Beyond the DSM: Thomas Insel and Understanding Mental Illness
You may have heard that several days ago, Thomas Insel, head of the NIMH, announced in a blog post, Transforming Diagnosis, that "the NIMH will be re-orienting its research away from DSM categories."
He went on to say that: "We will be supporting research projects that look across current categories - or sub-divide current categories - to begin to develop a better system."
Thus: "Studies of biomarkers for 'depression' might begin by looking across many disorders with anhedonia or emotional appraisal bias or psychomotor retardation to understand the circuitry underlying these symptoms."
Dr Insel's announcement comes three weeks prior to the publication of the DSM-5, which will supersede the DSM-IV. Dr Insel is no fan of the DSM. In his blog, he refers to how people describe the manual as a "bible in its field," but at best, he says, it is a "dictionary, creating a set of labels and defining each." According to Dr Insel: "Patients with mental disorders deserve better."
To those who have been following Dr Insel and the NIMH over the years, the announcement should come as no surprise. While technically a psychiatrist, Dr Insel's research background is in the neurobiology of complex social behaviors. His best known work has to do with the monogamous behavior in the prairie vole vs the promiscuous behavior of its close cousin, the montane vole. Both animals have oxytocin and vasopressin receptors distributed throughout the brain, but the circuitry is different.
Oxytocin and vasopressin are peptides that act as both hormones and neurotransmitters. Commonly referred to as the "love hormones," among many other things, these two chemicals appear to induce a state that is the very opposite of depression and anxiety,
The prairie vole is a dramatic example of how brain circuits can influence and sometimes even determine behavior. In a Ted Talk in January this year, entitled Toward a New Understanding of Mental Illness, Dr Insel asked his audience to rethink "mental" disorders and "behavioral" disorders as "brain" disorders, but not in the simplistic and misleading chemical imbalance of the brain sense. Instead, he said, we are talking about an organ of "surreal complexity" which we are only just beginning to understand how to even study it.
With regard to illnesses such as depression, says Dr Insel, we may be talking about traffic jams or detours or problems with the way things are connected. With brain disorders, we are finding that there are changes in the brain years before we can observe behavioral changes. In his talk, Dr Insel makes reference to the old diagnostic categories, but in his blog he is very clearly looking to new ways to explain how the brain mediates behavior.
In 2008, the NIMH released a strategic plan that included developing, for research purposes, "new ways of classifying mental disorders based on dimensions of observable behavior and neurobiological measures." This included delving deeper into how neural circuits - plus genes and environment - influence behavior. From this evolved the "NIMH Research Domain Criteria (RDoC)."
According to the NIMH: "Rather than starting with an illness definition and seeking its neurobiological underpinnings, RDoC begins with current understandings of behavior-brain relationships and links them to clinical phenomena."
In other words, the DSM has it back-to-front, starting with behavior symptoms and working backward. This can only lead to a very biased view of observing the brain. In June 2011, the NIMH released a third RDoC draft in which it outlined its five domains.
The first two include "negative valence systems" and "positive valence systems." In other words, what makes us feel fearful and threatened vs what makes us feel motivated and rewarded?
The third has to do with "cognition," including: attention, perception, working memory, and cognitive control.
The fourth concerns "systems for social processes," including: affiliation and attachment, social communication, perception and understanding of self, and perception and understanding of others.
Finally, we have "arousal and regulatory systems," including arousal, circadian rhythms, and sleep and wakefulness.
The NIMH emphasized that these domains are starting points only and are not to be regarded as set in concrete. The purpose is to foster more coherent research, but I would suggest that we can employ these domains right now as a personal exercise in looking at our own behavior, and of developing a better understanding of our own illness. You may have noticed, already, that bipolar cuts across all of these domains. But what does YOUR bipolar look like? Are you mostly stuck in "negative valence," for instance, or is arousal and sleep your big problem?
Maybe what looks like bipolar isn't even bipolar. Who knows? As for the DSM, my recommendation stays the same: Use it as a rough guide. Depression and mania and psychosis and anxiety certainly exist. But these states viewed in simplistic isolation hardly tell the whole story. We need a better understanding. You don't have to wait for researchers to come up with definitive brain scans and gene studies. You can ask your own questions right now.