Background: A taxonomy of the objects of study, theory, assessment, and intervention is critical to the development of all clinical sciences. Clinical psychology has been conceptually and administratively dominated by the taxonomy of an adjacent discipline – psychiatry’s Diagnostic and statistical manual of mental disorders (DSM). Many have called for a ‘paradigm shift’ away from a medical nosology of diseases toward clinical psychology’s own taxonomy of clinical psychological problems (CPPs), without being able to specify what is to be listed and classified.

Main text: An examination of DSM’s problems for clinical psychology, especially its lack of clinical utility, and a search for the essence of CPPs in what clinical psychologists actually do, leads to the proposal that: The critical psychological-level phenomenon underlying CPPs is the occurrence of ‘problem-maintaining circles’ (PMCs) of causally related cognitions, emotions, behaviours, and/or stimuli. This concept provides an empirically-derived, theory-based, treatment-relevant, categorical, essentialist, parsimonious, and nonstigmatizing definition of CPPs. It distinguishes psychological problems in which PMCs have not (yet?) formed, and which may respond to ‘counseling’, clinical psychological problems in which active PMCs require clinical intervention, and psychopathological problems which are unlikely to be ‘cured’ by PMC-breaking alone.

Conclusion: A subsequent classification and coding system of PMCs is proposed, and expected benefits to research, communication, and the quality of case formulation in clinical psychology are described, reliant upon a development effort of some meaningful fraction of that which has been devoted to the DSM.