Psychiatrists treat mental health conditions like depression, anxiety, bipolar disorder, and schizophrenia. However, unlike other medical specialties, psychiatry does not routinely use tools like brain scans to diagnose or monitor these disorders. There are several reasons why brain imaging techniques have not become a standard part of psychiatric practice:
Brain scans have limited diagnostic utility
While research shows that mental illnesses are associated with changes in brain structure and function, these changes are not definitive biomarkers for specific disorders. Currently, there is no brain scan that can diagnose conditions like depression or schizophrenia with sufficient accuracy to be clinically useful. The brain changes associated with mental illness are often subtle and not present in all patients. Relying on brain scans alone would lead to many misdiagnoses. The Diagnostic and Statistical Manual of Mental Disorders (DSM) does not include any biological tests because none have yet proven accurate and reliable enough for diagnosis.
Lack of therapeutic relevance
A diagnosis in psychiatry needs to inform treatment decisions. Right now, seeing a brain scan does not change the psychiatrist’s approach to treating a patient. For example, knowing that a patient with depression has less gray matter volume in their hippocampus does not alter the recommendation for antidepressant medication and psychotherapy. The treatments are the same regardless of what subtleties emerge from brain scans. There are currently no psychiatric treatments that target specific brain changes identified through neuroimaging. Until brain scans lead to tangible improvements in care and outcomes, they will likely remain research tools rather than clinical tools.
Cost and accessibility barriers
Brain scans are expensive tests that require specialized equipment and personnel. Access is limited for many patients, as most clinics do not have brain scanners onsite. While costs are dropping over time, brain scans are still too expensive to perform routinely for psychiatric diagnosis and monitoring. Table 1 shows the approximate costs of common brain imaging techniques in the United States:
| Brain Imaging Technique | Approximate Cost |
|---|---|
| fMRI | $500-$3000 |
| PET | $1500-$5000 |
| SPECT | $800-$1400 |
Many psychiatrists do not have the equipment or funding to make brain scans part of their regular workflow. Until scans become more practical, most psychiatrists will rely on verbal questions, observations, and cognitive testing to evaluate and track mental health disorders.
Unclear benefit for patients
The clinical utility of routine brain scans in psychiatry remains unproven. There is insufficient evidence showing that using scans to diagnose and monitor patients leads to better outcomes. Exposing patients to tests that have unestablished benefits raises ethical concerns. Brain scans would likely add substantial cost and inconvenience without measurably improving diagnosis accuracy, treatment plans, or patient wellbeing. Until clinical trials demonstrate how brain scans can improve psychiatry, doctors will be hesitant to incorporate them into regular practice.
Concerns about overtesting and incidental findings
Ordering brain scans routinely would go against efforts to reduce unnecessary testing and overdiagnosis in medicine. Scans could uncover brain abnormalities unrelated to the mental health condition in question, creating dilemmas about how to interpret and manage incidental findings. Brain changes can occur naturally with aging or result from other factors like medications. Extensive testing risks overemphasizing benign variations and distracting from the core psychiatric evaluation.
Stigma concerns
The stigma surrounding mental illness is already a major barrier preventing people from seeking psychiatric help. Critics argue that brain scans could further promote the public perception of mental disorders as brain diseases, exacerbating stigma and hopelessness. Patients could feel overly labeled by scans purporting to show something wrong with their brain. At the same time, normal brain scans could mistakenly reinforce doubts some patients already have about the validity of their symptoms. More evidence is needed to determine how patients would respond psychologically to routine brain imaging in psychiatry.
Unresolved questions about what’s abnormal
There are still unresolved questions about how to distinguish normal from abnormal variations in brain structure and function. For example, there is overlap between patterns seen in healthy people and those with mental illness. And within a diagnosis like depression, brain changes can differ widely between patients. These complexities make it very difficult to define standardized measures and cutoffs. More research is needed to determine the parameters and patterns that could be considered biomarkers indicative of specific psychiatric diseases. Until then, most individual scans cannot be clearly categorized as normal or abnormal.
Conclusion
In summary, brain scans have not yet transitioned from research tools to clinical tools in psychiatry because of their limited diagnostic accuracy, lack of therapeutic impact, high costs, unclear benefit, potential harms, and unresolved questions about defining abnormality. Current expert guidelines do not recommend routine neuroimaging for psychiatric diagnosis or monitoring. While neuroscience is advancing our understanding of mental illness, brain scans remain impractical and unproven for most clinical applications. Until scans have better diagnostic power, therapeutic utility, and accessibility, psychiatric assessment will continue relying primarily on clinical interviewing, observation, and cognitive testing.