Cognitive symptoms are common in functional neurological disorder (FND), yet evidence of impaired neurocognitive test performance is variable. We aimed to assess self-reported cognitive symptoms, neurocognitive test performance, and metacognitive confidence in patients with functional seizures (FS) and functional motor symptoms (FMS).

Participants with FS (n = 50) and FMS (n = 50) were compared to age- and gender-matched healthy controls (HC, n = 50), and clinical controls with depression and/or anxiety disorders (CC, n = 50). The Cambridge Neuropsychological Test Automated Battery was used to examine response speed, working memory, executive functions, and social–emotional processing, with subjective confidence rated for each test. Intellectual functioning, performance validity, and self-reported cognitive symptoms were also assessed.

The FND groups reported elevated cognitive symptoms compared to HC and CC (p-values<0.001). Impaired performance was demonstrated in both FND groups on tests of sustained attention (p-values = 0.03- < 0.001) and set-shifting (p-values = 0.01–0.001). Performance validity was comparable between groups (p = 0.64). The FND groups reported reduced post-diction confidence for sustained attention (p < 0.001). Executive performance deficits correlated with reduced test-specific confidence in FS/FMS (p-values = 0.02- < 0.001). In FMS, post-diction confidence for sustained attention performance correlated negatively with cognitive symptoms (p = 0.002). Cognitive symptoms were associated with psychological/physical symptom load, quality-of-life, and/or general functioning in FND and CC groups (p-values = 0.04- < 0.001).

Patients with FS and FMS displayed localized deficits on tests of executive functioning, with reduced domain-specific metacognitive confidence, alongside significant cognitive symptoms. These neurocognitive features were associated with poorer clinical status, warranting interventions targeting cognitive control and/or cognitive symptoms in everyday life.