Are failures to suppress obsessive-intrusive thoughts associated with working memory?

BACKGROUND AND OBJECTIVES: Obsessive compulsive disorder (OCD) is characterised by repeated attempts to suppress obsessive-intrusive thoughts (OITs). Nonclinical individuals also regularly engage in thought suppression. Attempts to suppress OITs are often unsuccessful and there is wide variation in suppression abilities across nonclinical and clinical samples. Understanding the mechanisms that explain variations in suppression abilities could enhance our understanding of OCD. This study aimed to investigate one potential mechanism - working memory - using a comprehensive thought suppression task.

METHODS: Eighty-three nonclinical participants completed a computerized thought dismissibility task (in which they replaced an obsessive-intrusive thought with a neutral thought), and a computerized working memory task. Participants also completed measures of OCD and negative mood.

RESULTS: None of the suppression variables (OIT frequency, mean OIT duration, mean latency to return, total OIT duration) were correlated with working memory capacity. Obsessive-compulsive symptoms were correlated with total OIT duration, but the relationship was not significant after controlling for negative mood.

LIMITATIONS: The thought dismissibility task does not account for differences in motivation to suppress OITs. The sample was non-clinical and mostly female.

CONCLUSION: An individual's ability to suppress OITs is not associated with their working memory capacity, suggesting poor working memory does not explain persistent OITs in individuals with OCD.