Interaction of negative olfactory stimulation and working memory in schizophrenia patients: development and evaluation of a behavioral neuroimaging task.

Negative affect plays a crucial role in the psychopathology of schizophrenia. Although it is known that negative emotion has a strong effect on cognitive performance, this interaction has mainly been studied in healthy volunteers. Hence, working memory was assessed in 24 schizophrenia patients and 24 matched comparison subjects with a 0-back/2-back continuous performance test. Simultaneously, negative emotion was induced by olfactory stimulation. Although subjective ratings confirmed that stimulation with a negative odor was associated with a significant increase in negative affect in patients and healthy volunteers, working memory performance was affected differentially in healthy volunteers and schizophrenia patients. Whilst a similar trend of a reduced behavioral performance during negative odor stimulation was observed in patients, only controls demonstrated a significantly higher response time and a reduced number of correct reactions during higher working memory demands (2-back). Patients, on the other hand, revealed an increase in false alarms during both conditions. The present data indicate a differential effect of negative mood induction on working memory performance in schizophrenia patients and healthy subjects.