Where Is Our Understanding and Treatment of Mental Disorders Headed? — The Future of the DSM and Trauma

One of the diagnostic criteria widely shared among specialists dealing with mental illness is the DSM (Diagnostic and Statistical Manual of Mental Disorders). While the aim is to provide the same treatment for the same symptoms, there are concerns that it may not take into account the circumstances of individual patients

• Mental Illness Diagnosis and the DSM
• Call for international benchmarks
• A common language for drug and psychotherapy
• Limitations of validity of disease classification

Diagnosis of mental illness and the DSM

What is a mental illness? Unfortunately, modern psychiatry does not have a perfect answer. The pathology of mental illness has yet to be fully elucidated scientifically. This may raise concerns, asking, "So, how is mental illness treated?" Of course, modern psychiatry does have a system for diagnosis and treatment.

The global standard for diagnostic classification in modern psychiatry is the Diagnostic and Statistical Manual of Mental Disorders (DSM) published by the American Psychiatric Association. The current DSM, Fifth Edition (DSM-5), is also aware of this, stating in its introduction that the significance of diagnostic criteria lies in their clinical usefulness until the etiology is elucidated. In other words, diagnostic classification is meaningful if it can provide guidelines useful for treating patients at hand.

The DSM was first published in 1952 after the war and has undergone several revisions since then, with the third edition (DSM-III) published in 1980 being the most radical revision. This marked a major shift in the approach to diagnosing mental illness. The current fifth edition continues this basic philosophy.

Its approach is called "categorical diagnosis" or "operational definition." This means that if a patient's condition, particularly their psychiatric symptoms, meet the criteria for each disease category, they are considered to have a "certain disorder." The current DSM typically determines a disorder based on the presence or absence of symptoms over the past six months. This procedure allows for the diagnosis of a disorder by checking the presence or absence of each symptom according to an algorithm, leaving little room for subjectivity on the part of the diagnoser. In other words, anyone can make a diagnosis.

Call for international benchmarks

In fact, the DSM-3 edition rejected the psychoanalytic approach that had dominated American psychiatry up to that point. Because psychoanalytic treatment dominated American psychiatry, diagnosis emphasized each patient's unique history, including their upbringing. This was because psychoanalysis emphasized the patient's past trauma as the etiology of neurosis and other conditions. Therefore, therapists focused less on the symptoms themselves and more on the unconscious traumas and conflicts that lay behind them, often unnoticed by the patient.

Meanwhile, as biological psychiatry, based on drug therapy and biochemical research, advanced, there was a growing recognition that objective, internationally reliable indicators were needed to utilize these tools scientifically. However, a diagnosis that focused on individual histories did not ensure the validity of international comparisons of the same disorder.

Therefore, the DSM-3 edition made a major shift toward operational diagnosis based on the presence or absence of current symptoms required for each disorder category, regardless of the patient's past. This was an attempt to create a unified diagnostic classification from a comprehensive perspective. This promoted international standardization of diagnostic classifications of mental disorders, which had previously exhibited significant regional and cultural differences. The term "neurosis," which symbolizes psychoanalysis, disappeared from the DSM.

Currently, medical academic papers use the DSM criteria to describe individuals with mental illnesses, and the DSM's position as the global standard has been firmly established.

A common language for drug and psychotherapy

Furthermore, clinical psychology experts around the world share the DSM when assessing mental illness. This means that the DSM serves as a common language for a wide range of mental health professionals.

The American Psychological Association has compiled and published a list of psychological interventions for each DSM disorder, detailing the degree of scientifically supported treatment outcomes. This list shows that cognitive behavioral therapy is an effective intervention for many disorders.

This is a psychotherapy technique that combines cognitive therapy and behavioral therapy, but both methods offer some antithesis to psychoanalytic theory. As a result, for example, the most effective treatment for depression is one in which a diagnosis is made according to the DSM, a psychiatrist prescribes medication (antidepressants), and a psychologist provides cognitive behavioral therapy for depression.

Limitations of validity of disease classification

The second half of the 20th century saw significant advances in drug therapy and psychotherapy for mental illness, and the DSM's status as a global standard can be seen as a symbol of this success. However, despite the development of psychiatry and clinical psychology as social institutions, academic discussions have not necessarily progressed in elucidating the pathogenesis of mental illness itself. Recent

advances in genetic and neuroscience research have demonstrated the difficulty of explaining mental illness with a simple, reductive causal model, leading to the recognition that factors across multiple dimensions, such as individual genes, behavioral patterns, cognition, and social environment, interact in complex ways.

Therefore, the DSM-5 itself acknowledges that the current disease categories are not fully valid. While psychoanalytic theory as a causal theory of mental illness has been rejected, no comprehensive theory has emerged to replace it; in fact, some argue that no comprehensive theory exists at all.

Furthermore, while the DSM-3 edition supposedly excludes psychoanalytic theory, it includes the disorder PTSD (Post-Traumatic Stress Disorder), retaining the issue of trauma in mental illnesses that Freud, the founder of psychoanalysis, once raised. Moreover, nearly half a century has passed since the DSM-3 edition, and the history of intrafamilial trauma that Freud faced in his upbringing has become even more important in understanding patients today. It will be important to keep a close eye on future developments to see how the DSM will handle the resurfacing issue of trauma and how this will affect the understanding and treatment of mental illnesses.

(Article revised and expanded from the February 2025 issue of EN-ICHI FORUM)

References

• アメリカ心理学会（高橋三郎・大野裕監訳）『DSM-5 精神疾患の診断・統計マニュアル』（2014年）。

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