Brain fMRI finds people with schizophrenia less reactive to positive social experiences

UCLA researchers have found that the brains of people with schizophrenia are less reactive to social rewards such as positive interactions with others and smiling, according to research published Sept. 5 in Schizophrenia Bulletin.  

The findings demonstrate how people with schizophrenia are more likely to find social stimulation unrewarding and contribute to problems with socializing, wrote lead author Michael Green, PhD, a professor in residence of psychiatry and biobehavioral sciences at UCLA’s David Geffen School of Medicine, and colleagues.  

For the study, the researchers recruited 27 participants with clinically stable schizophrenia and 25 healthy controls to analyze the brain’s response to performing a given task in a fMRI scanner.  

The task involved participants to play a computerized version of a slot machine, according to the researchers. The game had two categories of payout: images of dollar bills or of happy human faces. Participants were then asked which machines ha the best payout in each category.  

When comparing machines that gave dollar-bill payouts, levels of brain activity were similar in people with and without schizophrenia. However, when comparing machines that gave payouts of human smiling faces, brain activity was found to be much lower in those with schizophrenia than compared to the healthy controls. 

“This study found reduced neural sensitivity in patients with schizophrenia in key reward-processing regions for social but not for nonsocial rewards,” Green et al. wrote. “These findings suggest a relatively specific social reward-processing deficit in schizophrenia during an implicit reinforcement learning task.”  

The study was funded by The National Institute of Mental Health and the Brain & Behavior Research Foundation.