Differential relationship between neurological and cognitive dysfunction in first episode psychosis patients and in healthy individuals

The minor neurological and cognitive deficits consistently reported in psychoses may reflect the same underlying brain dysfunction. Still, even in healthy individuals minor neurological abnormalities are associated with worse cognitive function. Therefore, establishing which neurological and cognitive deficits are specific to psychosis is essential to inform the pathophysiology of this disorder. We evaluated a large epidemiological sample of patients with first episode psychosis (n = 242) and a population-based sample of healthy individuals (n = 155), as part of the AESOP study. We examined neurological soft signs using the Neurological Evaluation Scale (Buchanan and Heinrichs, 1989), and generalized and specific cognitive deficits (memory; verbal abilities; attention, concentration and mental speed; executive functions and working memory; language; visual constructual/perceptual abilities). In patients, more neurological signs across all subscales were associated with worse general cognitive function, while in controls this was only present for sensory integration and sequencing signs. Furthermore, in patients, but not in healthy individuals, more sensory integrative signs were associated with deficits in specific cognitive domains, such as memory, verbal abilities, language, visual/perceptual, executive function (p ranging < 0.001–0.002); sequencing signs with language, executive function, and attention (p < 0.001–0.004); and motor signs with poorer verbal abilities (p = 0.001). These findings indicate the presence of specific associations between neurological and cognitive deficits in psychosis that are distinct from those of healthy individuals.