May 1st, 2013

New study links mental disorders to common gene

Though a new study links five mental disorders to a common gene, it’s too early to tell whether it could affect how practitioners care for patients.

Usually viewed as distinct disorders, autism, attention deficit hyperactivity, bipolar disorder, major depression and schizophrenia actually share a genetic effect, according to a recent National Institutes of Health-funded study published Feb. 28, 2013, in The Lancet. Even so, lead researcher, Jordan Smoller, M.D., of Massachusetts General Hospital in Boston, says that though the long-term effects of the study might influence how psychologists diagnose and treat disorders, any short-term or immediate implications are limited.

“The genetic findings (from this study) do point to some biological pathways where we could get clues for possible new treatments,” says Smoller. “These might be more biologically related than we have originally thought and knowing how related these disorders are could be helpful over time.”

Smoller and a team of doctors and colleagues from the Cross-Disorder Group of the Psychiatric Genomics Consortium analyzed the five key disorders as if they were the same illness. They screened more than 33,332 patients with all five disorders and drew on samples from other mega-analyses, linking two genes that regulate the flow of calcium into cells.

“The hope is that (the study) better informs the underlying shared basis for these disorders and their structures,” Smoller says. “Their boundaries might not be as sharp after all.”

But not all psychologists are convinced and remain cautious, pointing to external influences as equally important factors for diagnosis. Sara Rosenquist, Ph.D., a clinical health psychologist, questions the usefulness of the study and believes it may be “a red herring that deepens a commitment to this cultural catalogue we call of the DSM and export all over the world as a way of expanding the market for our pharmaceuticals.”

“Scratch the surface very hard and you’ll find that we all share genes in common,” Rosenquist says. “Without reference to the social and cultural context in which they occur, mental ‘illness’ as a construct and the tome that supports our constructs are meaningless.”

In fact, mental disorders are universally classified not on the basis of underlying neural or genetic pathology, but on behavioral criteria, according to Bryan Auday, Ph.D., professor of psychology at Gordon College in Wenham, Mass..

“Though I support this direction (of research), it will not resolve or put to rest the historical debate regarding how we classify mental disorders,” Auday says. “Understanding the abnormal genetic similarities among the disorders is still light-years away from understanding how the genes interact and are eventually expressed as behavioral psychiatric conditions.”

While some psychologists acknowledge Smoller’s study won’t significantly alter how they treat these disorders, they admit such research could contribute to a holistic approach to problems and treatment solutions. All agree that more specific information could provide greater understanding for what’s actually going wrong biologically.

“Epigenetics, the interaction of behavior and genetics, gets much more interesting with many more treatment implications for psychologists and for physicians,” says Colleen Redding, Ph.D, research professor at the University of Rhode Island. “(And) it is certainly in need of more research.”

Smoller agrees. “These five are still different disorders, but here’s some evidence that suggests they might actually have some common link, and although we found variables to all five, their effects are still modest.”

By Jo Kadlecek

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