Working memory change with age in patients with schizophrenia

Objective: To explore the working memory changing with age and correlations between clinical symptoms and working memory in patients with schizophrenia.Methods: Working memory were measured using digit span test and space span test in 123 inpatients with schizophrenia who met the Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition(DSM-Ⅳ) criteria and 124 normal controls.The clinical symptoms in patients were assessed with the Positive and Negative Syndrome Scale in schizophrenia.Results: Except backward score [(5.2±2.5) vs.(5.8±2.4),P0.05],both composite score [(15.8±4.3) vs.(17.2±4.3),P0.05],forward score [(10.6±2.5) vs.(11.3±2.5),P0.05] of digit span and composite score [(12.0±4.4) vs.(14.5±3.9),P0.01],forward score [(6.3±2.1) vs.(7.2±2.2),P0.01],backward score [(6.2±2.4) vs.(7.6±1.9),P0.01] of space span in patients with schizophrenia were significant worse than that of controls.The composite score,forward score and backward score of digit span test were significant negatively related with age both in patients and in normals(r=-0.21~0.37,Ps0.05).To test the interactive effects between age and group on working memory,both patients and normal controls were divided into two subgoups with older(45 years) and younger(≤45 years) subgroup respectively.There were age and group main effects both on digit span performance and space span performance(P0.05),but no interactive effects were revealed between age and group(P0.05).There were significant negative correlations between composite score,backward score of digit span test and PANSS total score in patients with schizophrenia(r=-0.22,-0.24,Ps0.05).The composite score,forward score,backward score of digit span test and composite score,backward score of space span test were significant negatively related with PANSS negative score in patients with schizophrenia.(r=-0.22——0.26,Ps0.05).Conclusion: It suggests that patients with schizophrenia experience a non-disease specific pattern of verbal working memory declining with increasing age,which is similar to normal controls.Working memory performance is negatively correlated with negative symptoms in patients with schizophrenia.