- Published: June 5, 2015
One of the many obstacles facing juries throughout the history of the legal system has been the question of expert testimony. It has long been the practice of both prosecution and defense to hire professionals from any field to testify in hopes of tilting the case in favor of their client. However, deciding whether evidence presented by these individuals is actually “expert” frequently proves challenging. In the case of determining whether a defendant has a mental illness, juries have historically had to rely on the often-vague characterizations found in the DSM-IV and “expert” psychiatrists to interpret them.
Fortunately, breakthroughs in fMRI scanning may turn the tables on this highly subjective system and give juries something much more concrete to use. Over the past decade, many mental illnesses have been reliably localized by consistently abnormal hemodynamic response in various brain areas. This has not only allowed observers the ability to see general categories of mental disorder, but even to distinguish between various degrees and small variations within an individual disease’s spectrum. The most recent breakthrough happened this past September for Postpartum Depression, while researchers have been progressively better at localizing Bipolar Disorder and Schizophrenia.
It is my hope that an increased use of such fMRI evidence in the courtroom will lend jurors a much clearer view of mental illness, without the need of subjective interpretations from expert testimony. While these middlemen may understand the nature of mental illness, many lay people do not recognize that a mental disorder indicates structural abnormalities in the brain, not simple weakness in character. While our imaging technology may not be advanced enough to locate mental abnormalities in the same way that an X-ray would locate a fractured hip, I think that fMRIs will be continue to increase in accuracy and relevance to major courtroom issues.