Abstract
Intellectual abilities display high heterogeneity in patients with schizophrenia that might depend on the interaction among neurodevelopmental processes, environmental factors and neurocognitive decline. This study aimed to disentangle the interplay between intellectual level, cognitive status and each cognitive domain, with a focus on speed-related abilities, also including pre-morbid factors. In details, by means of cluster analysis, we identified both in global sample of 452 patients affected by schizophrenia and in a subsample with high pre-morbid functioning, different profiles based on current intellectual level and global cognitive status, analysing the distribution of deficits in each cognitive domains between groups. Then, through regression models, we analysed the contribution of speed-related domains and global cognitive profile to each other cognitive function. Considering the whole sample, results highlight three groups (high, medium and low cognitive level), while among patients with high pre-morbid level, the heterogeneity was best captured by two groups (high and medium level). Still, within each group, a small to high percentage of patients achieved normal score in neurocognitive abilities depending on the cluster they belong to. Speed of processing and psychomotor coordination resulted impaired in all clusters, even in patients with high pre-morbid functioning. The regression analyses revealed significant effects of both cognitive profile and speed-dependent domains on the other cognitive abilities. This study confirms, in a large sample, previous data about the heterogeneity of intellectual and neurocognitive functioning in schizophrenia and highlights the main role of speed-dependent neurocognitive functioning, also as an important target of rehabilitation.
