Understanding Lifespan Trajectories of Social Cognition, Brain Microstructure and Iron Dysregulation in Schizophrenia

This study aims to better understand how schizophrenia may affect social thinking, emotion regulation, brain function, and biological processes over time. Two groups will take part in the study: 1. people diagnosed with schizophrenia 2. healthy adults without schizophrenia Participants in both groups will complete a series of behavioral tasks and questionnaires. These will assess abilities such as understanding other people, processing social information, and regulating emotions. For participants with schizophrenia, we will also assess clinical symptoms and their severity. The study includes three assessment visits: 1. Baseline: at the beginning of the study 2. 12-month follow-up: approximately one year later 3. 24-month follow-up: approximately two years later At all three visits, participants will complete behavioral tests and questionnaires, and blood and hair samples will be collected. These samples may help researchers investigate biological factors that are related to mental health, stress, and changes over time. Participants will also undergo an MRI brain scan at the baseline visit and again at the 12-month follow-up. People with schizophrenia may experience changes in thinking, emotions, social functioning, physical health, and brain function across adulthood. However, we still do not fully understand how these changes develop over time or how they differ from normal aging. By comparing people with schizophrenia with healthy adults of different ages and following them over time, we can study possible differences in aging trajectories. This means examining whether certain abilities, symptoms, biological markers, or brain characteristics change differently with age in people with schizophrenia. The study uses an accelerated longitudinal design. Instead of following one group of people for many decades, researchers recruit participants from different age groups and follow them for a shorter period. Combining information across these age groups can help researchers estimate longer-term patterns of change.

Inclusion criteria (all participants): age 18-70 years at baseline; normal or corrected-to-normal vision; sufficient hearing; fluency in German; willingness and ability to understand and comply with study procedures. Participants must either be healthy adults without any mental health disorder (HC) or have a confirmed DSM-5 diagnosis of SZ. Inclusion criteria (SZ only): clinical stability at assessment, defined as no clinically significant change in psychopathological symptoms and no modification of pharmacotherapy for at least three months prior to study entry, as confirmed by the treating psychiatrist; full remission is not required. Exclusion criteria (all participants): incapacity to consent; current or lifetime history of brain surgery or epilepsy; MRI contraindications (unremovable metal parts in the upper body, active implants, claustrophobia); current or past substance abuse disorder (excluding caffeine and nicotine); pregnancy. Exclusion criteria (HC only): any current or lifetime Axis I psychiatric disorder; first-degree relative with an Axis I disorder; any neurological disorder or other mental health condition; current or past use of psychotropic medication. Additional Eligibility Criteria for Cycle-Timed Neuroimaging: To minimize hormonal confounding of emotion-regulation-related neural measures, menstruating female participants will be scanned in the early follicular phase (cycle days 1-6), requiring regular menstrual cycles (21-35 days) and a negative pregnancy test at relevant visits. Use of hormonal contraception will be recorded.