title: Cluster analysis of cognitive deficits may mark heterogeneity in schizophrenia in terms of outcome and response to treatment.
abstract: Cognitive impairments are central to schizophrenia, but their clinical utility for tagging heterogeneity in lifetime outcome and response to treatment is not conclusive. By exploiting four cognitive domains consistently showing large deficits in studies, we tested whether cluster analysis would define separate subsets of patients and then whether the disease heterogeneity marked by these clusters would be related to lifetime outcome and response to treatment. A total of 112 schizophrenia patients completed a neuropsychological evaluation. The PANSS, GAF-S and GAF-F were rated at the onset and endpoint of the illness trajectory. A blind judgment of the lifetime response to treatment was made. The first cluster presented near-normal cognitive performance. Two other clusters of severely impaired patients were identified: one generally impaired in the four cognitive domains and another selectively impaired in visual episodic memory and processing speed, each relating to a different lifetime evolution of disease and treatment response. Although the two impaired clusters were clinically indistinguishable in symptom severity and functioning at disease onset, patients with selective cognitive impairments demonstrated better improvement at outcome, whereas the generally impaired patients were more likely to be treatment refractory. The findings have implications for the management of patients and for clinical trials since particular combinations of cognitive deficits in patients would influence their treatment response.
authors.affiliation: Centre de recherche, Institut universitaire en santé mentale de Québec, 2601, chemin de la Canardière (F-4500), Quebec, QC, G1J 2G3, Canada.
authors.forename: Elsa
authors.initials: E
authors.lastname: Gilbert
authors.forename: Chantal
authors.initials: C
authors.lastname: Mérette
authors.forename: Valérie
authors.initials: V
authors.lastname: Jomphe
authors.forename: Claudia
authors.initials: C
authors.lastname: Emond
authors.forename: Nancie
authors.initials: N
authors.lastname: Rouleau
authors.forename: Roch-Hugo
authors.initials: RH
authors.lastname: Bouchard
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Roy
authors.forename: Thomas
authors.initials: T
authors.lastname: Paccalet
authors.forename: Michel
authors.initials: M
authors.lastname: Maziade
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001288:Attention; D016000:Cluster Analysis; D003072:Cognition Disorders / Q000188:drug therapy* / Q000209:etiology*; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D011597:Psychomotor Performance; D012559:Schizophrenia / Q000150:complications* / Q000188:drug therapy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents