Cannabis-related deficits in real-world memory

Immersive virtual plus-maze to examine behavior and psychophysiological-related variables in young people with problematic alcohol and cannabis consumption

Stressful events appear to be risky situations that can precipitate the consumption of drugs. One way to recreate stressful contexts, in an ecological and controlled method, is through immersive virtual reality (VR). In our study, we designed the scenario of an elevated plus-maze (EPM) using VR, which is widely used in animal models to assess unconditioned anxiety. This task allowed us to analyze the behavioral, psychophysiological (heart rate and electrodermal activity), and hormonal response (salivary cortisol and Alpha-amylase) to this stressful situation in different moments (before VR task (anticipation), at the end of the task and 10 minutes later) in young people with problematic alcohol use (AU, n = 27), alcohol combined with cannabis consumption (AU + C, n = 10), as well as in a control group (CO, n = 33). Behavioral analysis revealed that the AU group displayed fewer entries into open arms than the CO group, whereas both experimental groups spent less time at the end of the open arms, as well as lower time by look down index compared to the CO group. Moreover, our VR EPM induced different psychophysiological responses in the different moments measured. In general, electrodermal activity seemed to be a good biomarker of recovery from a stressful situation, as once the exposure to the stressful situation ended, the AU + C group took longer to recover compared to the CO group. Regarding hormonal analyses, we observed a similar response pattern in all groups suggesting that our VR task was able to activate both stress systems. The alpha-amylase to cortisol ratio, proposed as a biomarker of stress systems dysregulation, was higher in the group of young participants with alcohol abuse. Interestingly, our VR EPM was able to induce a slight alcohol craving in both experimental groups. In conclusion, our results suggest certain subtle behavioral and physiological differences that could be used to detect young individuals at risk of future severe addictions or other stress-related comorbidities. Moreover, it could help us to develop prevention strategies focused on emotional, cognitive, and psychophysiological aspects.

Understanding the relationship between apathy, cognition and functional outcome in schizophrenia: The significance of an ecological assessment

In recent years there has been an increasing interest in understanding the role apathy plays in mediating the relationship between cognitive impairment and functional outcome. In general, most studies measure cognition with traditional cognitive tests that give explicit instructions and guide the participants toward generating a response. However, given that apathy is defined by a decrease in self-initiated behavior, it is crucial to evaluate cognition with ecological tasks that do not explicitly direct the patient´s motivation to generate behaviors to assess the actual effect. This study investigated whether an ecological cognitive assessment (the Jansari Executive Function Assessment, JEF^©) would uniquely contribute to the relationship between cognition, apathy, and functional outcome in schizophrenia. The Apathy Evaluation Scale (AES), neuropsychological tests and the JEF^© were administered to 20 patients with schizophrenia. Hierarchical multiple regression and mediation analysis were performed to test the associations between the variables of interest. Results showed that JEF^© explained a significant portion of the variance in AES (25%). In addition, apathy explained 36% of the variance in functional outcome. However, AES did not mediate between cognition and functional outcome. Our results highlight the importance of assessing cognition with tasks that require integration of cognitive functions needed for real life demands.

DRUG-IMPAIRED DRIVING AND TRAFFIC COLLISIONS: STUDY ON A CROSS SECTION OF THE ITALIAN POPULATION

The present study focuses on the association between road accidents and the presence of drugs of abuse markers in the biological fluids of the drivers. Biological fluids collected from 1,236 drivers involved in road accidents (54 fatal and 1,182 non-fatal crashes) in the Rome area were analysed for alcohol and psychotropic drugs, as required by judicial authorities. The substance most frequently detected was alcohol (in 19% of non-fatal and 32% of fatal crashes), followed by cannabinoids (12% of non-fatal crashes) and cocaine (9% of non-fatal and 20% of fatal crashes). The results obtained for cocaine and cannabinoids in blood and urine were compared. We observed the absence or low concentrations of the active drug in blood (cocaine was often below 5 ng/mL and THC below 1 ng/mL), whereas urinary concentrations of metabolites were generally high (benzoylecgonine 250 - above 5000 ng/mL, THCCOOH 15-270 ng/mL). The risk of being involved in a road accident if cocaine or cannabis markers were present in the urine specimens was evaluated compared to a control population. The odds ratios calculated, being 8.13 for cannabis and 5.32 for cocaine, suggest a strong association between the presence of these drugs in the urine of drivers and traffic accidents, regardless of their presence in blood samples. The present data suggest that the chance of being involved in a road accident is higher than in the control population even if the subject is no longer "under the influence" of cannabis or cocaine at the time of the accident.

Recreational drug use and prospective memory

Prospective memory (PM) impairment in recreational drug users has been documented in recent years. However, most studies on the effects of drugs on PM contain several methodological challenges, such as small sample size (< 100 participants), unrepresentative sample type (e.g., student or patient), short abstinence period (< 7 days), and lack of control of potential confounds (e.g., sleep and IQ). The present study investigated the possible consequences of recreational drug use on prospective memory, using self-report and lab-based prospective memory measures while overcoming the methodological challenges. The sample was composed of 47 non-users (27 females, age range from 18 to 50 +) and 53 drug users (21 females, age range from 18 to 50 +). Recreational drug users reported significantly more deficits in the long-term episodic, short-term habitual, and internally cued PM failures subscales of the Prospective Memory Questionnaire. However, these deficits were eliminated after controlling for covariates (e.g., age, sleep quality, general health, alcohol usage). Recreational drug users also performed worse than non-users in the short-term, long-term, event-based, and time-based PM subscales of the Royal Prince Alfred Prospective Memory Test. These results remained significant after controlling for the covariates. Drug users demonstrated greater impairments on time-based and long-term PM tasks thought to be linked with executive functioning. Taken together, the present study provides further support for recreational drug-related deficits in PM and highlights a dissociation between self-report and lab-based PM measures.

Virtual reality assessment of daily life executive functions in mood disorders: associations with neuropsychological and functional measures

BACKGROUND

Mood disorders are often accompanied by cognitive difficulties that impede patients' functional capacity. However, neuropsychological tests provide limited insight into patients' ability to tackle daily life cognitive challenges. To address this challenge, we investigated the sensitivity and validity of the Jansari assessment of Executive Functions (JEF©) virtual reality test in patients with mood disorders and its associations with functional capacity.

METHODS

In total, 21 patients with bipolar disorder or unipolar disorder in full or partial remission and 29 healthy control participants were recruited for the study. Participants attended one test session during which they underwent diagnostic assessments, mood ratings and assessments with JEF©, a battery of standard neuropsychological tests (RAVLT, Trial Making A and B, Fluency tests, letter-number sequencing and RBANS digit span and coding tests) and functional capacity measures (UPSA-B and FAST).

RESULTS

Patients showed impaired executive functions on JEF© compared to the control group. Relative to the control group, patients were also impaired on neuropsychological sub-composite scores of executive function, verbal memory and processing speed as well as on a global cognition composite score. In addition, JEF© scores predicted performance on a global cognition composite based on neuropsychological tests, and a performance-based measure of functional capacity.

LIMITATIONS

This study had a relatively small sample size and included a mixed group of patients with unipolar or bipolar disorder.

CONCLUSIONS

JEF© is a sensitive and valid measure of daily life executive impairments in patients with mood disorders that is associated with functional capacity.

Investigating the Residual Effects of Chronic Cannabis Use and Abstinence on Verbal and Visuospatial Learning

Rationale: Regular cannabis users have been shown to differ from non-using controls in learning performance. It is unclear if these differences are specific to distinct domains of learning (verbal, visuospatial), exacerbate with extent of cannabis exposure and dissipate with sustained abstinence. Objective: This study examines different domains of learning (verbal, visuospatial) in current and abstaining cannabis users, and the role of chronicity of use. Methods: In a cross-sectional design, we examined 127 psychiatrically healthy participants (65 female) with mean aged of 34 years. Of these, 69 individuals were current regular cannabis users (mean 15 years use), 12 were former cannabis users abstinent for ~2.5 yrs (after a mean of 16 years use), and 46 were non-cannabis using controls. Groups were compared on verbal learning performance assessed via the California Verbal Learning Test (CVLT-II) and for visuospatial learning measured with the Brown Location Test (BLT). We explored the association between CVLT/BLT performance and cannabis use levels in current and former users. Results: Current cannabis use compared to non-use was associated with worse performance on select aspects of verbal learning (Long Delay Cued Recall) and of visuospatial learning (Retroactive Interference and LD Rotated Recall). Prolonged abstinence was associated with altered verbal learning but intact visuospatial learning. There were non-significant correlations between distinct cannabis use measures, age and learning in both current and former users. Conclusions: Our findings suggest cannabis use status (current use, former use) affects different domains of learning (verbal and visuospatial) in a distinct fashion. These findings might be accounted for in the design of cognitive interventions aimed to support abstinence in cannabis users.

Hebrew version of the Jansari assessment of Executive Functions for Children (JEF-C©): Translation, adaptation and validation

The Jansari assessment of Executive Functions for Children (JEF-C^©) is a non-immersive computerized assessment of executive functions (EFs). This study aimed to create a cross-culturally adapted Hebrew version, JEF-C(H)^© and to assess reliability and validity in the Israeli context. Forty typically developing Israeli children and adolescents, aged 11-18 years, were assessed with JEF-C(H)^©. In addition, participants and their parents filled in the Behaviour Rating Inventory of Executive Function (BRIEF). JEF-C(H)^© was found to be feasible in Israeli children and adolescents. The internal consistency was acceptable (Cronbach's alpha = 0.79). Most of the JEF-C(H)^© subtests and the Average score showed significant positive moderate to high correlations with age, ranging from 0.40 to 0.78 demonstrating construct validity. Multiple significant correlations were also found between the JEF-C(H)^© Average score and the BRIEF indices as well as total score in the Parent and Self-report questionnaires. These preliminary findings support the reliability and validity of this version. Current findings demonstrate the potential clinical utility of JEF-C(H)^© as an ecologically valid tool for Israeli children and adolescents in the assessment of EFs.

Illegal drug use and prospective memory: A systematic review

Illegal drug use is proposed to interfere with neurobiological functioning by damaging the neurotransmitter communication systems that are believed to be responsible for cognitive abilities, including perception, attention, and memory. This review specifically examined effects of illegal drug use on prospective memory (PM) - memory for future actions. Twenty- seven studies spanning 14 years were included in this review which were divided into two broad categories based on testing methods used: self-report and lab-based testing methods. The quality of the included studies was assessed across five categories: sample type, sample size, abstinence period, testing methods and control for confounding factors. The overall quality of evidence was good for six studies and moderate for sixteen studies and low for five studies. The results from the studies employing self-report were inconsistent as illegal drug users exhibited PM deficits in some studies, but not in others. However, the studies with lab-based testing methods demonstrated more consistent findings with illegal drug users scoring worse than non-users on various PM tests. There were also consistent findings on the link between the dosage of drug taken and level of PM deficit. Based on the literature, there is moderate evidence that illegal drug use impairs PM ability. We recommend that further lab-based studies be conducted to assess dose-response effects on drug-specificity.

Is Cannabis Harmless? Focus on Brain Function

BACKGROUND

The degree to which cannabis use causes long term harm to mental functioning is contentious.

OBJECTIVE

To determine the evidence for residual and long term effects of cannabis use on mental functions.

METHOD

Comprehensively review human studies addressing detrimental effects on human mental and life functioning.

RESULTS

Heavy use causes immediate effects on perception, mood and sedation, but also deficits in cognitive ability. But cessation following heavy use has withdrawal effects and is associated with residual effects on cognition that may last for several weeks. Heavy use also raises the risk of impoverishment of life outcomes and a decline in socioeconomic status as well as the risk of mental health problems. Young age at the start of heavy cannabis use causes a risk of lifelong detrimental effects, and as a worst case together with genetic vulnerability exacerbate a predisposition to schizophrenia.

CONCLUSION

Heavy regular use of cannabis that begins in adolescence heightens the risk of longterm impairment of life and mental functioning.

Joint effects of stress and chronic cannabis use on prospective memory

RATIONALE

Prospective memory pervades our daily lives and failures can have detrimental consequences. This ability to execute delayed intentions may be impacted by stress, yet few studies have examined these effects. Moreover, as many cannabis users report using cannabis to cope with stress, it is important to understand how stress impacts memory in cannabis users.

OBJECTIVES

We assessed the effects of acute and chronic stress on prospective memory to examine whether stress differentially impacts prospective memory in cannabis users vs. non-users.

METHODS

Forty cannabis users and 42 non-users were assigned an episodic and a habitual prospective memory test before completing either the stress or no stress condition of the Maastricht Acute Stress Test (MAST). Participants were instructed to execute the habitual test during the MAST and the episodic test shortly after the MAST. Chronic stress was measured using the Perceived Stress Scale, and acute stress was measured using subjective ratings and cortisol.

RESULTS

There was a main effect of acute stress indicating that stress detrimentally impacted habitual prospective memory performance. Although there was not a significant stress x cannabis interaction, further planned comparisons indicated the habitual prospective memory impairment was selective to cannabis users. There were also significant negative correlations between (i) episodic prospective memory and both subjective stress as well as chronic stress, and (ii) habitual prospective memory and change in subjective stress.

CONCLUSIONS

This study is the first to reveal detrimental effects of acute stress on prospective memory performance, which may be exacerbated in cannabis users.

The effects of licit and illicit recreational drugs on prospective memory: a meta-analytic review

RATIONALE

There are no recent reports summarising the magnitude of prospective memory (PM) impairments in recreational drug users.

OBJECTIVE

We performed a meta-analysis of studies (with a parallel group design) examining PM performance in users of common recreational drugs (including alcohol and tobacco) who were not intoxicated during testing. Studies were also evaluated for the presence of methodological bias.

METHODS

Twenty-seven studies were included in the meta-analysis following literature searches of MEDLINE, EMBASE and PsycINFO. Effect sizes (standardised mean difference; SMD) were calculated separately for the effects of alcohol, cannabis, ecstasy, methamphetamine and tobacco use. The influences of drug use and study characteristics on effect sizes were explored using meta-regressions. Sources of study bias were also assessed.

RESULTS

Heavy drinkers and regular drug users tended to perform worse than controls on event and time-based PM tasks. Effect sizes (standardised mean differences; SMDs) for event-based PM impairment across the different drug-using groups/heavy drinkers ranged between - 1.10 and - 0.49, with no 95% CI crossing 0.00. SMDs for time-based PM ranged between - 0.98 and - 0.70. Except for the CIs associated with the ES for smokers' time-based PM performance, no CIs crossed 0.00.

CONCLUSIONS

Although all drug-using groups showed moderate-large impairments in event and time-based PM, effect sizes had low precision and moderate-high levels of heterogeneity. In addition, several methodological and reporting issues were identified in the majority of studies. As such, considerable uncertainty remains regarding the role of confounds and the magnitude of PM impairments in non-intoxicated recreational drug users.

Episodic foresight deficits in regular, but not recreational, cannabis users

BACKGROUND

Cannabis use is associated with a range of neurocognitive deficits, including impaired episodic memory. However, no study to date has assessed whether these difficulties extend to episodic foresight, a core component of which is the ability to mentally travel into one's personal future. This is a particularly surprising omission given that episodic memory is considered to be critical to engage episodic foresight.

AIMS

In the present study, we provide the first test of how episodic foresight is affected in the context of differing levels of cannabis use, and the degree to which performance on a measure of this construct is related to episodic memory.

RESULTS

Fifty-seven regular cannabis users (23 recreational, 34 regular) and 57 controls were assessed using an adapted version of the Autobiographical Interview. The results showed that regular-users exhibited greater impairment of episodic foresight and episodic memory than both recreational-users and cannabis-naïve controls.

CONCLUSIONS

These data therefore show for the first time that cannabis-related disruption of cognitive functioning extends to the capacity for episodic foresight, and they are discussed in relation to their potential implications for functional outcomes in this group.

Verbal Memory Deficits in OEF/OIF/OND Veterans Exposed to Blasts at Close Range

OBJECTIVES

This study investigated the relationship between close proximity to detonated blast munitions and cognitive functioning in OEF/OIF/OND Veterans.

METHODS

A total of 333 participants completed a comprehensive evaluation that included assessment of neuropsychological functions, psychiatric diagnoses and history of military and non-military brain injury. Participants were assigned to a Close-Range Blast Exposure (CBE) or Non-Close-Range Blast Exposure (nonCBE) group based on whether they had reported being exposed to at least one blast within 10 meters.

RESULTS

Groups were compared on principal component scores representing the domains of memory, verbal fluency, and complex attention (empirically derived from a battery of standardized cognitive tests), after adjusting for age, education, PTSD diagnosis, sleep quality, substance abuse disorder, and pain. The CBE group showed poorer performance on the memory component. Rates of clinical impairment were significantly higher in the CBE group on select CVLT-II indices. Exploratory analyses examined the effects of concussion and multiple blasts on test performance and revealed that number of lifetime concussions did not contribute to memory performance. However, accumulating blast exposures at distances greater than 10 meters did contribute to poorer performance.

CONCLUSIONS

Close proximity to detonated blast munitions may impact memory, and Veterans exposed to close-range blast are more likely to demonstrate clinically meaningful deficits. These findings were observed after statistically adjusting for comorbid factors. Results suggest that proximity to blast should be considered when assessing for memory deficits in returning Veterans. Comorbid psychiatric factors may not entirely account for cognitive difficulties. (JINS, 2018, 24, 466-475).

Non-Dependent and Dependent Daily Cannabis Users Differ in Mental Health but Not Prospective Memory Ability

Research suggests that daily cannabis users have impaired memory for past events, but it is not clear whether they are also impaired in prospective memory (PM) for future events. The present study examined PM in daily cannabis users who were either dependent (n = 18) or non-dependent (n = 18), and compared them with non-using controls (n = 18). The effect of future event simulation (FES) on PM performance was also examined. Participants were matched across groups on age, gender, and highest level of education. The virtual week (VW) was used to objectively assess PM abilities, both at baseline and following FES. Other measures used were: cannabis use variables, immediate and delayed prose recall, phonemic and category fluency, spot-the-word test (premorbid intelligence), Beck Depression Inventory, Beck Anxiety Inventory, and a measure of schizotypy (Oxford-Liverpool Inventory of Feelings and Experiences: unusual experiences subscale). No group differences were found in PM performance on the VW, and FES did not improve PM performance in any group. Dependent cannabis users scored higher on depression, anxiety, and schizotypy than both other groups with non-dependent cannabis users scoring at a similar level to controls. There were no group differences in alcohol use. Findings suggest that when carefully matched on baseline variables, and not differing in premorbid IQ or alcohol use, young, near-daily cannabis users do not differ from non-using controls in PM performance.

Assessment of executive functions in children and adolescents with acquired brain injury (ABI) using a novel complex multi-tasking computerised task: The Jansari assessment of Executive Functions for Children (JEF-C©)

Objectives: The Jansari assessment of Executive Functions for Children (JEF-C^©) is a new non-immersive computerised assessment of executive functions. The objectives of the study were to test the feasibility and validity of JEF-C^© in children and adolescents with acquired brain injury (ABI). Methods: Twenty-nine patients with ABI aged 10-18 years and 30 age-and gender-matched controls were tested. Participants performed JEF-C^©, Wechsler Abbreviated Scale of Intelligence (WASI) and the Behavioural Assessment of the Dysexecutive Syndrome for Children (BADS-C), while parents completed the Behaviour Rating Inventory of Executive Function (BRIEF) questionnaire. Results: The JEF-C^© task proved feasible in patients with ABI. The internal consistency was medium (Cronbach's alpha = 0.62 and significant intercorrelations between individual JEF-C^© constructs). Patients performed significantly worse than controls on most of the JEF-C^© subscales and total score, with 41.4% of participants with ABI classified as having severe executive dysfunction. No significant correlations were found between JEF-C^© total score, the BRIEF indices, and the BADS-C. Significant correlations were found between JEF-C^© and demographic characteristics of the sample and intellectual ability, but not with severity/medical variables. Conclusion: JEF-C^© is a playful complex task that appears to be a sensitive and ecologically valid assessment tool, especially for relatively high-functioning individuals.

Longitudinal changes in cognition in young adult cannabis users

INTRODUCTION

Adolescent cannabis use (CU) is associated with impaired attention, executive function, and verbal learning/memory. These associations are generally observed in cross-sectional studies. Longitudinal studies of cannabis users are lacking.

METHOD

The present study examines associations between CU and cognition over time in chronic daily adolescent-onset CUs, as compared to nonusing controls. Both groups completed a neuropsychological battery at study intake and again 2 years later.

RESULTS

Baseline group differences have been published and indicated deficits in verbal learning and memory, motivated decision-making, planning, and working memory in CUs. In this follow-up report, the longitudinal performance of users is compared to that of sustained nonusers using the same battery. At follow-up, the majority of CUs continued to report regular and heavy cannabis use. Relative impairments in the domains of working memory, planning and verbal memory remained stable, suggesting that these are enduring vulnerabilities associated with continued CU during young adulthood. Improvements in motivated decision-making were evident in both groups. In addition, CUs demonstrated relatively better performance on short-duration speeded tasks. An earlier age of CU onset was associated with poorer verbal learning and memory and planning performance over time.

CONCLUSIONS

Verbal learning and memory and planning processes, as well as their neural correlates, merit further scrutiny within etiological models of cannabis-induced cognitive impairments.

Using Virtual Reality to investigate multitasking ability in individuals with frontal lobe lesions

Individuals with lesions in the prefrontal cortex often show impairments with the organisation of their behaviour in everyday life. These difficulties can be hard to detect using structured formal tests. The objective of this study was to use Virtual Reality (VR) to explore the multitasking performance of individuals with focal frontal lobe lesions, specifically using the Jansari assessment of Executive Functions (JEF^©). Nineteen individuals with frontal lobe lesions were compared with 19 matched controls on the test and a group of commonly used clinical measures of neuropsychological functioning, as well as questionnaire measures of everyday activity, anxiety and depression. There was a significant difference between groups on the overall JEF^© score and on five of the eight individual constructs, namely the planning, creative thinking, adaptive thinking, event-based Prospective Memory (PM) and time-based PM constructs. There were no differences between groups on the non-VR EF individual measures apart from on one EF control measure, Trail Making A. These results demonstrate the potential clinical utility of the JEF^© and highlight the value of ecologically valid VR measures in detecting impairments in EF in individuals with frontal lobe lesions.

Is binding decline the main source of the ageing effect on prospective memory? A ride in a virtual town

Objective: This study was designed to improve our understanding of prospective memory (PM) changes in ageing, and to identify the cognitive correlates of PM decline, using a virtual environment, to provide a more realistic assessment than traditional laboratory tasks.

Design: Thirty-five young and 29 older individuals exposed to a virtual town were asked to recall three event-based intentions with a strong link between prospective and retrospective components, three event-based intentions with a weak link, and three time-based intentions. They also underwent retrospective episodic memory, executive functions, binding in working memory, processing speed, and time estimation assessments.

Results: Older individuals recalled fewer intentions than young adults. While age-related PM decline affected the recall of both prospective and retrospective components, the recall of the latter seemed more challenging for older individuals when the link was weak. This PM decline was linked to an age-related decline in the binding process in working memory, as well as in processing speed, executive functioning, and episodic memory, depending on the nature of intentions.

Conclusion: PM appears to be sensitive to ageing, even when the device is thought to be ecological. This decline is particularly pronounced when controlled processes are needed.

[Consumption of cannabis in adolescents]

Over the past 10 years, the consumption of cannabis among adolescents has dramatically increased. Today, adolescent cannabis use is a major public health problem. Two forms of cannabis are commonly smoked: herb (marijuana) and resin. These forms have a high concentration of tetrahydrocannabinol, the active molecule of cannabis. Recent research has helped understand how the cannabinoid system works. This system combines specific receptors and specific molecules: the endocannabinoids. The effects of cannabis use are now well documented. Some adolescents report subjective positive effects. They use it not only on a recreational basis, but also to deal with their emotions. Over the long term, cannabis increases the risk of depression and schizophrenia for those adolescents who are at risk. Use, misuse, and dependence are frequently associated with heavy psychopathologic problems such as vulnerability and depression. Many cannabis dependence psychotherapies have shown their efficacy and efficiency. Motivational interviews, cognitive behavioral therapy, multidimensional family therapy (MDFT), and residential treatment have proved highly effective. MDFT seems very effective, especially in cases of heavy use.

Initial feasibility and validity of a prospective memory training program in a substance use treatment population

Individuals with substance use disorders have shown deficits in the ability to implement future intentions, called prospective memory. Deficits in prospective memory and working memory, a critical underlying component of prospective memory, likely contribute to substance use treatment failures. Thus, improvement of prospective memory and working memory in substance use patients is an innovative target for intervention. We sought to develop a feasible and valid prospective memory training program that incorporates working memory training and may serve as a useful adjunct to substance use disorder treatment. We administered a single session of the novel prospective memory and working memory training program to participants (n = 22; 13 men, 9 women) enrolled in outpatient substance use disorder treatment and correlated performance to existing measures of prospective memory and working memory. Generally accurate prospective memory performance in a single session suggests feasibility in a substance use treatment population. However, training difficulty should be increased to avoid ceiling effects across repeated sessions. Consistent with existing literature, we observed superior performance on event-based relative to time-based prospective memory tasks. Performance on the prospective memory and working memory training components correlated with validated assessments of prospective memory and working memory, respectively. Correlations between novel memory training program performance and established measures suggest that our training engages appropriate cognitive processes. Further, differential event- and time-based prospective memory task performance suggests internal validity of our training. These data support the development of this intervention as an adjunctive therapy for substance use disorders. (PsycINFO Database Record

Ecological Assessment of Executive Functions: A New Virtual Reality Paradigm

Acquired brain injury (ABI) can lead to a constellation of higher-order executive problems, which can impact significantly on everyday behaviour. While some neuropsychological assessments are able to measure these impairments objectively, increasingly, clinicians are finding that a subset of their patients passes these tests while still exhibiting difficulties in day-to-day living. Calls have therefore been made to develop assessments that are more sensitive and that are more ecologically valid. In this study, in Experiment 1, a multiple errands task (MET) based around a business office was created to assess concurrently nine aspects of executive functioning (planning, prioritisation, selective-thinking, creative-thinking, adaptive-thinking, multi-tasking, action-based prospective memory (PM), event-based PM and time-based PM). This new paradigm, the Jansari assessment of Executive Functions (JEF©) showed a significant difference between six individuals with ABI and matched healthy controls; further, it showed that across the nine constructs there was a range of performance. In Experiment 2, JEF©was recreated in a virtual environment resembling a computer game, and it was found that this version significantly differentiated between 17 individuals with ABI and 30 healthy controls. These results suggest that the virtual version of JEF©could be used as a new assessment of executive function. The profile of performance across the nine constructs for each individual provides a wealth of objective information that could potentially inform targeted rehabilitation.

Task importance affects event-based prospective memory performance in adults with HIV-associated neurocognitive disorders and HIV-infected young adults with problematic substance use

Two experiments were conducted to examine the effects of task importance on event-based prospective memory (PM) in separate samples of adults with HIV-associated neurocognitive disorders (HAND) and HIV-infected young adults with substance use disorders (SUD). All participants completed three conditions of an ongoing lexical decision task: (1) without PM task requirements; (2) with PM task requirements that emphasized the importance of the ongoing task; and (3) with PM task requirements that emphasized the importance of the PM task. In both experiments, all HIV+ groups showed the expected increase in response costs to the ongoing task when the PM task's importance was emphasized. In Experiment 1, individuals with HAND showed significantly lower PM accuracy as compared to HIV+ subjects without HAND when the importance of the ongoing task was emphasized, but improved significantly and no longer differed from HIV+ subjects without HAND when the PM task was emphasized. A similar pattern of findings emerged in Experiment 2, whereby HIV+ young adults with SUD (especially cannabis) showed significant improvements in PM accuracy when the PM task was emphasized. Findings suggest that both HAND and SUD may increase the amount of cognitive attentional resources that need to be allocated to support PM performance in persons living with HIV infection.

Prospective memory impairment in long-term opiate users

RATIONALE

Opiate use is associated with a range of neurological and cognitive deficits. However, to date, no studies have assessed whether these cognitive deficits extend to the ability to perform intended actions in the future (i.e. prospective memory). Reduced ability in this area might be anticipated due to impaired executive functions and episodic memory associated with long-term opiate use.

OBJECTIVES

The main objectives of this study are to assess the performance of long-term opiate users on a laboratory measure of prospective memory which closely simulates the types of prospective memory tasks encountered in everyday life ('Virtual Week') and to investigate the extent to which prospective memory performance is related to executive functions and episodic memory ability.

METHODS

Twenty-six long-term heroin users enrolled in an opiate substitution program, and 30 controls with no previous history of drug use were tested on Virtual Week. Retrospective memory and executive functions were also assessed.

RESULTS

Long-term opiate users were significantly impaired on prospective memory performance compared with controls (p = 0.002, η(2) p = 0.17), and these deficits did not vary as a function of prospective memory task type (regular, irregular, event, time). The findings also suggest that retrospective memory difficulties contribute to the prospective memory difficulties seen in opiate users (r s  = 0.78, p < 0.001) but that executive dysfunction is less influential.

CONCLUSIONS

Prospective memory is sensitive to long-term opiate use. Importantly, opiate users suffer from generalised deficits in prospective memory, regardless of the task demands, which may have significant implications for day-to-day functioning. These results may therefore contribute to the development of clinical intervention strategies to reduce the negative impact of prospective memory failures in daily life.

Neurocognition in college-aged daily marijuana users

BACKGROUND

Marijuana is the most commonly used illicit substance in the United States. Use, particularly when it occurs early, has been associated with cognitive impairments in executive functioning, learning, and memory.

METHOD

This study comprehensively measured cognitive ability as well as comorbid psychopathology and substance use history to determine the neurocognitive profile associated with young adult marijuana use. College-aged marijuana users who initiated use prior to age 17 (n = 35) were compared to demographically matched controls (n = 35).

RESULTS

Marijuana users were high functioning, demonstrating comparable IQs to controls and relatively better processing speed. Marijuana users demonstrated relative cognitive impairments in verbal memory, spatial working memory, spatial planning, and motivated decision making. Comorbid use of alcohol, which was heavier in marijuana users, was unexpectedly found to be associated with better performance in some of these areas.

CONCLUSIONS

This study provides additional evidence of neurocognitive impairment in the context of adolescent and young adult marijuana use. Findings are discussed in relation to marijuana's effects on intrinsic motivation and discrete aspects of cognition.

Marijuana: current concepts(†)

Marijuana (cannabis) remains a controversial drug in the twenty-first century. This paper considers current research on use of Cannabis sativa and its constituents such as the cannabinoids. Topics reviewed include prevalence of cannabis (pot) use, other drugs consumed with pot, the endocannabinoid system, use of medicinal marijuana, medical adverse effects of cannabis, and psychiatric adverse effects of cannabis use. Treatment of cannabis withdrawal and dependence is difficult and remains mainly based on psychological therapy; current research on pharmacologic management of problems related to cannabis consumption is also considered. The potential role of specific cannabinoids for medical benefit will be revealed as the twenty-first century matures. However, potential dangerous adverse effects from smoking marijuana are well known and should be clearly taught to a public that is often confused by a media-driven, though false message and promise of benign pot consumption.

The K2/Spice phenomenon: emergence, identification, legislation and metabolic characterization of synthetic cannabinoids in herbal incense products

In 2008, the European Monitoring Center for Drugs and Drug Addiction (EMCDDA) detected unregulated, psychoactive synthetic cannabinoids (SCBs) in purportedly all-natural herbal incense products (often known as K2 or Spice) that were being covertly abused as marijuana substitutes. These drugs, which include JWH-018, JWH-073 and CP-47,497, bind and activate the cannabinoid receptors CB1R and CB2R with remarkable potency and efficacy. Serious adverse effects that often require medical attention, including severe cardiovascular, gastrointestinal and psychiatric sequelae, are highly prevalent with SCB abuse. Consequently, progressively restrictive legislation in the US and Europe has banned the distribution, sale and use of prevalent SCBs, initiating cycles in which herbal incense manufacturers replace banned SCBs with newer unregulated SCBs. The contents of the numerous, diverse herbal incense products was unknown when SCB abuse first emerged. Furthermore, the pharmacology of the active components was largely uncharacterized, and confirmation of SCB use was hindered by a lack of known biomarkers. These knowledge gaps prompted scientists across multiple disciplines to rapidly (1) monitor, identify and quantify with chromatography/mass spectrometry the ever-changing contents of herbal incense products, (2) determine the metabolic pathways and major urinary metabolites of several commonly abused SCBs and (3) identify active metabolites that possibly contribute to the severe adverse effect profile of SCBs. This review comprehensively describes the emergence of SCB abuse and provides a historical account of the major case reports, legal decisions and scientific discoveries of the "K2/Spice Phenomenon". Hypotheses concerning potential mechanisms SCB adverse effects are proposed in this review.

Effects of cannabis on neurocognitive functioning: recent advances, neurodevelopmental influences, and sex differences

Decades of research have examined the effects of cannabis on neurocognition. Recent advances in this field provide us with a better understanding of how cannabis use influences neurocognition both acutely (during intoxication) and non-acutely (after acute effects subside). Evidence of problems with episodic memory is one of the most consistent findings reported; however, several other neurocognitive domains appear to be adversely affected by cannabis use under various conditions. There is significant variability in findings across studies, thus a discussion of potential moderators is increasingly relevant. The purpose of this review was to 1) provide an update on research of cannabis' acute and non-acute effects on neurocognition, with a focus on findings since 2007 and 2) suggest and discuss how neurodevelopmental issues and sex differences may influence cannabis effects on neurocognition. Finally we discuss how future investigations may lead to better understanding of the complex interplay among cannabis, stages of neurodevelopment, and sex on neurocognitive functioning.

Investigating the impact of nicotine on executive functions using a novel virtual reality assessment

AIMS

Nicotine is known to enhance aspects of cognitive functioning in abstinent smokers, but the effects on specific areas of executive functions and in non-smokers are inconclusive. This may be due in part to the poor sensitivity of tests used to assess executive functions. This study used a new virtual reality assessment of executive functions known as JEF (the Jansari assessment of Executive Functions) to address this issue.

DESIGN

A 2 × 2 design manipulating group (smokers and never-smokers) and drug [nicotine (4 mg for smokers; 2 mg for never smokers) versus placebo gum].

SETTING

School of Psychology; University of East London.

PARTICIPANTS

Seventy-two participants (aged 18-54 years): 36 minimally deprived (2 hours) smokers and 36 never-smokers.

MEASUREMENTS

Components of executive function were measured using the virtual reality paradigm JEF, which assesses eight cognitive constructs simultaneously as well as providing an overall performance measure.

FINDINGS

Univariate analyses of variance revealed that nicotine improved overall JEF performance, time-based prospective memory and event-based prospective memory in smokers (P < 0.01), but not in never-smokers. Action-based prospective memory was enhanced in both groups (P < 0.01) and never-smokers out-performed smokers on selective thinking and adaptive thinking (P < 0.01).

CONCLUSIONS

Executive functioning and prospective memory as aspects of cognitive performance can be enhanced by nicotine gum in smokers who have abstained for as little as 2 hours.