Cross-diagnostic cognitive heterogeneity in body dysmorphic disorder and obsessive-compulsive disorder

Previous research has indicated that body dysmorphic disorder (BDD) and obsessive-compulsive disorder (OCD) often demonstrate similar cognitive impairments across multiple domains. However, findings for both disorders have not consistently shown impaired cognition. As such, BDD and OCD might share an overlapping pattern of cognitive heterogeneity, characterised by subgroups with different cognitive profiles.

To evaluate this possibility, we compared 26 BDD, 24 OCD, and 26 healthy control participants on a comprehensive eight-domain cognitive battery. Then, cluster analysis was performed on the BDD and OCD participants' combined data to explore for cognitive subgroups.

No significant differences were found between the three groups' cognitive functioning, except for poorer visual learning in OCD relative to healthy controls. Cluster analysis produced two cognitive subgroups within the combined BDD and OCD data, characterised by intact cognition (52%) and broadly impaired cognition (48%). Each subgroup comprised both BDD and OCD participants, in similar proportions. The subgroups did not differ in clinical or demographic features.

Sample sizes were moderate. Future research should investigate clustering patterns both in larger groups and separately in BDD and OCD samples to determine replicability.

These findings suggest that BDD and OCD may involve similar patterns of cognitive heterogeneity, and further imply that individuals with either disorder can show a wide range of cognitive profiles, thus necessitating a nuanced approach to future cognitive research in BDD and OCD.