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Mental health diagnoses and DSM-5 in the legal system
The ubiquitous guide leaves many psycho-legal questions unanswered

Dr. Michael MacIntyre
December 2021

Most mental health providers rely on the Diagnostical Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), a system of classification of mental illnesses. The DSM-5 was created primarily to help mental health professionals treat patients, allowing them to use a common language, communicate clearly, and remain consistent with diagnoses in treatment and research settings.[1]

Questions of mental illness are often germane to legal matters. However, the DSM-5 was not designed with legal interests in mind. In fact, the DSM-5 includes an explicit cautionary statement about using it in forensic settings. This warning notes the imperfect fit between the ultimate questions of concern to the law and criteria that make up a diagnosis:

[It] is important to note that the definition of mental disorder included in DSM-5 was developed to meet the needs of clinicians, public health professionals, and research investigators rather than all of the technical needs of the courts and legal professionals. It is also important to note that DSM-5 does not provide treatment guidelines for any given disorder.

Some legal questions do explicitly require the presence of a mental illness—for instance, there may be a statutory requirement of mental illness for involuntary civil commitment. However, in most cases the mere presence of a diagnosis has little to do with the ultimate legal question. For example, someone who meets all the DSM-5 diagnostic criteria for schizophrenia does not necessarily also meet the legal test for not guilty by reason of insanity. People with major neurocognitive disorder may still have testamentary capacity as long as they retain the capacities necessary to create a will. Conversely, someone who does not meet the DSM-5 criteria for post-traumatic stress disorder may still have significant mental impairments and emotional distress relevant in a tort claim.

A diagnosis alone does not provide any information about the severity of impairments or the abilities and disabilities a person may experience. In fact, there are a wide variety of presentations that may satisfy the same diagnosis. To illustrate, the DSM-5 uses nine criteria to define Major Depressive Disorder, but only five must be present to meet the criteria for diagnosis. Thus, there are 227 possible unique symptom combinations that all meet the criteria for this one diagnosis. Even though only a small subset of symptom combinations is seen in clinical practice, simply relying on this diagnosis in a courtroom may not provide sufficiently specific information about any one individual. However, a thorough clinical history and evaluation provides context to any diagnosis. An individual’s history, personal experience, culture, and gender are some of the many factors that may affect how mental illness presents.

Limitations and cautions

There are other limitations with the DSM-5. Some mental health problems are not adequately captured by the DSM-5. Even for the diagnoses it does include, the DSM-5 does not offer treatment recommendations or a prognosis for any individual. Furthermore, at any given moment, the DSM-5 may not reflect the most accurate or current state of knowledge about a given condition. It may not include recently formulated diagnoses or novel diagnoses currently being researched. The creators of the DSM-5 are aware that science isn’t static, and the DSM-5 specifically includes a section on areas for future study.

Changes in the science and practice of psychiatry are inevitable. This can be seen by through the substantial changes between the prior edition (DSM IV) and DSM-5. DSM-5 removed the prior edition’s “multi-axial” system for describing diagnoses entirely.[2] Even the naming of the newest DSM represented a significant change: the transition from the Roman numeral editions (I-IV) to the Arabic numeral with the 5th edition was meant to allow for revisions without a complete overhaul. Revisions can now be easily identified – for example, DSM-5.2 followed by DSM-5.3, and so on. With this system, new information can be added or edited without needing to create completely new manuals. Ideally, this will allow for the more rapid integration of new information.

Psychiatrists must use caution to avoid using DSM as a “cookbook” to prove or disprove a diagnosis by simply checking off a list of reported symptoms. Sometimes, experts may be tempted to provide the diagnosis that most closely represents a particular situation. This is clinically inappropriate and misleading, and it should be avoided.

Beyond the manual

For many symptom clusters, such as mood symptoms and psychotic symptoms, the DSM-5 allows for other specified or unspecified diagnoses. For example, if someone does not meet sufficient criteria for Major Depressive Disorder, Persistent Depressive Disorder, or Bipolar Disorder—but nevertheless has impairing depressive symptoms—they might be described as having an “other specified depressive disorder”. The use of “other specified” diagnoses allows the psychiatrist to explain why an evaluee does not meet the criteria for a diagnosis but still has clinical distress or impairment. The evaluee might meet some but not all of the symptomatic criteria or might not meet all the criteria long enough to meet the definition of a disorder.

The “unspecified” category, on the other hand, is meant for when a psychiatrist does not provide information as to why criteria are not met. It may include presentations for which there is insufficient information for a more specific diagnosis (such as in emergency settings). Forensic psychiatrists, provided they receive sufficient time, collateral, and chances to evaluate someone, should be able to specify why someone does not meet criteria for a diagnosis and use the “other specified” label, if appropriate, instead. Sometimes, a psychiatrist may “rule out” or “defer” a diagnosis—something I will write more about in a future post.


While the DSM-5 is incredibly important to classification and understanding of mental illness, it was not meant to solve all psycho-legal questions. Sometimes a diagnosis isn’t necessary at all—for example, mitigating evaluations and emotional distress evaluations may not result in a DSM-5 diagnosis but may still uncover findings relevant to a court. Almost always, a diagnosis is insufficient to answer any legal questions. Though the presence or absence of a DSM-5 diagnosis is often argued in court and it is very important to appropriately diagnosis, much more important is a scientific understanding of how one’s capacities, behaviors, and disabilities are affected.


  1. While the DSM-5 is the standard edition used in most jurisdictions and settings, some (such as workers’ compensation) may use an older edition. ↩︎

  2. It should be noted, however, that eliminating this system did not by itself change the characteristics of any diagnosis, but rather the manner in which such information was conveyed. ↩︎

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