People may forget to bring keys when go out, or forget to attend an important appointment in their daily lives, these are examples of prospective memory (PM) failure. PM is the ability to remember to complete a previously formed intention. PM failures may sometimes cause serious consequences. PM has been found to be impaired in patients with schizophrenia, and such impairment was significantly correlated with their clinical symptoms and social functioning. However, PM seems not to be very responsive to conventional medication. Therefore, it is important to improve PM performance in patients with schizophrenia.

Recent empirical findings suggest that implementation intention (II) may improve PM performance in healthy and clinical populations including schizophrenia patients. II is an encoding strategy which can facilitate achievement of goals. However, these empirical findings have been exclusively limited to a number of issues including that most of the prior studies used short-term instruction manipulation form of II and conducted in the laboratory, whether it is effective in daily life PM task is not clear. In addition, it is suggested that if we could improve PM performance, social functioning may also be improved at the same time, but this has not been proved yet. Moreover, whether II training has long-term effect on PM and social functioning is not known.

 
To clarify the above issues, Drs. Ya Wang and Raymond Chan from the Neuropsychology and Applied Cognitive Neuroscience (NACN) Lab, CAS Key Laboratory of Mental Health, Institute of Psychology working with their collaborators to examine whether II can improve PM in patients with schizophrenia using a randomly assigned clinical trial. They recruited 42 community schizophrenia patients, and randomly assigned them to a II group and a control group, with 21 patients each. The two groups were well matched on demographic or clinical variables. The II group received II training in addition to medication. The training was conducted in small groups, with 6-8 participants in each group. There were 10 sessions and each session lasted about ninety minutes. There were two sessions every week. During the training, patients were trained to use the II technique in their daily life independently. The training included five modules: the first module provided psycho-social education on PM and PM difficulty in daily life and introduced the II strategy; the second module trained verbal component of II; the third module trained the visual imagination component; the fourth module trained the use of combination of II strategy in simulated scenarios; the last module trained the use of combination of strategy in daily settings. The control group only received medication treatment. Outcome measures included computer PM task, phone call task (daily PM task), and performance-based social functioning task. Both II and control groups received baseline, post-training and 3-month follow-up assessments.

The II group was found to show improvement in both computer and daily PM tasks compared to the control group, and the improvement remained significant at follow-up assessment. In addition, the II group also showed improvement in working ability and total score of social functioning. Results showed that patients with lower education, cognitive functions and baseline PM performance demonstrated larger PM improvement after training.

Taken together, this study shows that II training can improve PM performance in schizophrenia patients, and the improvement can be maintained after three months. Social functioning can also be improved through the training on PM. II may be an effective training that can be applied to clinical settings for patients with poor PM performances.

This study was supported by National Science Foundation of China, Beijing Brain and Cognition Funding and China Scholarship Council.

This paper is now available online in Schizophrenia Research,

Chen, T., Liu, L.L., Cui, J.F., Li, Y., Qin, X.J., Tao, S.L., Neumann, D.L., Shum, D.H.K., Cheung, E.F.C., Wang Y*, Chan, R.C.K. (in press). Implementation intention training for prospective memory in schizophrenia: A 3-month follow-up study. Schizophrenia Research, https://doi.org/10.1016/j.schres.2018.10.015

Contact:

LIU Chen

Institute of Psychology, Chinese Academy of Science

liuc@psych.ac.cn