Transforming our understanding of the causes and treatment of mental disorders

After a huge rise in the death rate from coronary heart disease was discovered in the 50s and 60s, science resolved to do something about it, and it did. “Had we not changed the trajectory of that disease, we would have had a million additional people dying today,” said Tom Insel  MD, Director of the National Institute of Mental Health, in a Monday afternoon plenary at the 42^nd National Council Conference in Chicago.

And, he added, while research has made great strides in treating HIV-AIDS, breast cancer, and other diseases, four decades of research into the causes, treatment, and prevention of mental illness has yielded relatively little to date.  Despite these efforts, Insel said that with regard to mental illness, diagnosis depends on observations, detection is late, and our ability to predict its onset is poor.  Treatment is based on trial and error and no definitive cures have been found.

“The bottom line,” he said, “is that there has been no decrease in the incidence or impact of mental disorders to date.”  Citing annual statistics that say mental disorders account for twice the burden in years lost to illness of any other disease, and more deaths (36,000 suicides annually) in the US than either traffic accidents, AIDS, or homicide, Insel suggested that it is time for a renewed effort to take on and transform the nation’s understanding about the causes and treatment of mental disorders.  

Recent innovations in mental heath research

Insel stated that recent research demonstrates that mental disorders are “complex circuit disorders” of the brain, far more complex than simplistic explanations of chemical imbalances.  Viewing the complex circuitry of the brain is now possible thanks to efforts like the human connectome project, an effort to map the circuits of the brain.

While the precise causes of mental disorders are not known, Insel said that evidence suggests that their causes are found in a complicated mix of genetic risk factors whose expression is shaped by experience during the pre-natal development of a child. “The genetics play out, but experience shapes the expression of the genes,” he noted. Unlike other genes associated with physical disorders, the genes for mental disorders appear to map to the expression of mood, cognition, and regulation in the brain.

Their unusual development and early onset make mental disorders relatively unique among major diseases, he suggested Unlike cancer, heart disease, diabetes and many other serious illnesses that are usually associated with adulthood, mental disorders are developmental disorders, with a reported onset of half of all cases by age 14. 

Using the human connectome map, Insel said, “This complex map reminds us that depression, for example, is not one thing—it is enormously heterogenous disorder.” Using tools like this, Insel asserts that scientists are able to “dissect a disorder into its component parts.”  By studying each part, “we begin to see that meds work in some areas, cognitive therapy in others, and other therapies, such as deep brain stimulation, in other areas.” 

Recent advances like these, he suggested give us a “very different picture of depression than the ones we’ve been accustomed to hearing—that it is anger turned inward, a sense of hopelessness or helplessness, or a simple chemical reaction.”