From The National Institute of Mental Health
By Thomas Insel, M.D.
December 13, 2013
It’s time again for the year’s ten best from NIMH.
A year that included a 16-day government shutdown and a 5.2 percent sequester also saw some outstanding scientific breakthroughs and historic changes in policy. Befitting the complexity of the problems, many of the breakthroughs were not individually reported findings but the cumulative results of several groups contributing different pieces of the puzzle. And some of the most historic policy changes are just launching so their impact is unclear. Paring a lengthy list down to “ten best” is both difficult and unsatisfying, but here goes.
10.) Nobel Prize—This year’s Nobel Prize in Physiology or Medicine (and Lasker Award) recognized NIMH grantee Thomas Südhof for his discoveries of how neurotransmitters are released from the pre-synaptic terminal. Südhof and his colleagues described the molecular machines that allow vesicles to empty their contents into the synapse and then re-form to collect more neurotransmitters. This process is critical for neurons to communicate efficiently.
Recently, Südhof’s work on the post-synaptic compartment has revealed a new world of molecules important for translating these biochemical messages. The genes for many of these protein families (i.e., shanks, neuroligins, neurexins, etc.) are emerging as leading risk candidates for autism and schizophrenia, giving us a new vocabulary for the molecular basis of mental disorders. (1)
9.) Beyond Magic Bullets—Several important new trends emerged this year in non-pharmacological treatments, sometimes from pharmaceutical companies. In April, a Nature commentary that included authors from the pharmaceutical giant GSK described “electroceuticals,” heralding a new era in treatment development focusing on devices to deliver electric signals rather than drugs to alter the activity of neurotransmitters in the brain.
Neuromodulation, arguably a better term than electroceuticals, had already been gaining traction with treatment of depression using deep brain stimulation and direct current stimulation. This year neuromodulation was introduced for anorexia nervosa. But neuromodulation was also extended to include approaches beyond electrical stimulation. In September, the cover headline of Nature—“Game Changer”—referred to a study by Adam Gazzaley and colleagues on the impact of cognitive training with NeuroRacer, a video game for enhancement of cognitive control. Not only did older adults (60 – 85 years old) trained on this game surpass performance of untrained 20-year-olds, cognitive enhancement generalized to working memory and other forms of cognitive control, with improvements persisting 6 months later. Cognitive training changed local brain activity as well.
The key concept: if mental disorders are brain circuit disorders, then successful treatments need to tune circuits with precision. Chemicals may be less precise than electrical or cognitive interventions that target specific circuits. (2,3,4)
8.) Organoids—It’s been 6 years since the first report of induced pluripotent stem cells (iPSCs). These are cells derived from mature skin cells, induced to become undifferentiated stem cells in a dish, and then differentiated to form mature cells like neurons or heart muscle cells. It’s been a year since this work was awarded the 2012 Nobel Prize in Physiology or Medicine. The excitement of this new technique was the potential to take cells from an individual with a disorder and either regenerate new cells in vitro (imagine new dopamine cells for someone with Parkinson’s disease) or recapitulate the disorder in vitro to define its development and screen for new treatments.
This year, there were some remarkable reports of using iPSCs to explore the altered development of neurons in children with rare forms of autism. But if autism and mental illnesses are circuit disorders or “connectopathies,” how can individual cells teach us about the altered connections? Amazingly, according to a team from the Austrian Academy of Sciences in Vienna, when neurons are grown in a dish, they self-assemble into circuits that resemble the normal cortex. These “organoids” are not “mini-brains” capable of consciousness but they are functional enough to permit the study of connections. It now appears that iPSCs could be a powerful tool to study circuit disorders. (5,6,7)
7.) DSM-5 and RDoC—For NIMH, probably the year’s most oft-quoted statement was my April blog post about transforming diagnosis. Referring to the pending release of the DSM-5, I said, “Patients with mental disorders deserve better.” To many, this was interpreted as a critique of mainstream psychiatry. In truth, I was complaining that we in the research community have failed to provide the objective measures for diagnosis present in every other area of medicine. The Research Domain Criteria (RDoC) project aims to do just that, by using biological, cognitive, and social information to build more precise classifiers for each patient.
RDoC is not a diagnostic system. At this point it is simply a framework for organizing the data. But it is a promise from the NIMH to get beyond diagnostic categories based only on symptoms. Why is this important? For brain disorders, symptoms are generally a late manifestation of a years-long brain process. In medicine, early detection and early intervention have often been the best ways to improve outcomes. RDoC is a first step towards achieving these goals with mental disorders. (8,9)
6.) EP3—A year that began with concerns about school shootings and mental illness saw more mass shootings, many of them connected to serious mental illness (SMI). For this unfortunate reason, there was more media attention on mental illness this year than any time in recent memory. The number of articles about “mental illness” in the New York Times in 2013 were more than double the average of the previous five years. Among the many recurring themes—access to weapons, access to treatment, incarceration—one prominent one was the need for earlier detection and treatment for SMI.
The Early Prediction and Prevention of Psychosis (EP3) program, launched this year at NIMH, is an example of efforts to answer that need. Building on the success of the Recovery After Initial Schizophrenia Episode (RAISE) project, which was implemented this year in New York and Maryland, EP3 will focus on tools for the prodrome, that period prior to psychosis when symptoms are just beginning to emerge and may be most treatable. New studies will build on results from the North American Prodrome Longitudinal Study (NAPLS), just completing 10 years of critical research to develop ways to identify individuals who are at risk for an initial psychotic episode. With a series of new funding announcements and with the success of RAISE and NAPLS, NIMH made EP3 its signature program this year. (10,11)
5.) Psychiatric Genetics—In 2003,Science magazine named the identification of genes for mental illness as its #2 breakthrough of the year (just behind confirmation of the existence of dark energy in the cosmos). It has taken another decade to deliver results that are statistically significant and clearly reproducible. For schizophrenia there are now 128 genetic associations, all common variants found across the genome. None of these alone accounts for much of the risk, but groups of these “hits” point to specific biological pathways.
For autism, there are many rare variants emerging, many of these “de novo” or spontaneous mutations not found in other family members. These mutations seem to be most common in children with both autism and intellectual disability. Studies that have looked across disorders find some common genomic associations, with some findings across childhood disorders and others across adult disorders, irrespective of diagnosis. Before concluding anything about the significance of these cross-disorder findings, it will be important to understand the actual variation (which gene is involved) and the functional role, if any, of the variant. (12,13)
4.) Brain Exceptionalism—For me, 2013 will be the year when we began to realize how much the brain differs from other organs. We already knew that cells in the brain express (translate into protein) more of the genome and use more energy than any other organ. But two discoveries this year really made the case for the human brain as not only the most mysterious but the most exceptional of organs. Leveraging new tools for single cell biology, scientists working with Rusty Gage at the Salk Institute and Ira Hall at the University of Virginia reported that the brain has its own genome, with abundant and sometimes profound variation not found in other tissues. In human frontal cortex, they report as many as 41 percent of cells having at least one large mutation, with a million DNA bases either duplicated or deleted. These are mutations not seen in blood cells (which have been the basis for all psychiatric genetic studies) or in neurons elsewhere in the brain.
Equally surprising, the brain epigenome also appears unique. The epigenome is a complex of molecules that coat the DNA helix, “silencing” parts of the genome to ensure that certain genes are not translated. The entire DNA strand consists of only four bases: cytosine, guanine, adenine, and thymine. Whereas in most cells in the body silencing occurs where cytosine and guanine are adjacent, brain cells follow a different set of rules with all the base pairs involved. This means that the mechanisms by which experience influence biology are completely different in brain cells compared to blood cells or liver cells. The lesson is that we cannot use peripheral cells to know what is happening in the brain. (14,15)
3.) CLARITY—It may be an inelegant acronym but the results are utterly beautiful. CLARITY = Clear Lipid-exchanged Anatomically Rigid Imaging/immunostaining-compatible Tissue hYdrogel. By replacing the brain’s fat with a clear gel, CLARITY turns the opaque and impermeable brain into a transparent and porous structure. Most important, the hydrogel holds the brain’s anatomy intact. And because the hydrogel is permeable, the brain can be stained to localize proteins, neurotransmitters, and genes at a high resolution.
Unlike other recent breakthroughs in neuroanatomy, this one can be used in human brains. And unlike virtually all neuroanatomy of the past century, CLARITY is 3-dimensional. Flying through the tissue in 3-D allows the first comprehensive view of how cells and processes are arrayed across the entire brain. Karl Deisseroth earlier developed optogenetics as a revolutionary tool for studying brain circuits in behaving animals. This time his lab has revolutionized how we will look at the brain post-mortem. (16)
2.) BRAIN—On April 2nd, President Obama in the East Room announced the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative. The speech should be read by everyone with a stake in brain research or brain disorders. Calling BRAIN the “next great American project,” he challenged a broad scientific community to explore the brain as we had once explored space. BRAIN will involve several government research agencies as well as several private sector partners. And it complements a large brain project underway in the European Union and projects being developed in Israel, Japan, China, and elsewhere.
This global interest in neuroscience reflects both the growing awareness of the cost of brain disorders and the growing recognition that success in the 21st century will depend on a “brain economy” rather than a “brawn economy.” The U.S. BRAIN initiative will launch in 2014 with $110M, of which $40M will be from NIH. Funding announcements for the first wave of NIH projects will be released this month. (17)
1.) Parity—My guess is that in terms of mental health issues, history will remember 2013 not for a scientific finding but for a long overdue policy change: mental health parity. While the Mental Health Parity and Addiction Equity Act was signed into law in October 2008, the final rule providing the guidance to implement this law was only released in November 2013. Most important, the Affordable Care Act, signed into law in 2010, affirmed mental health care as an “essential benefit.” As a result, mental health care must be provided in all health care plans and the provision of care for mental disorders must be on a par with other medical disorders (i.e., same co-pays, deductibles, certification requirements).
When you add to these changes the removal of exclusions for pre-existing conditions, the extension of coverage to offspring until age 26, and in some states the expansion of Medicaid, you can see that this is really the most far-reaching change in mental health care since the Community Mental Health Act 50 years ago. And this is coming at an important time. Over the summer, the Global Burden of Disease project reported out on 291 medical disorders, updating its 1990 report with 2010 data. The new report finds mental illness and substance abuse disorders to be the leading source of years lost to disability, with the burden of illness from this group of disorders increasing 37 percent since 1990. Depression and anxiety were the largest contributors among the 20 mental and substance abuse disorders, accounting for 55 percent of the DALYs (disability adjusted life years—a composite measure of disability and premature mortality).
There are many questions about how parity will reduce DALYs: Who will provide the care? What will it cost? Where will mental health care be delivered? What is the dose and duration of psychosocial treatments that will be covered? None of these questions will be answered in 2013, but going forward NIMH can ensure that the best science informs this historic change. (18,19)
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