I’m part of the team writing the next bible of psychiatry – for the first time, the DSM will use biology to understand mental disorders

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is widely used by clinicians to diagnose mental health conditions and by researchers to guide studies. Published by the American Psychiatric Association, it serves as a standard reference for mental health professionals globally. The most recent edition, DSM-5, released in 2013, has faced criticism for lacking objective biological measures in its diagnostic criteria. Critics argue that this absence risks treating normal human emotions as mental illnesses and weakens the validity of psychiatric diagnoses. The DSM is often referred to as the 'bible' of psychiatry due to its authoritative role in shaping how mental disorders are understood and treated.

The next edition of the DSM, expected in the coming years, will introduce biological factors for the first time in its history. This shift aims to modernize psychiatric diagnosis by incorporating neurobiology—the study of the nervous system’s role in mental health. A strategic committee, including the author, worked between May 2024 and August 2026 to integrate neurobiological findings into the manual. Researchers acknowledge that the biological basis of mental disorders is still not fully understood, so they are adopting a cautious approach to include measurable biological markers (biomarkers) where possible, rather than overhauling the entire diagnostic system.

Biomarkers are measurable indicators of biological processes that can help diagnose diseases, monitor their progression, or predict responses to treatment. For example, hemoglobin A1C levels are used to diagnose and manage diabetes, while cholesterol levels assess cardiovascular risk. Biomarkers are collected through methods like blood tests, imaging scans, or genetic analysis. In psychiatry, however, no scientifically valid biomarkers currently exist for any mental disorder, except for certain proteins used in diagnosing Alzheimer’s disease. The lack of biomarkers in psychiatry is primarily due to the subtle and complex nature of brain-related disorders, which are influenced by both biological and environmental factors such as genetics, trauma, and family history.

Mental disorders are not discrete illnesses but rather behavioral syndromes—clusters of overlapping symptoms and signs. For instance, anxiety and mood disorders often share symptoms, and conditions like schizophrenia and bipolar disorder with psychosis frequently co-occur. This overlap complicates diagnosis because it suggests that these disorders may share genetic or environmental risk factors. Unlike diseases such as tuberculosis or diabetes, which were later linked to specific biological causes, mental disorders remain syndromes without clear, single biological pathways. This complexity makes it difficult to identify a single biomarker that could reliably diagnose multiple conditions.

While research is ongoing, three neurobiological advances show promise for improving psychiatric diagnosis. First, biomarkers for Alzheimer’s disease have been developed, including a blood test approved by the U.S. Food and Drug Administration in March 2025. This test detects abnormal proteins (amyloid and tau) associated with the disease, marking the first biomarker for a brain-related behavioral disorder. Second, immune factors such as C-reactive protein (CRP) have been linked to depression; approximately 30% of patients with depression have high CRP levels, suggesting a potential subtype that may respond better to specific treatments. Third, genetic risk factors—genes that increase the likelihood of developing a mental disorder—are being studied. Researchers are developing polygenic risk scores to estimate disease risk by combining multiple genetic variants.