The term may also be used pejoratively to describe disputed medical conditions. In this sense, the term is somewhat pejorative, in that it implies that the condition has not been properly classified. It can carry a connotation that the prognosis of individuals with the condition are more heterogeneous than would be associated with a more precisely defined clinical entry. As diagnostic tools improve, it is possible for these kinds of wastebasket diagnoses to be properly defined and reclassified as a clinical diagnosis.
In the best circumstances, a trashcan diagnosis gives the patient and physician a convenient label for talking about the patient's problems while they are attempting to address the specific issues. In the worst circumstances, the existence of the label results in the patient and physician "treating the label" instead of treating the patient's actual problems.
Diagnoses which include a wide variety of complaints and symptoms are particularly prone to being used as trashcan diagnoses, as well as diseases with variable presentations. For example, fibromyalgia has been used as a trashcan diagnosis to describe chronic pain. Costochondritis, gastroesophageal reflux, and chronic fatigue syndrome are all commonly used as trashcan diagnoses. Bronchitis may be used as a trashcan diagnosis to label sick children. Reactive hypoglycemia has been used as a trashcan diagnosis for people who complain about normal physiological reactions to being hungry. In these cases, the labels are offered when nothing more serious can be identified.
Some diagnoses are being used as trashcan diagnoses in response to unintentional incentives. For example, government-run schools in the United States get additional funding for providing services to students with autism spectrum disorders, so some children with nontypical behavior patterns are labeled as having ASD so that the school can obtain more funding.
Some trashcan diagnoses such as schizophrenia have become more narrowly defined and are now used to refer to specific problems. Others, such as borderline personality disorder, have had a variety of definitions over the years.