Obsessional slowness in obsessive-compulsive disorder: identifying characteristics and comorbidities in a clinical sample

BACKGROUND: Obsessional slowness (OS) is characterised by debilitating motor slowness during initiation and completion of daily tasks such as washing, dressing, eating or walking. Yet, the clinical features of OS are still poorly understood. METHODS: This study aimed to delineate demographics, comorbid disorders and obsessive-compulsive symptoms (OCS) associated with OS. Cross sectional data from 667 OCD outpatients aged 9–82years (M=37.86, SD=12.78) who underwent comprehensive standardised assessments administered by trained clinicians were analysed. Participants with (n=189) and without (n=478) OS were compared and contrasted. RESULTS: Logistic regression revealed that being single, having tics and displaying higher severity of aggression, contamination, symmetry and hoarding symptoms significantly predicted participants having OS. CONCLUSIONS: This is the largest-scale descriptive study of OS, which also provides preliminary evidence that OS may be a more severe form of OCD. Further empirical validation of these findings is required, and future research should focus on developing OS assessment.Key Points This was the first large-scale descriptive study of obsessional slowness (OS), that provided preliminary evidence for an OS phenotype within obsessive-compulsive disorder OS is associated with increased severity of aggression, contamination, symmetry and hoarding obsessive-compulsive symptoms Individuals with OS are more likely to have comorbid tics, suggesting that there may be underlying motor factors contributing to this condition Future research would benefit from collecting both qualitative and quantitative data when assessing OS.