There is provided a system (100) for assessing delirium in a subject. The system includes a neural activity assessment module (102) for assessing neural activity data associated with the subject. The system also includes a delirium cause assessment module (104) for assessing data relating to at least one factor of a plurality of factors which contribute to the cause of delirium. The system also includes an intervention determination module (106) for determining, based on the assessment performed by the delirium cause assessment module, at least one intervention for reducing the contribution made by the at least one factor. A computer-implemented method and an apparatus are also disclosed.