Short-term verbal memory deficits in patients with obsessive-compulsive disorder

Recent neuropsychological studies have found deficits in the verbal memory of patients with obsessive-compulsive disorder. Difficulties in using organizational strategies were presumed to be the cause. Preceding studies did not look closely at their ability of feature detection of stimuli. Efficiency in feature detection is crucial to use the attributes or feature of stimuli as a clue in memory tasks. We examined verbal memory deficit and the ability of feature detection in Japanese patients with obsessive-compulsive disorder. We administered Iddon et al.'s verbal strategy task to 16 patients with obsessive-compulsive disorder and 16 healthy controls. The feature of Iddon et al.'s task was to include a phase that showed subjects the semantic structure of the task and timed each subject's analysis of the organization. Patients with obsessive-compulsive disorder were slower to classify stimuli words into semantic categories than were healthy controls. They recalled and recognized significantly fewer words than did healthy controls. In recall tasks, they used less organizational strategy than did healthy controls. Patients with obsessive-compulsive disorder were slower to analyze features of stimuli words than were healthy controls. This slowness possibly contributes to impaired memory performances that patients showed during the encoding process, since the efficient use of organizational strategies in limited time is difficult for them.