A cognitive profile of body dysmorphic disorder: an investigation using the WAIS-IV

The cognitive-behavioral model of body dysmorphic disorder (BDD) implicates impaired cognition; yet existing evidence of cognitive impairment in the disorder is often inconsistent. To date, cognitive performance in BDD has not been measured utilizing the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV), a gold standard cognitive assessment in clinical settings. Accordingly, this study compared WAIS-IV performance between individuals with BDD and healthy controls.

Participants included 59 BDD patients and 56 controls. Cognitive performance was evaluated via the WAIS-IV, and clinical characteristics of the BDD group were examined via multiple clinician and self-report questionnaires.

The BDD group demonstrated significantly poorer performance compared to the control group in the WAIS-IV index and subtests that reflect processing speed abilities (Processing Speed Index: d = -0.55, 95% CI [-0.92, -0.18], Symbol Search: d = -0.70, 95% CI [-1.07, -0.32], Coding: d = -0.79, 95% CI [-1.17, -0.41]), yet other indices were not significantly different. These impairments were not correlated with anxiety or BDD-YBOCS symptom severity. Reduced overall cognitive performance was primarily driven by impairments in processing speed.

The study suggests that in BDD, processing speed is notably lower than other index scores, falling in the low average range. This may reflect difficulties with rapid visual processing, attention to detail, or motor speed. Performance in domains reflective of reasoning and verbal functioning were unimpaired relative to controls. This selective cognitive pattern in BDD may be driven by increased cognitive load associated with perfectionistic traits. This has clinical implications for cognitive-behavioral treatment.