The link between physical fitness and the reward system in schizophrenia

• Applicant: Dr. Oliver Grimm
• Subject Area: Biological Psychiatry
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 445498183

Obesity, weight gain and reduced physical fitness are serious complications of mental illness, especially schizophrenia. They result from lifestyle and dietary changes, side effects of medication and other less well understood factors. However, our knowledge of the neuroscientific basis of weight gain and physical fitness in schizophrenia is currently limited. We hypothesise that changes in the reward system lead to obesity, body fat accumulation and increased cardiovascular risk. For the past 24 months, we have been studying patients with schizophrenia and healthy controls with regard to the reactivity of the reward system, clinical psychopathology as well as physical fitness. First evaluations show a dysregulated reactivity of the reward system as well as a reduced physical fitness associated with aspects of psychopathology (negative symptoms, anhedonia). In particular, we were able to demonstrate impaired connectivity of dopaminergic nuclear areas in patients with schizophrenia. This reduced connectivity in turn correlates with reduced fitness. In our follow-up application, two aspects should be mentioned that justify an extension of the study by 12 months. First, because of the Corona pandemic and the associated hygiene and lockdown measures, we were limited in the scope of our fMRI studies, even though recruitment was principally successful. This carries the risk that we will not be able to test core hypotheses of the initial application. Secondly, we want to supplement the concept of "physical fitness" with a measurement of basal metabolic rate and exercise by using an established measurement system with a GPS motion sensor. This will be complemented by an investigation of the microbiome, which interacts with behaviour and physical fitness.

• DFG Programme: Research Grants