The influence of interest in tasks on the autonomic nervous system.

Although prior studies have indicated the relationships among decreased parasympathetic activity, schizophrenia, and depression, the physiological effects of psychiatric occupational therapy tasks have not been adequately explored. Therefore, it is necessary to quantitatively examine the physiological changes in the autonomic nervous system when performing such tasks to devise more individualized therapies. Accordingly, we examined the influence of task interest and its relationship with psychological characteristics. The participants included in this study were 22 healthy individuals. They completed the State-Trait Anxiety Inventory, the Center for Epidemiologic Studies Depression Scale, and the Social Phobia Scale. Participants selected the most and least interesting bookmarks from a set of 19 different color options, and indicated their degree of interest on a visual analog scale. An electrocardiogram was used during each task to record participants' cardiac sympathetic index (CSI) and cardiac vagal index (CVI) as they performed two tasks (interesting and uninteresting). The correlations between the degree of interest and CSI/CVI, and between the scores of the questionnaires and CSI/CVI were examined. There was a negative correlation between the degree of interest and CSI during the uninteresting task. Task interest may have contributed to suppressing sympathetic dominance and reducing mental and physiological loads, even if the tasks differed only color-wise. Physiological effects emerged from participants' degree of task interest. Further identification of objective and therapeutic mechanisms may lead to wider applications of activities in different areas.