In people with OCD, actions are at odds with beliefs

September 28, 2017, Cell Press
In people with OCD, actions are at odds with beliefs

The repeated behaviors that characterize obsessive-compulsive disorder are a manifestation of an underlying brain dysfunction that is not yet well understood. Now, in a study appearing on September 28 in the journal Neuron, scientists in the UK report the use of a mathematical model that they say will help them get at the root of what causes OCD. They find that people with OCD develop an internal, accurate sense of how things work but do not use it to guide behavior.

"This study shows that the actions of people with OCD often don't take into account what they've already learned," says senior author Benedetto De Martino , principal investigator of the Brain Decision Modelling Laboratory at University College London. The study was led by graduate students Matilde Vaghi and Fabrice Luyckx.

The researchers were able to measure the degree to which beliefs and action were dissociated from one another, and they found that the degree of uncoupling could predict the severity of OCD symptoms. "This was very surprising to me," De Martino adds. "It's the first time anyone has been able to calculate the degree of dissociation and show that it correlates with the severity of the disease."

De Martino's lab is focused on developing a mechanistic understanding of the connection between confidence and action. Specifically, his group looks at how certainty guides the decisions that we make. For example, if you are certain that it will rain, you will take an umbrella with you. "But we suspect that in people with OCD, this link is broken," he explains. "Someone with OCD will tell you that they know their hands are clean, but nevertheless they can't stop washing them. Two things that are normally linked together—confidence and action—have become uncoupled."

A video of the 'game' that the participants played during the experiment. Credit: Vaghi and Luyckx et al.

To study the connection, the investigators developed a test to measure this phenomenon. Forty-nine volunteers (24 with OCD and 25 matched controls) were recruited to play a video game in which they had to catch coin-like objects in a bucket. After several trials, both sets of participants were able to state with confidence where they thought the coins were coming from. Yet while the healthy participants were able to set their buckets based on that belief, those with OCD continued to second guess themselves, disregarding the confidence they felt and chasing every coin by constantly moving their buckets around.

This type of study belongs to a relatively new field of research called computational psychiatry, which is focused on developing mathematical models to understand the defects in the brain that lead to detrimental behaviors. "Medicine today is very much about decoding the mechanisms in the body," De Martino says. "When we are talking about something like a heart valve, that's a mechanical part that can be clearly understood. But the brain is a computational device that has no mechanical parts, so we need to develop mathematical tools to understand what happens when something goes wrong with a brain computation and generates a disease."

"This model not only gives us greater insight into OCD, but also into the normal, healthy as well," says De Martino. "Just as studying people with lesions in the hippocampus has historically taught us about the inner workings of memory, studying people with OCD can give us new insights into how beliefs and actions are linked."

He adds that once such tools are developed, they are likely to be useful in developing new approaches for diagnosis, which could lead to early detection and early intervention. "This would be a game-changer in the field," he concludes.

Explore further: How our brains integrate online reviews into our own product preferences

More information: Neuron, Vaghi and Luyckx et al.: "Compulsivity reveals a novel dissociation between action and confidence" http://www.cell.com/neuron/fulltext/S0896-6273(17)30841-3 , DOI: 10.1016/j.neuron.2017.09.006

Related Stories

How our brains integrate online reviews into our own product preferences

May 31, 2017
UCL researchers have identified how the human brain integrates social information when a person decides how much they like something, by studying how user reviews on Amazon influence how people rate the products.

Common cerebral white matter abnormalities found in children with autistic traits

September 6, 2017
Structural abnormalities in the brain's white matter match up consistently with the severity of autistic symptoms not only in children with autism spectrum disorder (ASD), but also, to some degree, in those with attention-deficit/hyperactivity ...

Brain study shows why some people are more in tune with what they want

December 9, 2012
Wellcome Trust researchers have discovered how the brain assesses confidence in its decisions. The findings explain why some people have better insight into their choices than others.

Behavioral therapy increases connectivity in brains of people with OCD

September 19, 2017
UCLA researchers report that people with obsessive-compulsive disorder, when treated with a special form of talk therapy, demonstrate distinct changes in their brains as well as improvement in their symptoms.

Mathematical tools improve theory and prediction in psychiatry

August 24, 2017
Recent years have seen an explosion in the use of mathematical models to integrate insights emerging from studies of the brain and behavior. This approach has been used to develop new theoretical perspectives that can enrich ...

The effects of weak magnetic fields on cancer cells and other aspects of biology

April 23, 2012
We are surrounded by a constantly changing magnetic field, be it the Earth's or those emanating from devices, such as cell phones. Carlos Martino, an assistant professor at the University of Nevada, Reno, is interested in ...

Recommended for you

Researchers investigate changes in white matter in mice exposed to low-frequency brain stimulation

June 19, 2018
A team of researchers at the University of Oregon has learned more about the mechanism involved in mouse brain white matter changes as it responds to stimulation. In their paper published in Proceedings of the National Academy ...

Left, right and center: mapping emotion in the brain

June 19, 2018
According to a radical new model of emotion in the brain, a current treatment for the most common mental health problems could be ineffective or even detrimental to about 50 percent of the population.

Cell type and environment influence protein turnover in the brain

June 19, 2018
Scientists have revealed that protein molecules in the brain are broken down and replaced at different rates, depending on where in the brain they are.

Often overlooked glial cell is key to learning and memory

June 18, 2018
Glial cells surround neurons and provide support—not unlike hospital staff and nurses supporting doctors to keep operations running smoothly. These often-overlooked cells, which include oligodendrocytes and astrocytes, ...

Electrically stimulating the brain may restore movement after stroke

June 18, 2018
UC San Francisco scientists have improved mobility in rats that had experienced debilitating strokes by using electrical stimulation to restore a distinctive pattern of brain cell activity associated with efficient movement. ...

Neuroscientists map brain's response to cold touch

June 18, 2018
Carnegie Mellon University neuroscientists have mapped the feeling of cool touch to the brain's insula in a mouse model. The findings, published in the June 15 issue of Journal of Comparative Neurology, provide an experimental ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

BubbaNicholson
1 / 5 (1) Oct 01, 2017
OCD and onychophagia can be treated effectively with 250mg of healthy adult male facial skin surface lipid pheromone p.o. It's basically due to a paternal facial skin surface pheromone deficiency. Beware the airborne fumes from the pheromone, however, as these are aversive and "emotionally toxic". Use fume hoods, respirators, fans, patient isolation for 40 days to avoid jealousy, etc.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.