BACKGROUND There is a tension within contemporary psychiatric nursing between those who would embrace the knowledge and methods of psychiatry and psychology, and those who instead argue for the development of an autonomous nursing profession. This tension cannot be resolved by way of the underpinning philosophies of these positions, namely empiricism and idealism. Instead, critical realism, positioned between these philosophies offers a methodology through which to seek a new paradigm. OBJECTIVE This paper aims to determine whether psychiatric nursing has the potential to exist as an independent and autonomous profession, concerned with providing a helping response to those in mental distress. METHODS The paper asks critical realism's transcendental question in order to identify the a priori requirements of an autonomous psychiatric nursing, independent of both psychiatry and psychology. Consideration of these a priori requirements includes selected information from contemporary texts in order to identify potentially helpful nursing responses to mental distress, as opposed to the theorising that surrounds these helping responses. RESULTS The theories of psychiatry and psychology are neither necessary nor sufficient in providing a foundation for an autonomous psychiatric nursing. While medications have an intrinsic helpfulness for some people, for some of their problems, for some of the time, this does not illuminate the causes of mental distress. There is an intrinsic helping response in human interpersonal communication, yet this is not specific to 'psychotherapy' and does not 'belong' solely to psychotherapists. CONCLUSIONS Support is found for an autonomous and independent profession of psychiatric nursing, able to provide a helping response to those in mental distress independent of psychiatry and psychology.