Correlation between prospective memory and quality of life in patients with schizophrenia

Abstract

Objective To compare the damage degrees between time- and event-based prospective memory (PM) tasks in schizophrenic patients, and to explore the relationship between prospective memory and mental symptoms, between individual and social function, and between quality of life and medical history. Methods On the basis of Einstein's and McDaniel's dual task paradigm, 56 schizophrenic patients and 56 normal subjects were tested using graphical material prospective memory tasks, including time-based prospective memory task (TBPM) and event-based prospective memory task (EBPM). Results The patients were worse than the normal in the TBPM task for the correct number of prospective tasks, the correct number of ongoing tasks, and the response time of ongoing tasks [6.50(4.00) vs. 8.00(1.50), 61.00(19.75) vs.70.50(10.00), 1 603.50(975.00)ms vs. 1 196.00(429.50)ms, all P<0.01]. In the EBPM task, the correct number of prospective tasks, the response time of prospective tasks, the correct number of ongoing tasks, and the response time of ongoing tasks were worse in the patients than in the normal [4.00(5.75)vs. 6.00(4.00), 2 903.00(3 168.50)ms vs. 1 206.00(1 396.00)ms, 73.00(14.25) vs. 77.00(4.00), 1 852.00(732.75)ms vs. 1 354.00(398.75)ms, all P<0.01]. Spearman correlation analysis showed a significant negative correlation between the total score of the PANSS scale (47.75±8.24) and the ongoing task in EBPM (r=-0.35, P<0.01). The correct numbers of TBPM and EBPM prospective tasks in the patients were significantly positively correlated with the PSP scale score (71.70±22.79)(r=54, P<0.01; r=36, P<0.01). The correct number and the response time of TBPM prospective tasks, the correct number and the response time of TBPM ongoing tasks, and the correct number and the response time of EBPM ongoing tasks in the patients were significantly correlated with the SQLS scale score (23.07±12.89)(r=-0.35, P<0.01; r=0.48, P<0.01; r=-0.78, P<0.05; r=0.69, P<0.05; r=-0.35, P<0.01; r=0.58, P<0.01). Conclusion Prospective memory impairment exists in patients with schizophrenia; prospective memory ability in patients with schizophrenia is closely related to individual social function and quality of life. Key words: Schizophrenia; Prospective memory; Individual and social function; Quality of life