Subjective well-being can be predicted by caudate volume and promotion focus.

It is well-known that the caudate nucleus is associated with motivational behaviors and subjective well-being. However, no longitudinal studies have examined the relationship between brain structure, behavioral orientations, and subjective well-being. This study analyzes data from our previous longitudinal study to examine whether future subjective well-being can be predicted by the volume of the caudate nucleus. We also examined whether behavioral orientation, based on the regulatory focus theory showing two orientations-promotion and prevention focus-was related to the volume of the caudate nucleus. Voxel-based morphometry analysis indicated that the left caudate volume was positively associated with rating scores for future subjective well-being and promotion orientation. Further, mediation analysis indicated that promotion orientation significantly mediated the relationship between future subjective well-being and left caudate volume. The findings indicate that future subjective well-being can be predicted by the volume of the left caudate nucleus, and that this relationship is mediated by promotion focus orientation.