Intellectual and cognitive profiles in patients affected by schizophrenia

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.

A systematic review and narrative synthesis of data-driven studies in schizophrenia symptoms and cognitive deficits

“…The total sample size per study ranged from 62 to 8231 individuals irrespective of participants' diagnostic status. The reported clustering methods were Kmeans or non-hierarchical clustering analysis 21,53,55,[69][70][71][72][73][74][75][76] , Ward's method or hierarchical analysis [77][78][79][80][81][82][83] , K-means clustering and Ward's method 18,38,54,[84][85][86][87][88][89] , latent class or profile analysis 15,90,91 and two-step cluster analysis [92][93][94] . One study 95 identified clusters using a combination of clinical/empirical and statistical clustering methods.…”

“…One study 95 identified clusters using a combination of clinical/empirical and statistical clustering methods. The model selection criteria or similarity metrics were visual inspections of the dendrogram, Pearson correlation, (Table 2), 22 studies 18,38,53,54,70,71,75,76,[78][79][80][81][82]84,[86][87][88][90][91][92][93][94][95] reported cognitive clusters in patients with first-episode, stable or chronic schizophrenia with or without antipsychotics treatment and one study 54 reported cognitive clusters in unaffected siblings. Other studies investigated trajectories of negative symptoms 15,85 , positive symptoms 83 , positive and negative symptoms 21,69,77 in patients and positive and negative schizotypy in a nonclinical population 55,72,73,83 .…”

“…Of the 22 studies conducted on neurocognitive deficits, 17 studies 38,53,70,71,76,[78][79][80][81][82]84,90,[92][93][94][95] found three clusters, five studies 18,75,86,87,91 reported four clusters and one study 88 discovered five clusters among patients (Table 2d). Most studies assessed global cognitive function using a comprehensive neuropsychological test that included three to 18 cognitive subtests.…”

Implications of data-driven analyses for personalized therapy in psychosis: a systematic review of cluster- and trajectory-based modelling studies

“…101,102 In addition, poor cognitive impairment cluster(s) were predicted by age, gender, non-Caucasian ethnicity, low socioeconomic and educational status, poor premorbid adjustment, low premorbid and current IQ, early age of illness onset, long duration of illness, severe positive and negative symptoms, poor social cognition, high antipsychotics dosage, use of second generation antipsychotics, and poor functioning and poor quality of life. 32,37,65,66,[79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96] Siblings subgroups with impaired neurocognitive function were predicted by young age, low educational status, low IQ, poor premorbid adjustment, and severe positive schizotypy (Figure 4). 66 Figure 4: Schizophrenia spectrum circle illustrating predictors of symptomatic clusters.…”

The Use of Cognitive Screening in Pharmacotherapy Trials for Cognitive Impairment Associated With Schizophrenia

“…Schizophrenia is a heterogeneous disorder associated with varying clinical and cognitive profiles (6). Though the majority of patients with schizophrenia exhibit some general cognitive dysfunction compared to antecedent expectations, such as premorbid intelligence (7, 8), there is evidence that approximately a quarter of patients display cognitive performance comparable to healthy controls (9–12). Recent evidence has indicated that these “normally” performing patients are significantly less likely to exhibit changes in cognition when participating in CIAS trials (13, 14), suggesting that inclusion of these individuals may limit the scope to detect a pro-cognitive efficacy signal.…”