Exploring cognitive heterogeneity in first-episode psychosis: What cluster analysis can reveal.
Variable outcomes in first-episode psychosis (FEP) are partly attributable to heterogeneity in cognitive functioning. To aid identification of those likely to have poorer or better outcomes, we examined whether purported cognitive profiles identified through use of cluster analysis in chronic schizophrenia were evident in FEP. We also aimed to assess whether there was a relationship between cognitive profile and factors independent of the solution, providing external validation that the cognitive profiles represented distinct subgroups. Ward's method hierarchical cluster analysis, verified by a k-means cluster solution, was performed using data obtained from a cognitive test battery administered to 128 participants aged 15-25 years. Four cognitive profiles were identified. A continuity element was evident; participants in cluster four were more cognitively impaired compared to participants in cluster three, who appeared more cognitively intact. Clusters one and two were distinguishable across measures of attention and working memory and visual recognition memory, most likely reflecting sample specific patterns of deficit. Participants in cluster four had significantly lower premorbid and current IQ and higher negative symptoms compared to participants in cluster three. The distinct levels and patterns of cognition found in chronic schizophrenia cohorts are also evident across diagnostic categories in FEP.
Department of Psychology and Counselling, La Trobe University, Melbourne, Victoria 3086, Australia.
Maree P
MP
Reser
Orygen, The National Centre of Excellence in Youth Mental Health, 35 Poplar Road, Parkville, Victoria 3053, Australia; Centre for Youth Mental Health, The University of Melbourne, Victoria 3010, Australia.
Kelly A
KA
Allott
Orygen, The National Centre of Excellence in Youth Mental Health, 35 Poplar Road, Parkville, Victoria 3053, Australia; Centre for Youth Mental Health, The University of Melbourne, Victoria 3010, Australia.
Eóin
E
Killackey
Department of Psychology and Counselling, La Trobe University, Melbourne, Victoria 3086, Australia.
John
J
Farhall
Orygen, The National Centre of Excellence in Youth Mental Health, 35 Poplar Road, Parkville, Victoria 3053, Australia; Centre for Youth Mental Health, The University of Melbourne, Victoria 3010, Australia. Electronic address: smcotton@unimelb.edu.au.
Susan M
SM
Cotton
D000293:Adolescent; D000328:Adult; D001288:Attention; D016000:Cluster Analysis; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D011618:Psychotic Disorders / Q000523:psychology*; D012565:Schizophrenic Psychology; D055815:Young Adult
Cognitive impairment; Cognitive subtypes