Prospective memory and its correlates and predictors in schizophrenia: an extension of previous findings.
BACKGROUND
Prospective memory (PM) is the ability to remember to do something in the future without explicit prompts. Extending the number of subjects and the scope of our previously published study, this investigation examined the relationship between PM and socio-demographic and clinical factors, activities of daily living (ADL) and frontal lobe functions in patients with chronic schizophrenia.


METHODS
One hundred and ten Chinese schizophrenia patients, 60 from the previous study and 50 additional patients recruited for this study, and 110 matched healthy comparison subjects (HC) formed the study sample. Patients' clinical condition and activity of daily living were evaluated with the Brief Psychiatric Rating Scale (BPRS) and the Functional Needs Assessment (FNA). Time- and event-based PM tasks and three tests of prefrontal lobe functions (Design Fluency Test [DFT], Tower of London [TOL], Wisconsin Card Sorting Test [WCST]) were also administered.


RESULTS
Patients' level of ADL and psychopathology were not associated with PM functions and only anticholinergic medications (ACM) showed a significant negative correlational relationship with PM tasks. Confirming the findings of the previous study, patients performed significantly more poorly on all two PM tasks than HC. Performance on time-based PM task significantly correlated with age, education level and DFT in HC and with age, DFT, TOL and WCST in patients. Patients' performance on the event-based PM correlated with DFT and one measure of WCST. In patients, TOL and age predicted the performance on time-based PM task; DFT and WCST predicted the event-based task.


CONCLUSIONS
Involving a large sample of patients with matched controls, this study confirmed that PM is impaired in chronic schizophrenia. Deficient PM functions were related to prefrontal lobe dysfunction in both HC and patients but not to the patients' clinical condition, nor did they significantly affect ADL. ACMs determined certain aspects of PM.
Ungvari
Gabor S
GS
Department of Psychiatry, Chinese University of Hong Kong, Hong Kong, China.
Xiang
Yu-Tao
YT
Tang
Wai-Kwong
WK
Shum
David
D
D000293:Adolescent; D000328:Adult; D010054:Brief Psychiatric Rating Scale; D016022:Case-Control Studies; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards; D011237:Predictive Value of Tests; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013223:Statistics as Topic; D055815:Young Adult