Cognitive Deficits in Obsessive-Compulsive Disorder

We read with interest a recent article by Sue R. Beers, Ph.D., and colleagues (1) examining neuropsychological functioning in children with obsessive-compulsive disorder (OCD). They found that children with OCD performed normally on a number of measures of executive functioning, including many previously shown to be impaired in adults with OCD. As noted by the authors, previous studies have documented that children with OCD already show abnormalities in frontal and striatal volumes in relation to comparison subjects. One explanation for these findings is that cognitive deficits emerge during the course of development in a manner that parallels the normal maturation of prefrontal systems.

Neuropsychological investigations of adults with OCD show impairment on complex measures of executive functioning and strategic memory. These problems may not be apparent in childhood because normal children do not have fully matured prefrontal networks and, consequently, show less developed executive functioning. Many executive and memory functions, including sustained attention, planning, problem solving, and semantic organization, show the greatest progression after age 12 (2, 3). There is also evidence that cognitive problems secondary to childhood brain injury may not become apparent until adolescence, when these abilities develop in normal children (4).

This concept might also be extended to the clinical phenomenology of OCD in different age groups. Comorbid illnesses, such as Tourette’s syndrome and attention deficit hyperactivity disorder, often appear years before the onset of actual OCD symptoms (5). In these cases, the emergence of OCD symptoms closely parallels the normal development of frontal lobe systems and executive functioning. The symptomatic expression of OCD also differs in children and adults, with children showing higher rates of compulsive rituals without clearly delineated obsessions. It is possible that a certain level of frontal system development is actually necessary to manifest some characteristic symptoms of OCD. For example, albeit dysfunctional, the capacity to obsess may require adequate working memory to maintain thoughts continually in awareness.

For these reasons, some neuropsychological and clinical symptoms of OCD may not emerge until critical prefrontal systems mature—perhaps not until adolescence or later. We applaud this interesting work by Dr. Beers and colleagues. Future investigations following such well-characterized cohorts longitudinally may clarify the way in which cognitive deficits and clinical symptoms of OCD evolve over the course of development.