There are a standard set of diagnostic methods and scientific methods used for mental illness, both in the United States and all over the world. This site describes this set of diagnostic and scientific methods for mental disorders. It is the sixth revision of the site.
Diagnostic Methods
Psychiatrists, psychologists, and other mental health professionals seek to provide a mental disorder diagnosis through an assessment of symptoms, signs and impairment associated with a particular mental disorder. Many mental health issues are often diagnoses initially by family physicians during consultations, who may refer a patient on for more specialist diagnosis in acute or chronic cases.
Routine diagnostic practice in mental health services typically involves an interview known as a mental status examination during an intake interview, where evaluations are made of appearance and behavior, self-reported symptoms, mental health history, and current life circumstances. The views of other professionals, relatives or other third parties may be taken into account. If seen initially by a physician or psychiatrist, a physical examination to check for ill health or the effects of medications or other drugs may be conducted. Psychological testing is sometimes used via paper-and-pen or computerized questionnaires, which may include algorithms based on standardized diagnostic criteria. In rare cases, neuroimaging tests may be requested, but such methods are more commonly found in research studies than routine clinical practice.
Time and budgetary constraints often limit practicing psychiatrists from conducting more thorough diagnostic evaluations. It has been found that most clinicians evaluate patients using an unstructured, open-ended approach, with limited training in evidence-based assessment methods, and that inaccurate diagnosis may be common in routine practice. In addition, comorbidity is very common in psychiatric diagnosis, where the same person meets the criteria for more than one disorder. On the other hand, a person may have several different difficulties only some of which meet the criteria for being diagnosed. There may be specific problems with accurate diagnosis in developing countries.
There is not always agreement amongst different mental health professionals about the diagnosis of a mental disorder for any given individual. While all professionals use the same diagnostic manual (the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition also known as the DSM-5), symptoms may not be observed in a similar manner in the same patient. This has long been a criticism of the lack of validity of mental disorder diagnoses.
Mental disorders have a varied course once diagnosed, depending on the type of mental disorder, its severity, the person it impacts, and the resources available to treat it. Some mental disorders can resolve within a few months, while others may be with a person for years. For some diagnoses, like bipolar disorder and schizophrenia, a mental disorder may be something a person lives with their entire lives, much like some people live with diabetes or skin conditions.
Scientific Methods
The scientific method is the process by which science is carried out. As in other areas of inquiry, science (through the scientific method) can build on previous knowledge and develop a more sophisticated understanding of its topics of study over time.
The scientific method can be thought of as simply a structured process of trial-and-error. And to ensure there's no professional cheating in the process, science is generally reviewed (and in some ways, vetted) by other scientists (called 'peer-review').
The overall process involves making conjectures (hypotheses), deriving predictions from them as logical consequences, and then carrying out experiments based on those predictions to determine whether the original conjecture was correct. There are difficulties in a formulaic statement of method, however. Though the scientific method is often presented as a fixed sequence of steps, these actions are better considered as general principles.
In researching of mental illness, science looks for answers in a wide variety of fields. These fields include psychology, neurology, neuroscience, medicine, psychiatry, sociology, and social psychology, among others. Each field has its own set of scientific professional journals in which research results are disseminated. This process of publication is called "peer-review," because other researchers review the experimental study before it is approved for publication. This is an effort to only allow the publication of higher-quality scientific studies, but often fails to act as a gate-keeping device.
This page was written by David Harrison, Ph.D. and may be based on materials from other sources. Last updated: 14 Apr 2024