Declarative and procedural learning in individuals with subclinical obsessive-compulsive symptoms.

Previous neuropsychological research suggests that psychometrically defined subclinical obsessive-compulsive (OC) individuals perform worse than non-OC controls on specific tests of executive functioning. This study aimed to extend these findings by comparing the performance of 25 subclinical OC and 28 non-OC control subjects on measures of declarative learning (Rey Auditory Verbal Learning Test), motor procedural learning (star maze), spatial problem solving (single administration of the 3-disk version of the Tower of Hanoi; TH3), and "cognitive" procedural learning (repeated administrations of the 4-disk version of the Tower of Hanoi; TH4). In addition, the subjects were administered measures of general intelligence, anxiety and depression. No between-group differences were observed on measures of declarative and motor procedural learning. Subclinical OC subjects needed significantly more moves than controls to solve TH3, suggesting poorer spatial problem solving ability. A significant group x trial interaction on the TH4 suggested reduced cognitive skill acquisition in the subclinical OC group. However, performance on TH3 and TH4 was significantly correlated in the OC group but not in the control group, suggesting that the suboptimal acquisition of cognitive skills among subclinical OC subjects is more likely to be related to inefficient spatial problem solving strategies than to a cognitive procedural learning deficit per se. These results replicate and expand upon previous findings and support a dimensional model of Obsessive-Compulsive Disorder.