Expanding the domain of the understandable in psychiatric illness: an updating of the Jasperian framework of explanation and understanding

Jaspers famously argued that psychiatry has two distinct ways of knowing about psychiatric illness: explanation - which utilizes natural sciences, and objective and empirical methods; and understanding - which reflects our subjective, empathic appreciation of our patients' experiences. He saw a clear division between these two approaches and considered a number of psychotic symptoms to be fundamentally un-understandable. We here argue for an updating of Jasper's view that includes the possibility, due to advances in neuroscience and neuropsychology, for explanation-aided understanding. We describe two scientific explanatory models for kinds of psychotic symptoms deemed un-understandable by Jaspers that illustrate this process. The first describes how dysfunction of the brain dopamine salience system may produce ideas of reference. The second demonstrates that symptoms of made-actions may be caused by abnormalities in the feed-forward motor control system. Both of these models begin at a biological level describing pathological brain processes in neuroscience language but then utilize neuropsychology to 'translate' from brain dysfunction into the mental. Both models break down the pathological pathways into individual subjective elements (particularly misattributing meaning to environmental stimuli and having body parts moved by others) that are understandable because they are common to nearly all of us. The neuropsychology provides hypotheses about the functional and physiological structures underlying familiar subjective experiences. Analyses of disorders of those structures thus provide a scaffold for expanding our empathic understanding of the subjective experiences of those suffering from psychiatric illness.