February 27, 2020
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Obsessive-compulsive symptoms may be linked to ‘impaired ability to rely on the past’

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Isaac Fradkin

Researchers have gained new insight into the cognitive and computational process underlying obsessive-compulsive symptoms. Specifically, patients with obsessive-compulsive disorder may distrust their past experience, resulting in increased indecisiveness, uncertainty and exploratory behaviors, according to study findings published in PLoS Computational Biology.

“In contrast to a common preconception, our study suggests that compulsions in OCD (eg, checking) are not necessarily an irrational repetition of purposeless behaviors,” Isaac Fradkin, PhD, of The Hebrew University of Jerusalem, told Healio Psychiatry. “Rather, they may be better understood as a rational reaction when the environment is perceived as highly unpredictable. Further, we found that obsessive-compulsive symptoms are related to an impaired ability to rely on the past (eg, the knowledge that I just turned off the lights) to infer the present and future (eg, assuming that the lights are off although I am no longer in the room).”

Researchers hypothesized that excessive information gathering and uncertainty about possible future events associated with obsessive-compulsive symptoms are caused by excessive uncertainty regarding state transitions — “a computational impairment in Bayesian inference” that inhibits use of the past to predict the present and future and results in oversensitivity to feedback. To investigate the relationship between obsessive-compulsive symptoms and transition uncertainty, Fradkin and colleagues employed a computational model including data of 58 individuals with varying levels of obsessive-compulsive symptoms. Participants completed a decision-making task in which they were asked to balance the weight they had assigned to prior experience with the weight assigned to more recent observations.

Using a set of equations to define participants’ decision-making process, the researchers found that participants who exhibited higher obsessive-compulsive symptoms were more likely to distrust past experience and thus perceive the environment as unpredictable. These participants also exhibited a pattern of behavior that potentially indicated a difficulty in relying on learned contingencies, with no evidence of perseverative behavior, the researchers wrote. Moreover, increased transition uncertainty reduced these participants’ ability to predict feedback for their decisions, which made them both more surprised by predictable feedback and less surprised by unpredictable feedback. However, the researchers found no evidence for excessive belief updating. “Importantly, our study examined the inability to rely on the past at the computational level (potentially reflecting the computations happening in the brain), and this does not necessarily reflect patients' conscious experience, which patients might find elusive and difficult to explain,” Fradkin told Healio Psychiatry. “Furthermore, understanding the cognitive and computational impairments that lead to the development of obsessive-compulsive symptoms might help develop novel treatments in the future.” – by Joe Gramigna

Disclosures: The authors report no relevant financial disclosures.