In a review article for this month’s American Journal of Psychiatry, Daniel Weinberger and Eugenia Radulescu from John Hopkins University push back against the overreliance on MRI scans in recent psychiatric studies. While acknowledging that they both have contributed to this type of research in the past, the authors warn that “findings” from these studies “pose a serious risk of misinforming our colleagues and our patients.”
The search for brain structures or “abnormalities” underlying mental health problems began in the early 1900s, with scientists carefully examining the brains of deceased patients. The authors point out that many of these early studies yielded findings, “but none withstood the test of time and more critical analysis of the subject.” By the end of the century, however, advances in technology made is possible for researchers to attempt to study the brain in living patients, setting off a “renaissance of neuroanatomical investigations.”
“It is almost impossible to pick up a current psychiatric journal and not see a study of anatomical measurement made on MRI scans comparing patients with a psychiatric diagnosis with healthy subjects,” they write.
The authors express concern that so many of these studies are claiming to discover biological differences in the brains of psychiatric patients that “it has become research lore that structural changes in the brain are characteristic of many psychiatric disorders and are likely clues to primary neurobiology.”
“These various findings are routinely referred to as ‘cortical thinning,’ ‘atrophy,’ ‘tissue loss,’ or worse, and they are assumed to be insights into the underlying nature of these conditions.”
These findings and assumptions are not supported by the science, according to the authors, as any “differences” found in the brain scans may simply be artifacts of a secondary symptom with no relation at all to the patient’s mental health. In addition, data from MRI studies can routinely be compromised by several confounders, including head motion and breathing, smoking, body weight, metabolic variations, medical comorbidities, psychoactive drugs, alcohol use, and even mental states.
“The overarching purpose of this cautionary note is to encourage a discussion about a widely and tacitly recognized, though mostly ignored, “inconvenient” truth: that conventional MRI does not allow us to make firm inferences about the primary biology of mental disorders and that we need to acknowledge this as a starting point in realizing the full value of MRI studies in psychiatry.”
Weinberger, D. R., & Radulescu, E. (2015). Finding the elusive psychiatric “lesion” with 21st-century neuroanatomy: a note of caution. American Journal of Psychiatry, appi-ajp. (Abstract)