Psychiatric diagnoses and formulations have classically focused on the chief complaint of the patient as part of a larger pattern of episodes and reactions. This is a form of state analysis in which the problem states of a person are carefully described and distinguished from other states. The authors suggest methods for deepening such formulations by grounding description of problem states in models of other states and models of state transitions. The resultant method of state analysis can be applied to examination of change processes during treatment as well as to initial diagnostic formulations. As an example of its use and possible extension to quantification, state analysis is applied to description of status and change in a person treated by brief psychotherapy. Because state analysis is based on observable behavior and reportable conscious experiences, it serves as a useful beginning point upon which to anchor more extended inferences about psychodynamics.