# The rollercoaster of obsessive-compulsive disorder: How chronotype and time of day affect behavioral inhibition in adults with OCD

## TL;DR

This study shows that OCD patients' ability to control compulsive behaviors varies with their natural sleep-wake patterns and time of day, suggesting treatment timing could improve outcomes.

## Contribution

The study reveals how chronotype and alertness interact to affect inhibitory control in OCD patients during symptom-provoking tasks.

## Key findings

- OCD patients had worse inhibitory control when exposed to symptom-provoking images compared to neutral ones.
- Inhibitory control improved during optimal alertness periods aligned with patients' chronotype.
- Heightened alertness may help break the cycle of OCD compulsions by improving inhibition.

## Abstract

Chronotype, a person's circadian preference, reflects individuals’ natural pattern of alertness levels throughout the day. It has been shown that chronotype contributes to within-day symptom fluctuations in obsessive-compulsive disorder (OCD). However, the underlying mechanism of this effect is not yet clear. Inhibitory control, an executive function crucial for suppressing unwanted behaviors and thoughts, is essential for managing OCD symptoms and is highly influenced by alertness levels. Hence, the current study investigated the impact of chronotype and time of day on inhibitory control in OCD patients, particularly in response to individually tailored symptom-provoking images, using a novel version of the stop signal task. Ninety-three treatment-seeking OCD patients completed an individually tailored Symptom-Provocation Stop-Signal Task, every morning and evening for four consecutive days. Chronotype was assessed using the Morningness-Eveningness Questionnaire (MEQ). Stop-signal reaction time (SSRT) was assessed for neutral and individually tailored symptom-provoking images separately. Patients exhibited longer SSRTs (worse inhibition) to symptom-provoking trials compared to neutral trials. Most importantly, chronotype and time of day significantly interacted to affect SSRTs in the symptom-provocation condition: A significant correlation was found between optimal alertness periods and improved inhibitory control in the symptom-provocation condition. Taken together, these results indicate that inhibitory control in OCD varies with chronotype and time of day. These findings suggest that aligning treatment sessions with patients' chronotype may enhance therapeutic outcomes and that heightening alertness—by increasing the chances of successful inhibition—might be a way to mitigate the vicious cycle of OCD.

•We investigated why chronotype and time of day influence symptom fluctuation in OCD.•Patients completed a tailored Symptom-Provocation Stop-Signal Task for four days.•OCD patients show worse inhibition to symptom-provoking vs. neutral stimuli.•Optimal alertness improves inhibition during symptom-provocation in OCD patients.•Heightened alertness could help break the vicious cycle of OCD compulsions.

We investigated why chronotype and time of day influence symptom fluctuation in OCD.

Patients completed a tailored Symptom-Provocation Stop-Signal Task for four days.

OCD patients show worse inhibition to symptom-provoking vs. neutral stimuli.

Optimal alertness improves inhibition during symptom-provocation in OCD patients.

Heightened alertness could help break the vicious cycle of OCD compulsions.