Schizophrenia, a type of chronic disabling mental illness, is associated with sever cognitive deficits. Prospective memory refers to the ability to remember to carry out intended actions in the future. Numerous studies showed that schizophrenia patients and individuals at high risk for schizophrenia manifested deficits in prospective memory. Moreover, the prospective memory difficulty among schizophrenia patients concurred with their poor medication management and social function. Those deficient functions may prevent schizophrenia patients from recovery and independent living, which cause burdens to care-givers and the society. Thus, it become urgently needed to intervene prospective memory in schizophrenia patients.
Implementation intentions, an encoding strategy to facilitate behaviors in the typical form of "if I encounter丫then I will do Z", has manifested robust effect in prospective memory. Notwithstanding, some issues still needed to be clarified. Firstly,previous studies adopting implementation intentions manipulation to improve prospective memory in schizophrenia patients typically just require patients to encode the instructions in less than _5 minutes before the experiments. However, the brief instruction manipulation and ignoring training participants to apply the techniques actively in daily fife may result in weak transfer effects as well as lasting effects. In addition, although some studies showed that prospective memory was correlated with medication management and social function among schizophrenia patients, no study examined whether the intervention for prospective memory in schizophrenia patients can improve medication management ability and social function. Moreover, it was unknown whether the implementation intention training can improve prospective memory, medication management ability and social function with lasting effects.
To answer the above questions, a total of 42 outpatients were recruited and randomly assigned to the implementation intentions (n=21)and the treatment as usual (n=21)group. The two groups showed no difference in any measurements at baseline.The implementation intentions group received implementation intentions training as well as regular medication treatment. The 10-session intervention program was conducted twice a week, and the participants attended the 1.5-hour session in groups of 6一8 participants. The patients were instructed to flexibly apply the combination of verbal and imagery encoding strategy in daily life. The current implementation intentions program consisted of 5 modules:l)psycho-education introduction of prospective memory and the prospective memory difficulties in daily life; 2) training the verbal component; 3) training the visual imagery component; 4) simulated application of implementation intentions; 5) generalized exercises in daily life.Treatment as usual group mainly received regular medication treatment. The two groups received a series of measures on prospective memory, medication management,social function, neurocognition, and psychological state at baseline, post-treatment and 3-month follow-up. Prospective memory was assessed by computer-based prospective memory task, adapted Memory for Intentions Screening Test (MIST),phone call task, Prospective and Retrospective Memory Questionnaire (PRMQ).Medication management was measured by Medication Management Ability Assessment (MMAA). Social function was measured by Beijing Performance-based Functional Ecological Test (BJ-PERFECT), Personal and Social Performance scale (PSP) and Schizophrenia Quality of Life Scale (SQLS). Cognition was assessed by Sustained Attention to Response Task (SART), Chinese version of Letter-Number Span Test, logical memory and visual reproduction subscales of the Wechsler Memory Scale一Revised. Psychological state was measured by Satisfaction With Life Scale (SWLS), Beck Depression Inventory (BDI) and State-Trait Anxiety Inventory (STAI).
The results showed training一associated improvements on computer-based prospective memory and phone call task at post-treatment and 3-month follow-up assessments. In addition, implementation intentions training improved working ability subdomain and total score of BJ-PERFECT and logical memory delayed recall at post-treatment but elevated MIST performance at 3-month follow-up. The results also showed that less education, lower IQ, weaker cognition and psychosocial function predicted more improvements in prospective memory performance.
To summarize, our intervention program showed good effect and durability for prospective memory in schizophrenia patients. Besides, the program demonstrated short-term effects in social function and benefited more for patients with lower baseline functions. Thus, the low-cost, low-dropping rate training program has the potential to be widely used in community settings.