A surprising finding from a person with severe obsessive compulsive disorder has revealed an unexpected role for the brain’s reward system in diabetes. The finding may lead to a new understanding of the disease and novel treatments.
of the Academic Medical Center in Amsterdam, Netherlands, and her team made the finding while analysing people who have had electrodes surgically implanted deep in their brains to alleviate their OCD. These implants are offered to people who have failed to benefit from drugs, and whose OCD severely impacts their lives – for example, washing hands for more than 8 hours a day, or being unable to leave home without spending hours checkingÌýelectricity points are safe.
Such implants work by electrically stimulating a person’s nucleus accumbens, a region in the brain that is involved in feelings of reward. Boosting these feelings in people with severe OCD helps reduce compulsions to repeatedly perform particular tasks.
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But in one person, the implant seemed to have an extra, beneficial side-effect. This person had type-2 diabetes, but ever since he had his implant inserted five years ago, he has needed to take less insulin to control his blood sugar levels.
Dopamine hit
Detailed tests revealed that electrical brain stimulation somehow improved the ability of his body to remove excess sugar from his blood by between 7 to 10 per cent. When they looked at 14 others with OCD implants but who didn’t have diabetes, the team found that electrical stimulation also improved their blood sugar control.
The team suspects dopamine – the brain’s reward chemical – may explain the findings. Stimulation of the nucleus accumbens triggers the release of this chemical. The team believes that this then activates other brain and hormone signals that prompt the rest of the body to absorb more sugar.
In support of this, the team have found that stimulating mice to produce more brain dopamine causes them to remove sugar from their bloodstream more efficiently. When the team gave a drug that blocks dopamine to 10 people without diabetes or OCD, they found that this impaired the ability of their bodies to absorb excess sugar from the blood.
Inserting electrodes in the brain requires serious surgery and is unlikely to ever be appropriate for diabetes treatment. But the finding that dopamine plays a role in blood sugar control could lead to other new treatments for diabetes, including brain stimulation techniques that don’t require surgery.
Read more: Drug that boosts confidence in your own actions may help OCD
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