- Mental disorders are the No. 1 cause of disability for people ages 15-45 in the developed world.
- There are 33,000 suicides every year in the US—twice as many suicides as homicides.
- The life expectancy of people with serious mental illnesses like schizophrenia, 56, is 25 years earlier than the population at large.
- There are three times as many people with serious mental illness in jails and prisons than in hospitals.
These statistics define where we are in the field, said Thomas Insel, director of the National Institute of Mental Health and a member of the Dana Alliance for Brain Initiatives. But the field will be transformed in coming decades, he argues, as what we learn from genetics, brain science, and behavior come together to change how we diagnose, treat, and think about mental illness.
Insel wrote a commentary on the topic in this week’s issue of JAMA; yesterday he elaborated on his ideas during a media briefing discussing the special issue, which focuses on mental illness.
For example, advances in genetics have led to the discovery of structural variations in the genome. In mental illnesses like schizophrenia, autism, bipolar disorder, OCD, and ADHD, researchers have found hundreds of common variations—deletions or duplications in the genetic code—that have “completely changed the way we think about genetics in psychiatric disease,” he said.
These variations—all associated with neurodevelopmental genes—“could not be associated with a single illness even in the same family,” said Insel; the same variation could indicate schizophrenia for one person, and autism for another. But they could point to a more general risk for mental illness.
Discoveries about brain circuitry also may change how we may view disorders. Much mental illness is associated with the developing brain—the age of onset peaks in the teen years, when the brain’s grey matter is undergoing a “pruning effect” and becoming more efficient. Some disorders might be described as “poor pruning.”
For example, it may be that people likely to develop schizophrenia lose too many synapses during this period, Insel suggested. He hopes that by 2020, we can detect schizophrenia before psychosis begins. “We are going to shift the curve and get earlier in diagnosis and treatment,” intervening when people have risk factors but before they have symptoms.
This may lead to a change in the way diseases are defined. “We have been locked into presentation,” said Insel, citing the way the DSM characterizes diseases by symptoms, not underlying causes. “Most of medicine has moved beyond that. We want to add all the things we can’t see,” like genetics and imaging.
In a decade, predicts Insel, “We will have entirely different names and ways of thinking about disorders.”