Long term memory impairment in schizophrenia: investigating the deficit and its remediation using mnemonics

Schizophrenia patients have difficulty with learning new information and organizing this into meaningful categories, or at least accessing the systems available for use of these effective strategies. Our initial research compared ‘healthy’ controls (n=23) matched to individuals with schizophrenia (n=23) on memory tasks using verbal and non-verbal material. The study used a quantitative mixed matched pairs design, with between participants’ factors comparing schizophrenia patients and controls memory for words and faces across directed or nil directed groups, and within subjects factors comparing memory performance at different time points. The study aimed to establish the conditions for improving memory performance in the short-term and after a one-week delay. Matched-pairs were randomly allocated to remember (n=13) or mnemonic conditions (n=10). Improved encoding was facilitated by training the application of mnemonic strategies to highly structured lists. We demonstrate significant effects of both group, and instruction, which interacted with stimulus type, indicating poorer performance for faces than words. We demonstrate that mnemonic-trained individuals with chronic schizophrenia performed at the same level as untrained control participants .In the final session, a significant overall advantage for mnemonic instructions was maintained. A “memory-for-foils” method revealed a remaining deficit in retrieval processing, underlining the need for strategies to improve encoding but also retrieval. Our second experiment was a preliminary exploration of the effectiveness of mnemonic training via a web-based package. We investigate whether a ‘drill-and-practice’ program training in mnemonic strategies would facilitate generalized use and benefit everyday functioning. The experiment compared the effects of two (‘mnemonic’ versus ‘remember’) online computerized remediation training programs similar to that of the first study, in 40 individuals with chronic schizophrenia. We found mnemonic training delivered via a web-based intervention to be ineffective due to motivational difficulties, with no significant effects between groups on mnemonic versus remember training. The only effect replicated in the memory-testing sessions was much better performance with word than face cues. We discuss future directions for developing effective interventions making use of the potentially powerful benefits of mnemonics to remediate memory dysfunction in chronic schizophrenia.