The association between dimensions of obsessive-compulsive disorder and eating disorders: A systematic review

Obsessive-compulsive disorder (OCD) and eating disorders (ED) are highly co-occurrent. While the association between OCD and ED has long been studied, there is a lack of review on how OCD is related to ED at a symptom level. The current systematic review aimed to examine how OCD symptoms relate to ED. A protocol was registered on PROSPERO. PsycINFO, EMBASE, and MEDLINE databases were searched. Fifty-one studies, mostly cross-sectional, with 15,072 participants met the inclusion criteria. Studies focusing specifically on general obsessions and compulsions revealed that obsessions tend to be more prevalent among individuals with ED, and there was more evidence supporting their association with ED symptoms. OCD subtypes were categorized based on the assessment scale used. The symmetry/exactness and ordering/arranging dimensions of the Yale-Brown Obsessive-Compulsive Scale; the doubting and slowness dimensions of the Maudsley Obsessive-Compulsive Inventory; the obsessing and ordering dimension of the Obsessive-Compulsive Inventory; obsessional and the impulses dimensions of the Padua Inventory, and the cleaning/washing dimension of other scales showed more notable associations with ED symptoms compared to other dimensions. Also, obsessive beliefs were found to be related to ED symptoms. The included studies demonstrated that OCD symptoms are linked to eating disorders and behaviours through both cognitive and behavioural components. Particularly, the cognitive aspect of OCD, characterized by obsessions and obsessive beliefs, may play an important role in comorbidity with ED. This review emphasizes the importance of considering symptom-level association between OCD and ED to improve treatment outcomes. • OCD and ED may demonstrate a symptom-level association. • OCD may be associated ED through obsessions and compulsions. • The cognitive aspect of OCD may underlie its comorbidity with ED.