Barney Carroll: the conscience of psychiatry

A pioneer in biological psychiatry, more recently Bernard Carroll (‘‘Barney’’) became a withering critic of its compromised ethics and corruption by industry. Shortly before his death, he helped prepare this obituary—his last chance to help correct the perverse incentives that too often influence the conduct and reporting of scientific research.

Barney’s scientific contribution to psychiatric research was to introduce neuroendocrine techniques. He independently discovered the value of the dexamethasone suppression test (DST) as a biomarker of melancholia—the classic, biologically driven subtype of depression. This was the first, and remains one of very few, biomarkers in psychiatry. Barney’s 1981 paper on the DST was among the most highly cited papers in psychiatry. Its impact was immediate, with many replications and extensions.

Another of Barney’s enduring contributions was to educate colleagues in the discipline of proper clinical decision making. He clarified the Bayesian principle that context counts—that is, prior conditional probabilities greatly influence the utility of any clinical feature or laboratory test in making a diagnosis. Throughout medicine, biomarkers and clinical diagnostic features perform with much greater utility in high risk groups than in general populations.

Barney criticised the Diagnostic and Statistical Manual for innumerate failures to clarify the performance of diagnostic criteria and pointed out that candidate biomarkers often outperformed accepted symptomatic diagnostic criteria.