post by Bill Gardner
Jesse Singal writes in the Daily Beast about our recent article, "Discovery of blood transcriptomic markers for depression in animal models and pilot validation in subjects with early-onset major depression," in Translational Psychiatry (also discussed here, here, and here; and see also commenter Will on the last link).
Singal quotes Michele Goodwin, a law professor and bioethicist at the University of Minnesota.
If diagnosing depression shifts from a mostly interview-based process to a more quantitative, blood-based one, she said, the potential for overdiagnosis—and overmedication—will grow, especially in vulnerable populations.
This is especially troubling given the United States’ track record in this area, Goodwin said.
“It has to be understood within the context of our culture,” she said. “In a culture that’s so quick to medicate on everything, including on cases where it might appear quite problematic that we would choose medicine over other alternatives, then there might be cause for some concern.”
Goodwin cited the example of K-12 schooling in the United States, where children are often routed into special-ed programs based not on specific learning disabilities, but on behavioral problems. The system overwhelmingly lumps poor kids, and particularly poor minority kids, into that category. And from there they are often put on medication at a very young age.
“We’re a nation of shortcuts,” Goodwin said. “So however we think about what ideally we would want to do, the reality is that we are in a space of doing something different.”
First, I must restate that we did not announce a blood test for early-onset depression. What we found was that a gene expression profile based on factors identified from animal models and other data was able to discriminate between depressed and non-depressed adolescents. This is a first step, but it needs to be both reflined and replicated in a larger sample before the finding has any clinical application. Unfortunately, many preliminary findings like ours do not pan out. I am sure that Singal and Goodwin both get this.
Next, the concerns that Goodwin raises about over-medication of disadvantaged children are well-grounded. With another group of colleagues, I am beginning health services research on the use of atypical antipsychotics in the foster care population, where there is great concern that children may be medicated too frequently with these drugs.
Having said this, I am puzzled why Goodwin believes that having a biological test would exacerbate this problem. It may be that we are currently over-diagnosing several conditions. (I think this is likely, at least for some populations; other populations are likely under-diagnosed.) But this problem of mis-diagnosis is occurring already with interview-based methods. Assuming we were able to validate an assay, having both interview and physiological data should make diagnosis more rather than less accurate.
Our goal in this research is to develop a tool that would help clinicians identify those children who would be most likely to benefit from mental health care. This care could be either psychotherapy or anti-depressant medication -- there is nothing about a positive blood test that implies that a medication is the necessary treatment. An accurate blood assay should not only find new cases of children who need mental health care but also reduce inappropriate or excessive treatment.