Age-related practice effects across longitudinal neuropsychological assessments in older people with schizophrenia.
The relationship between aging and practice effects on longitudinal neuropsychological assessments was investigated in middle-aged and older people with schizophrenia and healthy controls.


METHODS
Older people with schizophrenia (n = 107; M age = 56.1) and age-comparable nonpsychiatric controls (n = 107; M age = 57.7) were scheduled to receive annual assessments on a comprehensive battery of neuropsychological tests for an average of 2.5 years (range 11 months to 4 years). Mixed-model analyses were used to separately examine the effects of practice and age on test performance.


RESULTS
Number of prior assessments (practice) was associated with significant performance improvement across assessments, whereas older age was associated with significant decline in performance. The groups did not differ significantly in extent of age-related cognitive decline, but a three-way interaction among group, age, and practice was found, such that greater age-related decline in practice effects were found for older people with schizophrenia relative to nonpsychiatric participants.


CONCLUSIONS
This study did not find any evidence of neurodegenerative age-related decline in neuropsychological abilities in middle-aged and older people with schizophrenia, but older age was associated with diminished ability to benefit from repeated exposure to cognitive tasks in people with schizophrenia. Cognitive impairment in schizophrenia may combine with cognitive decline associated with normal aging to reduce practice effects in older patients. These findings have important implications for the design of studies examining the longitudinal trajectory of cognitive functioning across the life span of people with schizophrenia, as well as clinical trials that attempt to demonstrate cognitive enhancement in these individuals.
Granholm
Eric
E
VA San Diego Healthcare System (116B), 3350 La Jolla Village Drive, San Diego, CA 92161, USA. egranholm@ucsd.edu
Link
Peter
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Fish
Scott
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Kraemer
Helena
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Jeste
Dilip
D
D000328:Adult; D000368:Aged; D000375:Aging / Q000523:psychology*; D014150:Antipsychotic Agents / Q000627:therapeutic use; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007858:Learning; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009483:Neuropsychological Tests; D011214:Practice, Psychological; D011618:Psychotic Disorders / Q000188:drug therapy / Q000503:physiopathology*; D012016:Reference Values; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000188:drug therapy / Q000503:physiopathology*; D012565:Schizophrenic Psychology
D014150:Antipsychotic Agents