Understanding and treating psychotic-spectrum disorders presents a great challenge for psychiatry; such psychopathology is complex and involves disruptions that span basic neural mechanisms and higher order cognitive processes. That these disruptions can occur in many variations, over the course of development, and unfold with epigenetic variants interacting with environmental events, helps to define the scope of the substantial heterogeneity characteristic of psychosis syndromes.  Here, we argue that the Research Domain Criteria (RDoC) offers an approach to facilitate progress by providing a framework to catalog and relate dimensional disruptions in neural systems, psychological processes, and behaviors relevant to understanding psychotic-spectrum psychopathology. We further argue that the “grain-size” of the psychotic clinical syndromes is too large to deconstruct the heterogeneity of psychotic disorders as they are currently defined and reiterate defining principles of RDoC that offer an alternative for researching psychosis.