the disorder, and to provide a basis for the development of new and better treatments to improve social functioning and connectedness in the illness. The main questions it aims to answer are:

1. Investigate inter-brain synchrony as a neural mechanism of social connection in schizophrenia
2. Manipulate social closeness and test for effects on inter-brain synchrony across groups

The investigators will compare results from people with schizophrenia to a healthy comparison group (controls) who do not have psychotic disorders to see if inter-brain synchrony is greater in controls. Investigators will also compare measures of inter-brain synchrony before and after the social closeness manipulation to see if inter-brain synchrony changes with increasing closeness.

Participants will:

• Have a clinicial diagnostic interview and be assessed for clinical symptoms
• Have an EEG recorded while interacting with another person. Participants will first work with the other person to draw a figure, and then tap fingers together. Participants will then either undergo the experimental manipulation to increase social closeness (called, "fast friends") or undergo the control condition that does not increase social closeness (called "small talk"). Participants will then repeat the drawing and finger tapping assessment.
• After completing the experimental or control condition, participants will then repeat the procedure with the other condition that was not yet done.
• Be interviewed on the number and quality of social interactions.

Inclusion Criteria:

• sufficient English fluency to comprehend procedures
• clinical group will include individuals with a DSM-5 diagnosis of schizophrenia who are clinically stable (outpatients, with no hospitalizations 3 months prior to enrollment and no medication changes 1 month prior to enrollment)
• members of the community without a psychotic disorder, schizophrenia-spectrum disorder, or current major mood disorder, nor history of a first-degree relative with a psychotic disorder.

Exclusion Criteria:

• evidence of IQ < 70 or developmental disability
• history of significant neurological disease, serious head injury, or significant current substance use (moderate or severe substance use disorder in the last 3 months, positive urine toxicology screen on the day of assessment, or sedatives/anxiolytics taken within 12 hours of the assessment)

EEG measures of interbrain synchrony, clinicial symptom ratings, social connectedness measures

At the end of the study (November 2027) for indefinite period

These data will be shared on the NIMH Data Archive