The present invention relates to assessing a psychophysiological responsiveness or non-responsiveness of a subject. A device (10) for assessing a psychophysiological responsiveness of a subject is presented, the device comprising a stimulus unit (11) for providing an electrical stimulus via a first and a second electrode (21, 22) to a skin (100) of the subject； a sensing unit (12) for acquiring an impedance signal (15) indicative of an impedance between the first and the second electrode in response to said electrical stimulus； and an analysis unit (13) adapted to identify an electrical double-layer based on the impedance signal acquired in response to the electrical stimulus and to determine a psychophysiological responsiveness of the subject based on the identified electrical double-layer. It has been found that identifying the presence or absence of an electrical double-layer based on the impedance signal acquired in response to the electrical stimulus can serve as a reliable indicator whether the subject is in a responsive or nonresponsive psychophysiological state. Further, a corresponding method, computer program and system (1) are presented.
