Neuropsychological testing provides increasing evidence that certain memory deficits might play an essential role in the emergence of doubts and, as a result, in perpetuating checkers’ rituals. Another account of doubting implicates metacognitive factors, such as confidence in memory. The present study examined mnestic functioning and self-perception of memory ability in a group of 27 nondepressed patients with obsessive-compulsive disorder (OCD) and 27 normal controls. All patients met DSM-IV and ICD-10 criteria for OCD, displayed prominent behavioral checking rituals and had to show a score on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) of at least 16. Significant deficits in intermediate (Lern- und Gedächtnistest; LGT-3) and immediate (Corsi Block-Tapping Test) nonverbal memory were identified in the patients with OCD compared to normal controls. Contrary to predictions, OCD patients also showed a significant deficit in general memory and verbal memory (LGT-3). With respect to metacognition, OCD patients reported less confidence in their memories than controls. These findings suggest that obsessional doubt reflects a deficit in memory as well as a deficit in memory confidence. Depending on which dysfunction predominates, different therapeutic procedures seem to be required.

Seventy-four patients who met DSM-III-R criteria for obsessive compulsive disorder (OCD) were studied in a prospective follow-up study in order to investigate course and prognosis of OCD with or without comorbid depressive symptomatology. Subjects were examined three times: at admission (baseline), 6 months later (follow-up 1) and 12 months after follow-up 1 (follow-up 2). At admission, 51 (72.9%) OCD patients were assessed as depressive by the Hamilton Depression Scale score. Between admission and follow-up 1, all patients received behavior therapy and a serotonin reuptake inhibitor, between follow-up 1 and follow-up 2 they received different kinds of treatment in order to maximize therapeutic effects. A 25 % Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score reduction from admission to follow-up 2 and in addition, a total Y-BOCS score of below 16 at follow-up 2 was defined as ‘good prognosis course’. The results obtained showed that OCD patients who followed a good prognosis course, showed no significant depressive symptomatology at follow-up 2 (p = 0.001). These results imply that patients with a diagnosis of OCD may present depression at admission and/or follow-up 1; however, if OC symptomatology decreases longitudinally, depressive symptoms disappear too. We may assume that OCD is dominant over depression, and it seems that a comorbid depression does not have any major influence on the prognosis of OCD.