How people with OCD get stuck in unwanted behavioural loops

Key points:

• A study from the University of New South Wales, published this week, has revealed that teenagers with obsessive-compulsive disorder experience trouble with making decisions

• Teenaged participants completed decision-making tasks whilst inside a magnetic resonance imaging, commonly referred to as MRI, scanner

• Scientists hope that uncovering the biological basis for OCD may reduce stigma and dispel public scepticism surrounding the legitimacy of the condition

Over 750,000 Australians live with or have experienced obsessive-compulsive disorder, yet the condition is often subject to scrutiny and stigma in the public eye. However, new research from the University of New South Wales found that the condition may have biological roots that are related to decision-making in an area of the brain called the orbitofrontal cortex.

The UNSW researchers aimed to build upon previous academic work to understand the biological basis of OCD, which could lead to the development of new treatments. They focused on adolescents in the study, due to the fact that OCD typically develops in childhood or adolescence.

Approximately one in 50 Australian children experience OCD, with the peak age of onset occurring around 11 and 18 years of age.

Examiners found that the group of 20 adolescents with OCD had a hard time making decisions and controlling their behaviour during a decision-making task while being scanned in an MRI machine, compared to the group of 21 healthy adolescents.

The decision-making tasks included playing a computer game to tilt a digital vending machine in exchange for food ‘rewards.’ However, the ‘value’ of the food rewards would be adjusted through simulated bugs crawling across the food, for instance.

Dr Iain Perkes, the first author of the study that was published in Biological Psychiatry Global Open Science, explained that people with OCD get stuck in loops of unwanted thoughts and behaviours.

“These repetitive actions, obsessions and compulsions aren’t completely under the control of someone with OCD. Otherwise, they would simply choose not to do them,” Dr Perkes said.

“So, there was good reason to think that those decision-making mechanisms in the brain go awry in the case of OCD.

“We wanted to see how changing the value of the reward would change the choice of action for healthy young people, versus young people with OCD.”

Adolescents with OCD struggled to make choices and control their behaviour to gain food rewards. In addition, when the value of the food rewards was reduced, this had little influence on their behaviour during the tasks.

“People with OCD experience difficulties using reward signals to guide their choices in an adaptive way. Those behavioural difficulties are associated with changes in the brain,” Dr Perkes added.

According to Dr Perkes, people with OCD are sometimes invalidated by others when they struggle with unwanted thoughts and behaviours — stemming from the orbitofrontal cortex, which is a part of the brain responsible for decision-making.

In the experiment, specific areas of the cortex were hyperactive and hypoactive in participants with OCD when completing the tasks, which aligns with previous tests conducted with rats.

“This is strong evidence that these mechanisms have a core role in the development of OCD,” Dr Perkes said.

“It shifts the dialogue from ‘just pull your socks up, work harder’ to ‘there are changes in the brain, that’s a real health condition.’

“We know that for one-third of people living with OCD, they don’t respond to first-line treatments.”

These findings could lead to more targeted transcranial magnetic stimulation, which is sometimes used to target nerve cells in the brain to treat OCD.

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