A problem is defined when the clinician judges a dysfunction is apparent or highly probable for the patient in one or more of three areas: physiological, psychological, or social functioning. In defining specific problems, data assessments are often confounded with the data themselves. To "lump" or "split" problems in psychiatry should be by theoretical and practical considerations. Problem indicators should be "split" when the clinician believes they are not different indicators of the same problem or treatments for the problem indicators will be different. They can be "lumped" when the clinician believes they are different indicators of the same problem, or when the treatment will be the same. Criteria supporting the belief of a single problem construct are met when indicators co-vary, are functionally equivalent, or respond similarly to the same treatment variable.
Fowler DR, Longabaugh R. The Problem-Oriented RecordProblem Definition. Arch Gen Psychiatry. 1975;32(7):831-834. doi:10.1001/archpsyc.1975.01760250023001