Mediated and moderated effects of neurocognitive impairment on outcomes of treatment for substance dependence and major depression

Chronic ethanol exposure produces long-lasting, subregion-specific physiological adaptations in RMTg-projecting mPFC neurons

Chronic ethanol exposure produces neuroadaptations in the medial prefrontal cortex (mPFC) that are thought to facilitate maladaptive behaviors that interfere with recovery from alcohol use disorder. Despite evidence that different cortico-subcortical projections play distinct roles in behavior, few studies have examined the physiological effects of chronic ethanol at the circuit level. The rostromedial tegmental nucleus (RMTg) is functionally altered by chronic ethanol exposure. Our recent work identified dense input from the mPFC to the RMTg, yet the effects of chronic ethanol exposure on this circuitry is unknown. In the current study, we examined physiological changes after chronic ethanol exposure in prelimbic (PL) and infralimbic (IL) mPFC neurons projecting to the RMTg. Adult male Long-Evans rats were injected with fluorescent retrobeads into the RMTg and rendered dependent using a 14-day chronic intermittent ethanol (CIE) vapor exposure paradigm. Whole-cell patch-clamp electrophysiological recordings were performed in fluorescently-labeled (RMTg-projecting) and -unlabeled (projection-undefined) layer 5 pyramidal neurons 7-10 days following ethanol exposure. CIE exposure significantly increased intrinsic excitability as well as spontaneous excitatory and inhibitory postsynaptic currents (sE/IPSCs) in RMTg-projecting IL neurons. In contrast, no lasting changes in excitability were observed in RMTg-projecting PL neurons, although a CIE-induced reduction in excitability was observed in projection-undefined PL neurons. CIE exposure also increased the frequency of sEPSCs in RMTg-projecting PL neurons. These data uncover novel subregion- and circuit-specific neuroadaptations in the mPFC following chronic ethanol exposure and reveal that the IL mPFC-RMTg projection is uniquely vulnerable to long-lasting effects of chronic ethanol exposure. This article is part of the Special Issue on "PFC circuit function in psychiatric disease and relevant models".

Performance on Cognitive Screening Tests and Long-Term Substance Use Outcomes in Patients with Polysubstance Use Disorder

INTRODUCTION

Cognitive impairments among patients with substance use disorders are prevalent and associated with adverse treatment outcomes. However, knowledge of the predictive value of broad cognitive screening instruments on long-term treatment outcomes is limited. The present study aimed to examine the predictive value of measures from the Montreal Cognitive Assessment® (MoCA®), Wechsler Abbreviated Scale of Intelligence (WASI), and the Behaviour Rating Inventory of Executive Function - Adult version (BRIEF-A) on self-reported long-term substance use and abstinence in patients with polysubstance use disorders (pSUD).

METHODS

A cohort (N = 164) of patients with pSUD who started a new treatment sequence in the Stavanger University Hospital catchment area were recruited and followed prospectively for 5 years. Participants completed neurocognitive testing with the MoCA®, WASI, and BRIEF-A at inclusion and were categorized as cognitively impaired or non-impaired according to recommended cut-off values. The sum score of the items from the Drug Use Disorders Identification Test Consumption scale (DUDIT-C) was used as a measure of substance use outcome 1 and 5 years after inclusion. We defined substance abstinence (DUDIT-C = 0) and heavy substance use (DUDIT-C ≥7) to determine whether cognitive impairments measured by the respective instruments were associated with and could predict abstinence and heavy substance use 1 and 5 years after baseline.

RESULTS

At the 1-year follow-up, 54% of the total sample reported total abstinence from substances. Conversely, 31% presented heavy substance use. At 5 years, 64% of the total sample reported abstinence from substances, while 25% presented heavy substance use. The results showed a statistically significant association between cognitive impairment defined from MoCA® and higher continuous scores on DUDIT-C at 1-year follow-up. There were no differences in substance abstinence or heavy substance use between patients with and without cognitive impairment at the 1- and 5-year follow-ups. Furthermore, cognitive impairment did not explain substance abstinence or heavy substance use at the 1- and 5-year follow-ups.

CONCLUSION

Generally, individuals with pSUD may be burdened and lack psychosocial resources to such an extent that cognitive functioning plays a subordinate role in long-term recovery. The present study suggests that results on screening tools assessing broad cognitive domains at treatment initiation have limited clinical value in predicting long-term substance use outcomes. There is a need to establish clinically viable instruments to assess cognitive functions with well-established clinical and ecological validity in the SUD population.

The Effect of Chronic Alcohol on Cognitive Decline: Do Variations in Methodology Impact Study Outcome? An Overview of Research From the Past 5 Years

Excessive alcohol use is often associated with accelerated cognitive decline, and extensive research using animal models of human alcohol consumption has been conducted into potential mechanisms for this relationship. Within this literature there is considerable variability in the types of models used. For example, alcohol administration style (voluntary/forced), length and schedule of exposure and abstinence period are often substantially different between studies. In this review, we evaluate recent research into alcohol-induced cognitive decline according to methodology of alcohol access, as well as cognitive behavioral task employed. Our aim was to query whether the nature and severity of deficits observed may be impacted by the schedule and type of alcohol administration. We furthermore examined whether there is any apparent relationship between the amount of alcohol consumed and the severity of the deficit, as well as the potential impact of abstinence length, and other factors such as age of administration, and sex of subject. Over the past five years, researchers have overwhelmingly used non-voluntary methods of intake, however deficits are still found where intake is voluntary. Magnitude of intake and type of task seem most closely related to the likelihood of producing a deficit, however even this did not follow a consistent pattern. We highlight the importance of using systematic and clear reporting styles to facilitate consistency across the literature in this regard. We hope that this analysis will provide important insights into how experimental protocols might influence findings, and how different patterns of consumption are more or less likely to produce an addiction-vulnerable cognitive phenotype in animal models.

Changes in Neuropsychological Status during the Initial Phase of Abstinence in Alcohol Use Disorder: Neurocognitive Impairment and Implications for Clinical Care

BACKGROUND

Neuropsychological deficits are common in individuals with alcohol use disorder (AUD) and impact daily functioning and AUD treatment outcomes. Longitudinal studies demonstrate that extended abstinence improves neuropsychological functioning. The effects of short-term abstinence are less clear.

OBJECTIVES

This study examined changes in neuropsychological functioning after acute detoxification over a 10-day period at the beginning of residential AUD treatment. Notably, this study evaluated cognitive functioning according to diagnostic classifications for neurocognitive disorder according to DSM-5.

METHODS

Using a within-subjects design, neuropsychological functioning of participants (N = 28) undergoing a 14-day residential AUD treatment program was assessed at two time points over 10 days (i.e., treatment entry, prior to treatment discharge). Tests of immediate memory, visuospatial abilities, attention, language abilities, delayed memory, and executive functioning were administered.

RESULTS

After completing acute detoxification, almost all participants (93%) were clinically impaired in at least one of the five cognitive domains at residential treatment entry, with one third of the sample impaired on ≥3 domains. Ten days later, 71% remained clinically impaired in at least one of five cognitive domains, with 29% of the sample impaired on ≥3 domains. Significant improvement over the 10-day period was observed for immediate memory, visuospatial abilities, and overall cognitive functioning. Clinical significance of these changes is also reported. Conclusions/Importance: The results from this study help to characterize cognitive functioning in terms of neurocognitive impairment. A brief period of abstinence begins to ameliorate neuropsychological deficits, but many individuals remain cognitively impaired throughout treatment. Implications for treatment are discussed.

Persistent negative effects of alcohol drinking on aspects of novelty-directed behavior in male rhesus macaques

Humans with histories of prolonged heavy alcohol use exhibit poorer performance on cognitive tasks associated with problem solving, short-term memory, and visuospatial reasoning, even following the cessation of drinking, when compared with healthy controls. It is unclear, however, whether the cognitive problems are a consequence of alcohol exposure or a contributing factor to alcohol-use disorders. Here, we examined the relationship between performance on a novel object recognition (NOR) task and total alcohol consumption (TAC) in adult male rhesus macaques (n = 12; ETH group; trained to self-administer alcohol). NOR performance in this group was assessed prior to induction of alcohol drinking ("pre") and, again, after a 1-year abstinence period ("post") and was compared to the performance of a second group (n = 6; Control group), which was alcohol-naïve. In the NOR task, difficulty was manipulated across three phases by varying specific object features and/or by varying duration of access to objects. For each monkey, we measured aspects of novelty-related behavior including novelty detection, novelty reactivity, and perseverative behavior. TAC during induction and a "free" access period in which the monkey could choose between water and a 4% w/v ethanol solution also was determined. We found that performance deficits in the NOR task were a consequence of high total alcohol intake instead of a predictor of subsequent high intake. Poor NOR performance in drinkers with the highest intakes was characterized by increased perseverative behavior rather than an inability to detect or react to novelty. Finally, the observed deficits are long-lasting - persisting even after a year of abstinence. Given the prevalent and persistent nature of alcohol-induced cognitive deficits in patients in treatment settings, understanding the nature of the deficit and its neural basis could ultimately offer novel treatment approaches based on the reversal of alcohol-induced impairment.

Prevalence of cognitive impairment among Hungarian patients with relapsing-remitting multiple sclerosis and clinically isolated syndrome

BACKGROUND

Cognitive impairment (CI) is a frequent symptom of multiple sclerosis (MS); its prevalence is reported to be 43-70%. It is one of the most important determinants of MS patients' quality of life, as it is one of the main factors for MS patients becoming unemployed.

AIM

We aimed to determine the prevalence of CI among the relapsing-remitting MS (RRMS) and clinically isolated syndrome (CIS) patients in Hungary, to evaluate the predicting factors of CI and to assess the differences between sexes and patients with different educational levels.

PATIENTS AND METHODS

Five-hundred and fifty-three CIS and RRMS patients were enrolled to our study from three Hungarian MS centers. Age at screening, age at disease onset, disease duration, EDSS score, sex and educational levels were analyzed as socio-demographic factors. The BICAMS battery was used to assess their cognitive state, the BDI-II battery to assess depression. For statistical analysis, we utilized logistical regression, and used Fisher exact tests, chi-square tests and one-way ANOVA.

RESULTS

The mean age of our patients was 44.93 ± 11.69 years, mean age at disease onset was 31.95 ± 10.01 years, the mean disease duration was 13.05 ± 8.05 years and the median EDSS score 2.0 (Range: 6.5, IQR:2.0) points. Three-hundred and sixteen (57.1%) patients had CI. Sex, educational level and EDSS score proved to be significant predictors of CI (OR: 2.71, p < 0.001; OR: 1.94, p = 0.023; OR: 0.47, p = 0.003 respectively). CI was significantly (p < 0.001) more frequent among men (70.1%) than women (52.0%). We found, that educational level and EDSS score were only a significant predicting factor among women. Thus, the prevalence of CI among women with college or university degree was significantly (p < 0.001) less common (39.4%) than women with 12-15 years of education (57.4%) and women without a high school degree (66.7%). Also, we found that among women with higher EDSS score than 2 points, the prevalence of CI is 69.9% as compared to women with EDSS score between 0 and 2 points, where the prevalence is 42.8% (p < 0.001). No such differences were observed among man.

DISCUSSION

Our prevalence data is similar to those reported in the literature (43-70%), and almost identical to the one assessment using the BICAMS battery. We found that men are more vulnerable to CI than women in MS, as was reported recently. We are the first to report however, that higher educational level and lower EDSS scores are only associated with better cognitive performance in women.

Executive Attention Impairment in Adolescents With Major Depressive Disorder

Neural network models that guide neuropsychological assessment practices are increasingly used to explicate depression, though a paucity of work has focused on regulatory systems that are under development in adolescence. The purpose of this study was to evaluate subsystems of attention related to executive functioning including alerting, orienting, and executive attention networks, as well as sustained attention with varying working memory load, in a sample of depressed and well adolescents. Neuropsychological functioning in 99 adolescents diagnosed with major depressive disorder (MDD) and 63 adolescent healthy controls (M = 16.6 years old) was assessed on the Attention Network Test (ANT) and the Continuous Performance Test, Identical Pairs. Adolescents with MDD, particularly those who were not medicated, were slower to process conflict (slower reaction time on the Executive Attention scale of the ANT) compared to controls, particularly for those who were not undergoing psychopharmacological treatment. Tentative evidence also suggests that within the MDD group, orienting performance was more impaired in those with a history of comorbid substance use disorder, and alerting was more impaired in those with a history of a suicide attempt. Adolescents with depression showed impaired executive attention, although cognitive performance varied across subgroups of patients. These findings highlight the importance of examining neurocognitive correlates associated with features of depression and suggest an avenue for future research to help guide the development of interventions.