Deficits in cue detection and intention retrieval underlie prospective memory impairment in schizophrenia

Effects of bilateral repetitive transcranial magnetic stimulation on prospective memory in patients with schizophrenia: A double-blind randomized controlled clinical trial

AIMS

To investigate effects of repetitive transcranial magnetic stimulation (rTMS) on the prospective memory (PM) in patients with schizophrenia (SCZ).

METHODS

Fifty of 71 patients completed this double-blind placebo-controlled randomized trial and compared with 18 healthy controls' (HCs) PM outcomes. Bilateral 20 Hz rTMS to the dorsolateral prefrontal cortex at 90% RMT administered 5 weekdays for 4 weeks for a total of 20 treatments. The Positive and Negative Symptom Scale (PANSS), the Scale for the Assessment of Negative Symptoms (SANS), and PM test were assessed before and after treatment.

RESULTS

Both Event-based PM (EBPM) and Time-based PM (TBPM) scores at baseline were significantly lower in patients with SCZ than that in HCs. After rTMS treatments, the scores of EBPM in patients with SCZ was significantly improved and had no differences from that in HCs, while the scores of TBPM did not improved. The negative symptom scores on PANSS and the scores of almost all subscales and total scores of SANS were significantly improved in both groups.

CONCLUSIONS

Our findings indicated that bilateral high-frequency rTMS treatment can alleviate EBPM but not TBPM in patients with SCZ, as well as improve the negative symptoms.

SIGNIFICANCE

Our results provide one therapeutic option for PM in patients with SCZ.

The deficient cue monitoring and the facilitating effect of prosocial intention on prospective memory in patients with schizophrenia spectrum disorders

The study aimed to investigate the cognitive processing of prospective memory (PM) in patients with schizophrenia spectrum disorders (SSDs) by using an eye-tracking paradigm. In addition, the facilitating effects of prosocial intention (the desire to help others) on PM in SSDs were also examined. In phase 1, 26 patients (group1) and 25 healthy controls (HCs) were compared in an eye-tracking PM paradigm in terms of the PM accuracy and eye-tracking indices. In phase 2, 21 more patients (group2) were recruited, and a prosocial intention was introduced in the eye-tracking PM paradigm. Their PM accuracy and eye-tracking indices were compared with those in group1. The PM cue monitoring was indicated by the total fixation counts and fixation time on distractor words. In phase 1, group1 showed lower PM accuracy, fewer fixation counts and less fixation time on distractor words than HCs. In phase 2, group2 (with prosocial intention) performed significantly better than group1 (with typical instruction) on both PM accuracy and fixation time on distractor words. In both groups of SSDs, the PM accuracy was significantly correlated with both the fixation counts and the fixation time of distractor words. After controlling for the cue monitoring indices, the difference in PM accuracy remained significant between group1 and HCs but disappeared between group1 and group2. The cue monitoring deficit contributes to the PM impairment in SSDs. The facilitating effect of prosocial intention disappears after the control of cue monitoring, also indicating its critical role in PM.

The Chinese version of the Memory for Intentions Test (MIST): development and evaluation of its reliability and concurrent validity

This study aims to develop a simplified Chinese version of the "Memory for Intentions Test" (MIST), evaluate its reliability and concurrent validity, explore the inter-relationships among the MIST variables and the relationships between the MIST variables and socio-demographic factors.

Two hundred healthy, Chinese-speaking adults of the Han community participated in this study. Form A of the Chinese MIST and two prospective items of the Rivermead Behavioural Memory Test, Second Edition (RBMT-II, Chinese version) were administered to all participants to evaluate internal consistency, split-half reliability, and concurrent validity. Twenty of these participants were assessed twice on Form A with a two-week interval to examine test-retest reliability. They were also assessed on both Form A and Form B to examine alternate-form reliability.

The findings of the study indicated good internal consistency (Cronbach's α = .833) and excellent split-half reliability (r = .924-.930) among the six subscales of the Chinese MIST, although the internal consistency was low (Cronbach's α = .129) for individual PM trials. We also found adequate concurrent validity (ρ = .722, p< .001), test-retest reliability (ρ = .716, p < .001), and alternate-form reliability (ρ= .828, p < .001).

The Chinese MIST demonstrated suitable reliability and concurrent validity in the Chinese-speaking population. The present study provides a new standardized prospective memory test for the Chinese population, which would enhance future clinical research in this field on the Chinese mainland.

Prospective memory impairment in neurological disorders: implications and management

Prospective memory is a core neurocognitive ability that refers to memory for future intentions, such as remembering to take medications and to switch off appliances. Any breakdown in prospective memory, therefore, has serious implications for the ability to function independently in everyday life. In many neurological disorders, including Parkinson disease and dementia, prospective memory deficits are common even in the earliest stages and typically become more severe with disease progression. Consequently, clinical assessment of prospective memory is of critical importance. This article provides an overview of the various manifestations and neural bases of prospective memory deficits. To facilitate clinical decision-making, validated measures of this construct are identified and their suitability for clinical practice is discussed, focusing in particular on clinical sensitivity and psychometric properties. The article concludes by reviewing the approaches that can be used to rehabilitate different types of prospective memory impairment, and algorithms to guide the evaluation and treatment of these impairments are provided.

Instruments Measuring Prospective Memory: A Systematic and Meta-Analytic Review

OBJECTIVE

To identify the available measures to assess prospective memory (PM) abilities, to describe their content, and to quantitatively summarize the effects of various diseases on PM depending on the type of assessment.

METHOD

Three databases (PsycInfo, PsycArticles and PubMed) were searched up to June 2019 to identify the existing PM measures. The identified PM measures were classified according to the type of assessment: test batteries, single-trial procedures, questionnaires, and experimental procedures. The characteristics and psychometric properties were presented. PM performances were compared between patients with various diseases and controls depending on the type of assessment.

RESULTS

Most of the 16 measures identified evaluated both event- and time-based tasks, were linked to functional outcomes, showed empirical evidences regarding validity and reliability, and provided parallel versions. To a slightly lesser extent, few measures provided normative data, translations/adaptation into another language, cutoff scores for diagnostic purposes, qualitative scoring, parallel version, and external aids during the test. Compared to healthy controls, patients had significantly poorer performances when PM was assessed with experimental procedures. Heterogeneous data precluded the interpretation of a summary effect for test batteries, single-trial procedures, and questionnaires. Planned subgroup analyses indicated consistent PM impairment for patients compared to controls for three test batteries. However, PM complaints did not differ between patients and controls.

CONCLUSIONS

These results suggest that the use of PM test batteries and experimental procedures are relevant for detecting performance variations in diverse clinical populations. Clinical implications and directions for future research are discussed.

Comparing different tests to detect early manifestation of prospective memory decline in aging

Objective: Prospective memory (PM) is the ability to remember to perform future intentions. Previous studies have demonstrated that, compared to a younger cohort, healthy older adults have impairments in PM. Considering the importance of early detection of age-related PM decline, the present study aims to compare the performance of healthy older adults using three well-known PM tests commonly used in clinical settings.Method: In the present study, we tested 70 older adults (65-95 years old) using the Cambridge Prospective Memory Test (CAMPROMPT), the Memory for Intentions Screening Test (MIST) and the Royal Prince Alfred Prospective Memory Test (RPA-ProMem). In order to compare performance across tests and the interaction between age and cues, we performed a linear mixed model with random intercept and random slopes. Moreover, additional mixed models with random intercept were run for analyzing the additional information provided by MIST and RPA-ProMem regarding delay responses, response modality effects and type of errors committed.Results: Our data showed a drop in PM performance as age increased detected by all three tests. Furthermore, CAMPROMPT was the most sensitive test to identify differences in PM for event-and time-based cues, at least for participants with 65-77 years old. When data were analyzed in term of delay responses, participants were more accurate for 2 min delay (MIST) and 30 in delay (RPA-ProMem). Participants were less accurate when response modality was "verbal" compared to "action" (MIST) and made more PM errors as age increased.Conclusions: Overall, the study provides important information regarding age-related PM decline and can help researchers as well as clinicians in deciding the preferred test to evaluate PM performance.

The effect of implementation intentions on prospective memory performance in patients with schizophrenia: A multinomial modeling approach

Patients with schizophrenia (SCZ) consistently show prospective memory (PM) impairments, and the technique of implementation intentions has been shown to improve PM performance in these patients. PM is considered to have prospective and retrospective components. However, it remains unclear which component of PM is impaired in patients with SCZ and which component(s) is facilitated by implementation intentions (II). The present study aimed to examine these two issues. Forty-two patients with SCZ and 42 matched healthy controls were randomly assigned to an II group or a typical instruction group. All participants were administered a color-matching PM task. Results showed that, using a multinomial-modeling approach, patients with SCZ exhibited impairment in the retrospective component of PM. In addition, while II improved the prospective PM component in healthy controls, both prospective and retrospective PM components in patients with SCZ were improved. Together, our results shed light on the mechanism of PM impairment in SCZ patients and the mechanism of II in improving PM performance.

Prospective memory in schizophrenia: A meta-analysis of comparative studies

BACKGROUND

Impairment of prospective memory (PM) in schizophrenia has gained increasing attention. This meta-analysis systematically examined PM impairment in schizophrenia.

METHODS

Both English (PubMed, PsycINFO, EMBASE, and Cochrane Library) and Chinese (WanFang, Chinese Biomedical and China Journal Net databases) databases were systematically searched from their inception until August 14, 2017. Case-control studies of PM in schizophrenia were included. Standardized mean differences (SMDs) and their 95% confidence interval (CI) were calculated using the random-effects model.

RESULTS

Twenty-nine case-control studies (n = 2492) were included in the analyses. The overall and three subtypes of PM were compared between patients with schizophrenia (n = 1284) and healthy controls (n = 1208). Compared to healthy controls, patients performed significantly poorer in overall (SMD = -1.125), time-based (SMD = -1.155), event-based (SMD = -1.068), and activity-based PM (SMD = -0.563). Subgroup analyses revealed significant differences between older and younger patients (SMD = -1.398 vs. -0.763), higher male predominance and no sex predominance (SMD = -1.679 vs. -0.800), lower and higher education level (SMD = -1.373 vs.-0.637), chronic and first-episode patients (SMD = -1.237 vs. -0.641) and between eco-valid and dual-task laboratory measurements (SMD = -1.542 vs. -0.725) regarding overall PM. Meta-regression analysis showed that higher negative symptom score was significantly associated with more severe overall PM impairment in patients (P = 0.022).

CONCLUSIONS

In this meta-analysis the overall PM and all its subtypes, particularly the time-based PM, were significantly impaired in schizophrenia.

Effect of emotional cues on prospective memory performance in patients with schizophrenia and major depressive disorder

Prospective memory (PM) is the ability to remember to carry out future intentions when prompted by a cue, and previous studies have suggested that emotional PM cues may enhance PM performance. This study examined the influence of emotional cues on PM performance in patients with schizophrenia and major depressive disorder. All participants were required to respond to emotional or neutral PM cues while completing a working memory task. Healthy participants showed improved PM performance with positive and negative cues. Patients with major depressive disorder were not impaired in PM performance and showed significant improvement in PM performance when cued by negative but not positive cues. Patients with schizophrenia had impaired PM performance irrespective of cue emotionality. In addition, the majority of patients with schizophrenia failed to show an emotional enhancement effect, and only those who had normal arousal ratings for negative PM cues showed emotional enhancement effect. These findings show for the first time that patients with schizophrenia exhibit PM impairments even with emotional cues, and suggest that arousal may be a critical factor for schizophrenia patients to utilize emotional cues to facilitate execution of future actions. In patients with major depressive disorder, our findings suggest that the negative bias in attention and retrospective memory may also extend to memory for future actions. These novel findings have both theoretical and clinical implications.

Development and reliability of the Prospective Memory Assessment for Children & Youth (PROMACY): A preliminary study in a nonclinical sample

Prospective memory (PM), "remembering to remember," has been linked to important functional outcomes in adults. Studies of PM in children and adolescents would benefit from the development and validation of developmentally appropriate clinical measures with known psychometric properties. The Prospective Memory Assessment for Children & Youth (PROMACY), a performance-based measure of PM, was developed for the Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol, Memory and Executive Functioning Substudy, and includes Summary, Time-, and Event-based scores derived from eight trials with an ongoing word search task. Fifty-four healthy perinatally HIV-exposed, uninfected children and youth, mean age 13 years, 54% female, 76% Black/non-Hispanic, and 61% impoverished were included in this psychometric analysis. PROMACY Summary Scores demonstrated low, but broadly acceptable internal consistency as measured by Cronbach's alpha and Spearman-Brown. Better PROMACY performance was associated with older age, but no other demographic factors. Generally medium-sized correlations were observed between the PROMACY Summary Score and standard clinical measures of retrospective memory, working memory, executive functions, and IQ. Findings from this preliminary psychometric study of nonclinical children and youth provide cautious support for the internal consistency and construct validity of PROMACY's Summary Score that awaits replication and extension in larger samples of healthy children, youth and clinical populations.

Prospective memory in obsessive compulsive disorder

Studies on the nature and extent of prospective memory impairment in patients with obsessive-compulsive disorder are relatively scarce. The present study examined prospective memory in patients with obsessive-compulsive disorder in comparison to patients with schizophrenia and healthy controls. Prospective memory was assessed using Memory for Intentions Screening Test (MIST). Further, the participants were administered Delis-Kaplan Executive Function System Tower Test, Wisconsin Card Sorting Test, and Stroop Test for assessing their planning ability, mental flexibility and cognitive inhibition, respectively. Monitoring was assessed by frequency of clock checking. Results indicated that as compared to healthy controls, the patients with obsessive-compulsive disorder performed poorly on both time- and event-based prospective memory tasks, whereas, patients with schizophrenia performed poorly on time-based prospective memory task only. Further, both the patient groups had comparable performance across time- and event-based tasks. Results of error analysis indicated that patients with obsessive-compulsive disorder mainly committed no response and task substitution errors, whereas patients with schizophrenia committed no response errors. Except monitoring, none of the neurocognitive variables correlated with time or event-based prospective memory in any group. The findings are discussed in the light of their implications for retraining of prospective memory deficits in patients with obsessive-compulsive disorder and schizophrenia.

Prospective Memory Performance in Persons With Schizophrenia and Bipolar Disorder and Healthy Persons

PURPOSE

There is a paucity of studies comparing prospective memory (PM) impairment between persons with schizophrenia and bipolar disorder. The aim of this study was to directly compare PM performances of these two groups and healthy controls.

DESIGN AND METHODS

A total of 44 persons with schizophrenia and 76 with bipolar disorder, and 44 healthy controls formed the study sample.

FINDINGS

Patients were found to be impaired in PM relative to controls and the two patient groups showed similar level of PM performance after controlling confounding sociodemographic and clinical variables.

PRACTICE IMPLICATIONS

The findings add to the evidence concerning the neurocognitive similarity between cohorts of schizophrenia and bipolar disorder with respect to PM. Rehabilitative effort in PM remedies for both patient groups is warranted.

A CREB1 Gene Polymorphism (rs2253206) Is Associated with Prospective Memory in a Healthy Cohort

Prospective memory (PM) is generally defined as remembering to perform intended actions in the future and is important for functioning in daily life. Cyclic adenosine monophosphate (cAMP) responsive element binding protein 1 (CREB1) plays an important role in cognitive functions. In this study, we hypothesized that genetic variation in the CREB1 gene is associated with PM. We genotyped a CREB1 promoter polymorphism rs2253206 and tested it for association with PM in 619 healthy subjects. PM performance was measured using the Prospective and Retrospective Memory Questionnaire (PRMQ), the Comprehensive Assessment of Prospective Memory (CAPM), and the Memory for Intentions Screening Test (MIST). Generalized linear model analysis was conducted for each PM test independently using different inheritance models to identify any associations (p < 0.05). After multiple testing adjustments, a significant association was found between the rs2253206 genotype and PM performance for CAPM instrumental activities of daily living measure (p = 0.016). These results suggest that the rs2253206 polymorphism in the CREB1 gene locus is associated with PM in healthy individuals and contributes to knowledge on the genetics of this particular type of memory.

Adults with developmental dyslexia show selective impairments in time-based and self-initiated prospective memory: Self-report and clinical evidence

BACKGROUND

Prospective memory (PM; memory for delayed intentions) would seem to be impaired in dyslexia but evidence is currently limited in scope.

AIMS

There is a need, therefore, firstly, to explore PM under controlled conditions using a broader range of PM tasks than used previously and, secondly, to determine whether objectively measured and self-reported PM problems can be found in the same individuals with dyslexia.

METHODS AND PROCEDURES

The responses of 30 adults with dyslexia were compared with those of 30 IQ-matched adults without dyslexia on a self-report and a clinical measure of PM.

OUTCOMES AND RESULTS

Dyslexia-related deficits were shown on the clinical measure overall and, more particularly, when PM responses had to be made to cues based on time rather than environmental events. Adults with dyslexia were also more likely to forget to carry out an intention under naturalistic conditions 24h later. On the self-report questionnaire, the group with dyslexia reported significantly more frequent problems with PM overall, despite using more techniques to aid their memory. In particular, problems were identified with longer-term PM tasks and PM which had to be self-initiated.

CONCLUSIONS AND IMPLICATIONS

Dyslexia-related PM deficits were found under both laboratory and everyday conditions in the same participants; the first time that this has been demonstrated. These findings support previous experimental research which has highlighted dyslexia-related deficits in PM when the enacting of intentions is based on time cues and/or has to be self-initiated rather than being in prompted by environmental events.

Impaired cue identification and intention retrieval underlie prospective memory deficits in patients with first-episode schizophrenia

OBJECTIVE

Schizophrenia is associated with impairment in prospective memory, the ability to remember to carry out an intended action in the future. It has been established that cue identification (detection of the cue event signaling that an intended action should be performed) and intention retrieval (retrieval of an intention from long-term memory following the recognition of a prospective cue) are two important processes underlying prospective memory. The purpose of this study was to examine prospective memory deficit and underlying cognitive processes in patients with first-episode schizophrenia.

METHODS

This study examined cue identification and intention retrieval components of event-based prospective memory using a dual-task paradigm in 30 patients with first-episode schizophrenia and 30 healthy controls. All participants were also administered a set of tests assessing working memory and retrospective memory.

RESULTS

Both cue identification and intention retrieval were impaired in patients with first-episode schizophrenia compared with healthy controls ( ps < 0.05), with a large effect size for cue identification (Cohen's d = 0.98) and a medium effect size for intention retrieval (Cohen's d = 0.62). After controlling for working memory and retrospective memory, the difference in cue identification between patients and healthy controls remained significant. However, the difference in intention retrieval between the two groups was no longer significant. In addition, there was a significant inverse relationship between cue identification and negative symptoms ( r = -0.446, p = 0.013) in the patient group.

CONCLUSION

These findings suggest that both cue identification and intention retrieval in event-based prospective memory are impaired in patients with first-episode schizophrenia. Cue identification and intention retrieval could be potentially used as biomarkers for early detection and treatment prognosis of schizophrenia. In addition, addressing cue identification deficit through cognitive enhancement training may potentially improve negative symptoms as well.

Longitudinal changes in prospective memory and their clinical correlates at 1-year follow-up in first-episode schizophrenia

This study aimed to investigate prospective memory (PM) and the association with clinical factors at 1-year follow-up in first-episode schizophrenia (FES). Thirty-two FES patients recruited from a university-affiliated psychiatric hospital in Beijing and 17 healthy community controls (HCs) were included. Time- and event-based PM (TBPM and EBPM) performances were measured with the Chinese version of the Cambridge Prospective Memory Test (C-CAMPROMPT) at baseline and at one-year follow-up. A number of other neurocognitive tests were also administered. Remission was determined at the endpoint according to the PANSS score ≤ 3 for selected items. Repeated measures analysis of variance revealed a significant interaction between time (baseline vs. endpoint) and group (FES vs. HCs) for EBPM (F(1, 44) = 8.8, p = 0.005) and for all neurocognitive components. Paired samples t-tests showed significant improvement in EBPM in FES (13.1±3.7 vs. 10.3±4.8; t = 3.065, p = 0.004), compared to HCs (15.7±3.6 vs. 16.5±2.3; t = -1.248, p = 0.230). A remission rate of 59.4% was found in the FES group. Analysis of covariance revealed that remitters performed significantly better on EBPM (14.9±2.6 vs. 10.4±3.6; F(1, 25) = 12.2, p = 0.002) than non-remitters at study endpoint. The association between EBPM and 12-month clinical improvement in FES suggests that EBPM may be a potential neurocognitive marker for the effectiveness of standard pharmacotherapy. Furthermore, the findings also imply that PM may not be strictly a trait-related endophenotype as indicated in previous studies.

The effect and mechanisms of implementation intention in improving prospective memory performance in schizophrenia patients

People with schizophrenia (SCZ) have been shown to have prospective memory (PM) deficits. PM refers to the ability to remember to perform delayed intentions in the future and plays an important role in everyday independent functioning in SCZ. To date, few studies have investigated methods to improve PM in SCZ. This study aimed to examine whether implementation intention can improve PM performance and to explore its underlying mechanisms. Fifty people with SCZ and 50 demographically matched healthy controls (HC) participated in this study. Participants were randomly assigned to an implementation intention condition or a control instruction condition. Participants were required to make PM responses when PM cue words appeared while they were undertaking an ongoing task with two levels of cognitive load (1-back or 2-back). Results showed that people with SCZ were impaired in PM, and implementation intention improved PM performances for both SCZ and HC. Implementation intention improved PM performance in SCZ in both the low and the high cognitive load conditions without ongoing task cost, suggesting that implementation intention improved PM remembering in an automatic way. These results indicate that implementation intention may be a beneficial technique for improving PM performances in people with SCZ.

Preserved Intention Maintenance and Impaired Execution of Prospective Memory Responses in Schizophrenia: Evidence from an Event-based Prospective Memory Study

Executive system dysfunction and impaired prospective memory (PM) are widely documented in schizophrenia. However, it is not yet clarified which components of PM function are impaired in this disorder. Two plausible target components are the maintenance of delayed intentions and the execution of PM responses. Furthermore, it is debated whether the impaired performance on frequently used executive tasks is associated with deficit in PM functions. The aim of our study was twofold. First, we aimed to investigate the specific processes involved in event-based PM function, mainly focusing on difference between maintenance of intention and execution of PM responses. Second, we aimed to unfold the possible connections between executive functions, clinical symptoms, and PM performance. An event-based PM paradigm was applied with three main conditions: baseline (with no expectation of PM stimuli, and without PM stimuli), expectation condition (participants were told that PM stimuli might occur, though none actually did), and execution condition (participants were told that PM stimuli might occur, and PM stimuli did occur). This procedure allowed us to separately investigate performances associated with intention maintenance and execution of PM responses. We assessed working memory and set-shifting executive functions by memory span tasks and by the Wisconsin Card Sorting Test (WCST), respectively. Twenty patients diagnosed with schizophrenia and 20 healthy control subjects (matched according to age and education) took part in the study. It was hypothesized that patients would manifest different levels of performance in the expectation and execution conditions of the PM task. Our results confirmed that the difference between baseline performance and performance in the execution condition (execution cost) was significantly larger for participants diagnosed with schizophrenia in comparison with matched healthy control group. However, this difference was not observed in the expectation condition. The PM performance in the execution condition was correlated with impaired executive functions in schizophrenia. Specifically, the size of execution cost positively correlated with percent of perseverative errors committed on WCST by the patient group. Our results suggest that maintenance of delayed intentions is unimpaired in schizophrenia, whereas the impairment in execution of PM responses is associated with set-shifting deficit.

Time-based but not event-based prospective memory remains impaired one year after the onset of schizophrenia: A prospective study

BACKGROUND

Prospective memory (PM) deficits have been consistently found in people with schizophrenia. Although there is evidence to suggest that PM deficits may be putative markers for schizophrenia, no longitudinal study has investigated the persistence of PM deficits.

AIMS

We examined whether PM deficits persist after the onset of schizophrenia, and compared the trajectories of time- and event-based PM performance 12 months after illness onset. We also examined whether the association between PM and clinical symptoms changes over time 12 months after illness onset.

METHOD

We recruited 58 individuals with first-episode schizophrenia for a 12-month follow-up study. Comparison participants were 37 healthy individuals who were matched in terms of demographics and intelligence with the patient group. PM functions and clinical symptoms were measured at baseline, the sixth month, and the twelfth month, using a computerized PM task and the Positive and Negative Syndrome Scale.

RESULTS

People with schizophrenia showed a gradual improvement in both time- and event-based PM 12 months after illness onset. However, compared to event-based PM, deficit in time-based PM persisted and was relatively stable. At baseline, PM functions were not associated with clinical symptoms. However, an association between time-based PM and PANSS positive and general symptoms emerged 12 months after the onset of schizophrenia.

CONCLUSION

People with first-episode schizophrenia exhibit persistent time-based PM deficit. Our findings support that PM deficit, in particular, time-based deficit, may be a putative neuropsychological marker of schizophrenia.

Event-related brain potential correlates of prospective memory in symptomatically remitted male patients with schizophrenia

Prospective memory (PM) refers to the ability to remember to perform intended actions in the future. Although PM deficits are a prominent impairment in schizophrenia, little is still known about the nature of PM in symptomatically remitted patients with schizophrenia. To address this issue, event-related brain potentials (ERPs) were recorded from 20 symptomatically remitted patients with schizophrenia and 20 healthy controls during an event-based PM paradigm. Behavioral results showed that symptomatically remitted patients with schizophrenia performed poorly on the PM task compared with healthy controls. On the neural level, the N300, a component of the ERPs related to PM cue detection, was reliable across these two groups, suggesting a degree of functional recovery of processes supporting cue detection in patients with symptomatically remitted schizophrenia. By contrast, the amplitude of the prospective positivity, a component of the ERPs related to PM intention retrieval, was significantly attenuated in symptomatically remitted schizophrenia patients relative to healthy controls. Furthermore, a significant positive correlation between the amplitude of the prospective positivity and accuracy on the PM task was found in those patients, indicating that patients’ poor performance on this task may result from the failure to recover PM cue-induced intention from memory. These results provide evidence for the existence of altered PM processing in patients with symptomatically remitted schizophrenia, which is characterized by a selective deficit in retrospective component (intention retrieval) of PM. Therefore, these findings shed new light on the neurophysiological processes underlying PM in schizophrenia patients during clinical remission.

Self-predictions of prospective memory in HIV-associated neurocognitive disorders: evidence of a metamemory deficit

HIV-associated neurocognitive disorders (HAND) are associated with deficits in prospective memory (PM; "remembering to remember"), conferring risk of daily functioning declines. However, self-perceptions of PM functioning are not reliably associated with PM performance in HIV, suggesting a possible deficit in awareness of PM abilities (meta-PM). Our study examined meta-PM in HAND and its correlates using self-predictions of laboratory-based PM performance. Performance-based PM abilities, self-reported prediction of PM performance, and PM complaints in everyday life were assessed in 49 individuals with HAND, 93 HIV+ without HAND (HIV+ noHAND), and 121 seronegative adults (HIV-). After controlling for group-level differences, HAND was associated with a greater number of PM symptoms in everyday life and worse PM performance when compared with both HIV+ noHAND and HIV- samples. Although HAND individuals reported somewhat lower predictions regarding their laboratory PM performance relative to the other study groups, they nevertheless exhibited significantly greater inaccurate overconfidence in time-based PM abilities. Within the HAND group, overconfidence in time-based meta-PM was associated with executive dysfunction and antiretroviral (ARV) nonadherence. HAND individuals evidenced a moderate deficit in awareness of PM functioning characterized by overconfidence in time-based PM abilities. Overconfidence in PM may result in absence of compensatory strategy use, and lead to increased errors in daily functioning (e.g., ARV nonadherence).

Problems in remembering to carry out future actions in first-episode schizophrenia: primary or secondary impairment?

Prospective memory (PM) is the ability to remember to carry out intended actions in the future. Empirical evidence suggests that PM deficits exist in individuals with chronic schizophrenia. However, it is unclear whether PM deficits in first-episode schizophrenia exist independently from other neuropsychological deficits. Moreover, prior research using patients with first-episode has been limited to small inpatient samples. We aimed to clarify the nature and extent of PM deficits in individuals with first-episode schizophrenia, using a large outpatient sample. Participants were 91 clinically stable outpatients with first-episode schizophrenia and 83 healthy controls. PM was assessed using both a subjective self-reported checklist and a laboratory-based task capturing time- and event-based PM. A battery assessing verbal and visuo-spatial working memory, as well as executive functions was also administered. ANOVA analyses showed that patients with first-episode schizophrenia performed significantly poorer than healthy controls in time- and event-based PM. Stepwise linear regression analyses suggested that cognitive flexibility predicted time- and event-based PM; and working memory predicted event-based PM. Subgroup analyses showed that "cognitive-preserved" patients with first-episode schizophrenia tended to perform poorer in time-based PM deficit than healthy controls who were matched in IQ and other neuropsychological functions. Overall, our results provide substantial evidence to support that time-based PM deficits in first-episode schizophrenia are apparent and not entirely attributable to other neuropsychological deficits. PM may constitute a neuropsychological marker for schizophrenia.

Prospective memory predicts the level of community living skills in schizophrenia

Schizophrenia patients are known to have prospective memory (PM) deficits. There is no robust evidence showing that PM deficits have a major impact on community living skills in schizophrenia. The aim of this study was to examine the association between PM and community living skills in schizophrenia. Forty-four individuals with schizophrenia formed the study sample. Participants׳ psychopathology, prospective and retrospective memory, level of intelligence, and community living skills were measured with standardized instruments. In bivariate analyses, community living skills overall but not self-care correlated with PM total and subscales scores. In multivariate analyses, event-based PM was more predictive than time-based PM of the level of community living skills. In conclusion, PM has a significant impact on community living skills in schizophrenia and attention should be paid to this type of memory disturbance in rehabilitation of schizophrenia.

Prospective memory in schizophrenia: a review

The wide range of psychological and cognitive symptoms associated with schizophrenia can often affect the level of independence that individuals with schizophrenia can achieve in their lives. Prospective memory (PM), or memory associated with future intentions, has been proposed as a useful indicator of select independent living skills. Currently, there is limited research with regards to prospective memory in schizophrenia. The current review systematically summarizes the literature focusing on prospective memory in schizophrenia and concludes that individuals with schizophrenia exhibited both an impairment in PM when compared to healthy controls and a general lack of awareness regarding these deficits. The existing research also suggests that PM deficits are not related to chronicity of illness or medications associated with schizophrenia. Limited findings suggest that PM deficits in individuals with schizophrenia may be associated with the ability to live independently and instrumental activities of daily living.

Construct validity of the Memory for Intentions Screening Test (MIST) in healthy older adults

The Memory for Intentions Screening Test (MIST) is a clinical measure of prospective memory. There is emerging support for the sensitivity and ecological relevance of the MIST in clinical populations. In the present study, the construct validity of the MIST was evaluated in 40 younger (18-30 years), 24 young-old (60-69 years), and 37 old-old (70+ years) healthy adults. Consistent with expectations derived from the prospective memory and aging literature, older adults demonstrated lower scores on the MIST's primary scale scores (particularly on the time-based scale), but slightly better performance on the seminaturalistic 24-hour trial. Among the healthy older adults, the MIST showed evidence of both convergent (e.g., verbal fluency) and divergent (e.g., visuoperception) correlations with standard clinical tests, although the magnitude of those correlations were comparable across the time- and event-based scales. Together, these results support the discriminant and convergent validity of the MIST as a measure of prospective memory in healthy older adults.

Assessment of prospective memory in schizophrenia using the Chinese version of the Cambridge Prospective Memory Test: a controlled study

INTRODUCTION

Data on the psychometric assessment of prospective memory (PM) are limited. The Cambridge Prospective Memory Test (CAMPROMPT) and its Chinese version (CAMPROMPT-C) have been applied to a variety of clinical conditions except for chronic schizophrenia. This controlled study explored the clinical utility of the CAMPROMPT-C in patients with schizophrenia by comparing their PM performance with that of normal controls.

METHODS

Forty-four schizophrenia patients and 44 normal controls formed the study sample. Sociodemographic characteristics, PM, retrospective memory, and intelligence were measured in all subjects. Patients' psychopathology was rated with a standardized instrument.

RESULTS

Patients performed worse than normal controls on both the sum and subscale scores of the CAMPROMPT-C. Patients had comparable performances in PM subtypes. Bivariate analyses revealed that education level, intelligence, and retrospective memory were associated with PM functions.

DISCUSSION

The study supports the clinical utility of the CAMPROMPT-C in chronic schizophrenia and corroborated the significant relationship between PM and education, intelligence, and retrospective memory.

Prospective memory impairments in schizophrenic patients

OBJECTIVE

Memory impairment is one of the most pervasive cognitive dysfunctions in schizophrenic patients. The aim of the current study was to conduct the most comprehensive assessment of how prospective memory (PM) is affected in schizophrenia in comparison with healthy controls.

METHODS

In this study, 30 first-episode schizophrenic patients who fulfilled the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders based on the diagnostic interview were recruited from eight regional psychiatric clinics in Iran. All participants were males (age 27-42). Moreover, 28 healthy controls were recruited from the same social-class as the patients. The Prospective and Retrospective Memory Questionnaire (PRMQ), PM tasks, and the Virtual Week Board Game were administered. Moreover, clinical symptoms were rated using the positive and negative symptoms scale.

RESULTS

The results showed that in all of the memory types, the group with dominant positive symptoms was superior to the group with dominant negative symptoms. In addition, the results showed that in all of the memory types, the control group had superiority to the schizophrenic group. The most considerable differences between groups were in time-based PM tasks, irregular event-based virtual week tasks, and retrospective tasks (PRMQ).

CONCLUSION

The current study confirmed that schizophrenic patients have severe PM deficits.

Prospective memory in schizophrenia: relationship to medication management skills, neurocognition, and symptoms in individuals with schizophrenia

OBJECTIVE

Impaired adherence to medication regimens is a serious concern for individuals with schizophrenia linked to relapse and poorer outcomes. One possible reason for poor adherence to medication is poor ability to remember future intentions, labeled prospective memory skills. It has been demonstrated in several studies that individuals with schizophrenia have impairments in prospective memory that are linked to everyday life skills. However, there have been no studies, to our knowledge, examining the relationship of a clinical measure of prospective memory to medication management skills, a key element of successful adherence.

METHODS

In this Study 41 individuals with schizophrenia and 25 healthy adults were administered a standardized test battery that included measures of prospective memory, medication management skills, neurocognition, and symptoms.

RESULTS

Individuals with schizophrenia demonstrated impairments in prospective memory (both time and event-based) relative to healthy controls. Performance on the test of prospective memory was correlated with the standardized measure of medication management in individuals with schizophrenia. Moreover, the test of prospective memory predicted skills in medication adherence even after measures of neurocognition were accounted for.

CONCLUSIONS

This suggests that prospective memory may play a key role in medication management skills and thus should be a target of cognitive remediation programs.

Prospective memory deficits in euthymic bipolar disorder patients: a preliminary study

INTRODUCTION

Prospective memory refers to the ability to remember to do something in the future. To date, little is known about prospective memory deficits in bipolar disorder (BD) in remission (euthymia). This study examined the nature and correlates of prospective memory in these patients.

METHODS

Forty-seven euthymic BD patients and 47 matched healthy controls formed the study sample. Socio-demographic and basic clinical characteristics, prospective memory (Cambridge Prospective Memory Test [CAMPROMPT]), retrospective memory (immediate Logical Memory subtests of the Wechsler Memory Scales-Revised [WMS-R]), IQ (Raven's Progressive Matrices) and executive functioning (Wisconsin Card Sorting Test) were measured in all participants; patients' symptoms were rated with the 17-item Hamilton Depression Rating Scale and the 11-item Young Mania Rating Scale.

RESULTS

Patients performed significantly worse on time-based prospective memory compared to controls. Multivariate analyses revealed that patients' lower score on Raven's Progressive Matrices significantly contributed to poor performance on time-based prospective memory, whereas lower scores on WMS-R Logical Memory subtest contributed to poor performance on event-based prospective memory; in controls, lower education level and older age significantly contributed to poor performance on time-based and event-based prospective memory, respectively.

DISCUSSION

Prospective memory deficits persist in remitted BD patients suggesting that prospective memory impairment constitutes a trait deficit in BD.

Prospective memory performance in patients with drug-naïve, first-episode psychosis

Schizophrenia is associated with an impairment of prospective memory (PM) which refers to the ability to remember to carry out an intended action in the future. However, most of these studies were limited to chronic samples. The current study examined the event-based PM and time-based PM using a dual-task paradigm in 22 drug-naïve, first-episode psychosis (FEP) patients and 23 healthy controls. Results indicated that FEP patients performed significantly poorer than healthy controls in both event-based and time-based PM. However, the significant difference in time-based PM disappeared after controlling for working memory. Correlation analysis indicated that both types of PM did not correlate with positive symptoms or negative symptoms, duration of illness, or duration of untreated psychosis. However, time-based PM was correlated with the general psychopathology subscale of the PANSS. Taken together, these findings suggest that PM deficits are present in drug-naïve FEP patients; impairment of event-based PM appears to occur independently, whereas time-based PM impairment may be, in part, a secondary consequence of a working memory deficit.

Preparatory distributed cortical synchronization determines execution of some, but not all, future intentions

Associating intentions to events that cue future behaviors is a central aspect of human cognition. There is limited understanding of the neural dynamics supporting recognition of intention-related events, with little known about how pre-event brain state varies as a function of intention specificity. Prior to recognized events (that cued planned behavior) occurring during an unrelated activity, we found increased steady-state visual evoked potential (ssVEP) and intrinsic gamma synchronization for ill- compared to well-specified events, as measured by EEG. Enhanced fronto-temporo-parietal ssVEP synchrony emerged preceding ill compared to well-specified events, and the degree of synchrony predicted the completion of ill-specified intentions but predicted failure to complete well-specified intentions. Distinct executive processing and neural states are therefore optimal for anticipating and fulfilling future intentions varying in event specificity.

Prospective memory in schizophrenia and schizotypy

INTRODUCTION

Most evidence suggests that schizophrenia is associated with pervasive prospective memory (PM) impairment that does not vary as a function of task demands. However, a central tenet of the Multiprocess Framework is that PM involves both automatic and strategic processes, and that their relative prominence varies as a function of PM task characteristics, such as target-cue saliency.

METHODS

Participants with schizophrenia (n = 30), matched controls (n = 29), low schizotypes (n = 35), and high schizotypes (n = 36) were administered a PM measure in which saliency was manipulated. To further clarify the relationship between PM and schizotypy, high and low schizotypies were additionally assessed on Virtual Week, a laboratory measure which has documented sensitivity to schizophrenia-related impairment.

RESULTS

Relative to controls, participants with schizophrenia exhibited PM difficulties, but the magnitude of this deficit did not vary as a function of target-cue saliency. High and low schizotypes did not differ on any PM test parameter.

CONCLUSIONS

These data are consistent with other evidence showing that schizophrenia is characterised by generalised PM impairment. However, the absence of any schizotypy effects on PM does not support the recent suggestion that PM may represent an endophenotype for schizophrenia.

Characteristics and clinical correlates of prospective memory performance in first-episode schizophrenia

OBJECTIVE

The aim of this study was to examine prospective memory (PM) and its socio-demographic, clinical, and neurocognitive correlates in first episode schizophrenia (FES).

METHODS

Fifty-one FES patients and 42 healthy controls formed the study sample. Time- and event-based PM (TBPM and EBPM) performance were measured with the Chinese version of the Cambridge Prospective Memory Test (C-CAMPROMPT). A battery of neuropsychological tests was also administered. Patients' clinical symptoms were evaluated with the Positive and Negative Symptom Scale (PANSS).

RESULTS

Patients performed significantly worse in both TBPM (8.7 ± 5.3 vs. 14.8 ± 3.5) and EBPM (11.3 ± 4.7 vs. 15.7 ± 2.7) than the controls. After controlling for age, gender, education level and neurocognitive test score, the difference in performance on the two types of PM tasks between patients and controls was no longer present. In multiple linear regression analyses, longer duration of untreated psychosis (DUP), lower scores of the Hopkins Verbal Learning Test-Revised (HVLT-R) and the categories completed of the Wisconsin Card Sorting Test (WCST-CC) and higher score of the Color Trails Test-2 (CTT-2) contributed to poorer TBPM performance, while lower score of HVLT-R, higher score of the perseverative errors of the Wisconsin Card Sorting Test (WCST-PE) and longer DUP contributed to worse performance on EBPM.

CONCLUSIONS

Both subtypes of PM are impaired in first-episode schizophrenia suggesting that PM deficits are an integral part of the cognitive dysfunction in the disease process.

A Review of Virtual Week for Prospective Memory Assessment: Clinical Implications

It is now recognised that prospective memory (PM) failures are commonly observed in clinical groups, and have important implications for functional independence. However, well-validated measures of PM have traditionally been lacking, making this construct difficult to assess in clinical practice. Rendell and Craik's (2000) Virtual Week measure was developed as an indicator of PM, and has been shown to have good psychometric properties and be sensitive to the effects of normal and abnormal adult ageing, as well as various forms of pathology. In this article, an overview of Virtual Week's characteristics is presented, and the literature relating to use of this measure in various populations reviewed. The potential implications of the development of a new computerised version of Virtual Week for clinical practice are discussed.

Memory for Intentions Screening Test: Psychometric Properties and Clinical Evidence

As the field of prospective memory (ProM) research has expanded, recognition of the need to make a clinical diagnosis of ProM difficulties has also increased. In addition, there is increasing interest in understanding in more detail the ways in which ProM deficits differ in populations with different underlying neurological dysfunctions. While questionnaires, naturalistic studies and laboratory studies have all been invaluable in furthering our understanding of ProM, until recently there has not been a standardised clinical measure. The Memory for Intentions Screening Test (MIST) was designed to be a relatively brief clinical measure of ProM in clinical populations. The MIST allows for comparisons of performance with event-based and time-based cues. The MIST also has some items with a short (2-minute) and some with a long (15-minute) delay period. Finally, the MIST contains items that require a verbal response as well as items that require an action response. The MIST has now been used in studies of normal ageing as well as a range of clinical populations, including individuals with traumatic brain injury, individuals with HIV infection and individuals with schizophrenia. The psychometric properties of the MIST have been found to be acceptable. Data from each of the clinical populations that have been administered the MIST demonstrate good specificity and sensitivity of the measure as well as the ability to begin to make comparisons about different patterns of performance between disease types.

The role of prospective memory in medication adherence: a review of an emerging literature

Although neurocognitive impairment is an established risk factor for medication nonadherence, standard neurocognitive tests developed for clinical purposes may not fully capture the complexities of non-adherence behavior or effectively inform theory-driven interventions. Prospective memory, an innovative cognitive construct describing one's ability to remember to do something at a later time, is an understudied factor in the detection and remediation of medication non-adherence. This review orients researchers to the construct of prospective memory, summarizes empirical evidence for prospective memory as a risk factor for non-adherence, discusses the relative merits of current measurement techniques, and highlights potential prospective memory-focused intervention strategies. A comprehensive literature review was conducted of published empirical studies investigating prospective memory and medication adherence. Overall, reviewed studies suggest that prospective memory is an important component of medication adherence, providing incremental ecological validity over established predictors. Findings indicate that prospective memory-based interventions might be an effective means of improving adherence.

Prospective memory in non-psychotic first-degree relatives of patients with schizophrenia

Although a number of studies have found prospective memory (PM) impairment in patients with schizophrenia, very little is known about the PM performance in non-psychotic relatives of these patients. The current study aimed to explore the PM performance in non-psychotic first-degree relatives of these patients. Two groups of participants (26 non-psychotic first-degree relatives of schizophrenia patients and 26 healthy comparison participants) were administered three PM tasks (time-, event-, and activity-based) and a set of neurocognitive tests. Results showed that the relatives performed significantly worse than the comparisons on most indices of the PM tasks, with a similar pattern of impairment found in other neurocognitive measures. Together with findings from previous studies, results of the current study suggest that PM may be a potential endophenotype for schizophrenia.

Independent association of prospective memory with retrospective memory and intelligence in schizophrenia: a controlled study

Prospective memory (PM) refers to the ability to remember to do something in the future. This study examined the relationship between three PM subtypes, and intelligence and retrospective memory (RM) in schizophrenia patients and healthy controls. The study sample comprised 110 schizophrenia patients and 110 healthy controls matched according to age, sex, and level of education. The patients' clinical condition was evaluated with the Brief Psychiatric Rating Scale. Time-, event-, and activity-based PM and RM (immediate and delayed Logical Memory subtests of the Wechsler Memory Scales-Revised), executive functioning (Design Fluency Test, Tower of London-4 disk, and Wisconsin Card Sorting Test), and intelligence (Raven's Progressive Matrices) tests were administered to all participants. Correlation analyses showed time- and event-based PM to be significantly associated with RM in both the patients and controls, but with intelligence only in the patients. After controlling for covariates, only time-based PM was associated with RM in the controls and only event-based PM with intelligence in the patients. In schizophrenia, PM deficit may arise from the impairments of the retrospective components of memory.

Prospective memory deficits in patients with bipolar disorder: a preliminary study

Prospective memory (PM) is the ability to remember to do something in the future without explicit prompts. To date, little has been known about PM deficits in bipolar disorder (BD). This study examined the nature and correlates of PM in patients with BD. Forty clinically stable BD patients and 40 matched healthy controls formed the study sample. Socio-demographic characteristics, PM, psychosocial functioning, retrospective memory (RM), and IQ were measured in all participants, whereas clinical condition was measured in patients with standardized assessment instruments. Patients performed significantly more poorly on the time-based PM task than controls (10.6 ± 5.0 vs. 14.6 ± 3.0, p < .001). In correlation analyses, older age, lower education, more severe depressive and manic symptoms, poor psychosocial functioning, poor RM, and lower scores in IQ were significantly associated with poor performance in the time-based PM task, whereas poor RM and lower scores in IQ associated with poorer performance in the event-based PM task in patients. In multivariate analyses, severity of depression and older age significantly contributed to poor performance in the time-based PM task, whereas poor RM contributed to poor performance in the event-based PM task in patients. The time-based PM is impaired in BD patients. Depressive symptoms, age, and RM were determinants of certain aspects of impaired PM performance in BD patients.

Meta-analysis of prospective memory in schizophrenia: nature, extent, and correlates

Prospective memory (PM) is the ability to remember to carry out an intended action in the future and it is an important function for everyday living. Studies have found that the neural basis of PM is located mainly in the prefrontal lobes (particularly in Brodmann Area 10) and patients with schizophrenia have functional deficits in this area. The present study provided a meta-analytic review of PM performances in patients with schizophrenia in 11 studies. A total of 485 patients with schizophrenia and 409 controls were included. Results showed that patients with schizophrenia exhibited impairments in all time- (d=-1.33), event- (d=-0.827), and activity-based (d=-0.729) PM, with time-based PM more impaired than event-based PM. In addition, PM was found to be significantly correlated with negative symptoms (r=-0.18), general psychopathology (r=-0.168), medication dosage (r=-0.119), duration of illness (r=-0.131), age (r=-0.23), education (r=0.249), IQ (r=0.439) and premorbid IQ (r=0.356). It has theoretical and clinical implications. Theoretically, the results indicate time-based PM involves more initiation than event-based PM. Clinically, the results indicate patients on high dose of antipsychotic medication and with long duration of illness need special attention from care givers for PM problems.

Timing is everything: antiretroviral nonadherence is associated with impairment in time-based prospective memory

Nonadherence to combination antiretroviral (ARV) therapies (cART) is highly prevalent and significantly increases the risk of adverse human immunodeficiency virus (HIV) disease outcomes. The current study evaluated the hypothesis that prospective memory-a dissociable aspect of episodic memory describing the ability to execute a future intention-plays an important role in successful cART adherence. Seventy-nine individuals with HIV infection who were prescribed at least one ARV medication underwent a comprehensive neuropsychological and neuromedical evaluation prior to completing a 1-month observation of their cART adherence as measured by electronic medication monitoring. Nonadherent individuals (n = 31) demonstrated significantly poorer prospective memory functioning as compared to adherent persons (n = 48), particularly on an index of time-based ProM (i.e., elevated loss of time errors). Deficits in time-based prospective memory were independently predictive of cART nonadherence, even after considering the possible influence of established predictors of adherence, such as general cognitive impairment (e.g., retrospective learning and memory) and psychiatric comorbidity (e.g., depression). These findings extend a nascent literature showing that impairment in time-based prospective memory significantly increases the risk of medication nonadherence and therefore may guide the development of novel strategies for intervention. (JINS, 2009, 15, 42-52.).

Psychometric characteristics of the memory for intentions screening test

The construct of prospective memory (ProM), or "remembering to remember," is hypothesized to play a critical role in normal activities of daily living and has increasingly been the focus of clinical research over the past 10 years. However, the assessment of ProM as part of routine clinical care is presently hampered by the paucity of psychometrically sound, validated ProM tests available in the neuropsychological literature. The Memory for Intentions Screening Test (MIST; Raskin, 2004) is a user-friendly, comprehensive measure of ProM that demonstrates preliminary evidence of construct validity. Extending this research, this study evaluated the psychometric characteristics of the MIST in a sample of 67 healthy adults. Despite a mildly restricted range of scores, results revealed excellent inter-rater reliability, adequate split-half reliability, and satisfactory inter-relationships between the MIST summary score, subscales, and error types. Analysis of demographic correlates showed that the MIST was independently associated with both age and education, but not with sex or ethnicity. These findings broadly support the psychometric properties of the MIST, specifically its reliability and expected relationships with demographic characteristics. Recommendations are provided regarding future research to enhance the clinical usefulness of the MIST.

Prospective memory deficits in subjects with schizophrenia spectrum disorders: a comparison study with schizophrenic subjects, psychometrically defined schizotypal subjects, and healthy controls

Memory impairment is one of the core deficits in schizophrenia. This study explored the memory profiles of schizophrenic and psychometrically defined schizotypal subjects. The study participants included 15 patients with schizophrenia, 41 schizotypal subjects, and 20 healthy controls. All of the participants completed verbal and visual memory, working memory, and prospective memory tasks. The results showed that patients with schizophrenia were impaired in all aspects of memory function, whereas the schizotypal subjects tended to show moderate to large impairment effect sizes in prospective memory. It is suggested that prospective memory be considered a potential endophenotype of schizophrenia.