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Adolescence and early adulthood are crucial periods of neurodevelopment characterised by functional, structural, and cognitive maturation, which helps prepare young people for adulthood. This systematic review of longitudinal studies aims to delineate neural predictors from neural consequences of cannabis and illicit substance use, as well as investigate the potential for the developing brain (at ages 10-25 years) to recover after damage. Five databases were searched to yield a total of 38 eligible studies, with some assessing multiple outcome techniques, including 22 neuroimaging, two neurophysiological, and 22 neuropsychological findings. High-quality evidence suggested that delayed or irregular neurodevelopment in executive functioning, particularly emotional perception, might predispose young people to higher frequency substance use. There was evidence of functional, structural, and cognitive deficits proceeding substance use, with harm potentially dependent on the frequency of use and recovery potentially dependent on the duration of use. Identifying aberrant neurodevelopment in young people is crucial for preventing substance use-related harm., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: The dorsal anterior cingulate cortex (dACC) and its neurocircuits are central in impulsivity, and maladaptive dACC activity has been implicated in psychological disorders characterized by high trait impulsivity. High-Definition transcranial Direct Current Stimulation (HD-tDCS) is a non-invasive neuromodulation tool that, with certain electrode configurations, can be optimized for targeting deeper subcorticalbrainstructures, such as the dACC., Objectives: Using behavioural and electrophysiological measures we investigated whether HD-tDCS targeting the dACC could modulate two key components of impulsivity, inhibitory control and error processing., Methods: Twenty-three healthy adults with high trait impulsivity participated in two experimental sessions. Participants received active or sham HD-tDCS in counterbalanced order with a wash-out period of at least 3 days, as part of a single-blind, cross-over design. EEG was recorded during the Go-NoGo task before, directly after, and 30 min after HD-tDCS., Results: HD-tDCS targeting the dACC did not affect inhibitory control performance on the Go-NoGo task, but there was evidence for a delayed change in underlying neurophysiological components of motor inhibition (NoGo P3) and error processing (error related negativity; ERN) after one session of HD-tDCS., Conclusion: HD-tDCS has potential to modulate underlying neurophysiological components of impulsivity. Future studies should further explore to what degree the dACC was affected and whether multi-session HD-tDCS has the capacity to also induce behavioural changes, particularly in clinical samples characterized by high trait impulsivity., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Objectives: Neurocognitive processes are key drivers of addictive and compulsive disorders. The current study examined whether reward-related attentional capture and cognitive inflexibility are associated with impulsive and/or compulsive personality traits, and whether these cognitive characteristics interact to predict greater compulsivity-related problems across obsessive-compulsive and drinking behaviors., Methods: One-hundred and seventy-three participants (mean age = 34.5 years, S.D = 8.4, 42% female) completed an online visual search task to measure reward-related attentional capture and its persistence following reversal of stimulus-reward contingencies. Participants also completed questionnaires to assess trait impulsivity, compulsivity, alcohol use, and obsessive-compulsive behaviors., Results: Greater reward-related attentional capture was associated with trait compulsivity, over and above all impulsivity dimensions, while greater cognitive inflexibility was associated with higher negative urgency (distress-elicited impulsivity). Reward-related attentional capture and cognitive inflexibility interacted to predict greater compulsivity-related problems among participants who reported obsessive-compulsive behaviors in the past month (n = 57) as well as current drinkers (n = 88). Follow-up analyses showed that, for OCD behaviors, this interaction was driven by an association between higher reward-related attentional capture and more problematic behaviors among cognitively inflexible participants only. For drinking, the same pattern was seen, albeit at trend level., Limitations: This study includes a non-clinical, online sample and is cross-sectional, thus its findings need to be interpreted with these limitations in mind., Conclusions: Reward-related attentional capture and cognitive flexibility are related to trait compulsivity and impulsivity (negative urgency) respectively, and interact to determine more problematic behaviors., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Kratom or Mitragyna speciosa (Korth.) is a medicinal plant of Southeast Asia. As a result of its opioid-like effects, it remains unknown whether consumption of kratom tea is associated with impaired cognitive function. We assessed the cognitive function of 70 regular kratom users and 25 control participants using the Cambridge Neuropsychological Test Automated Battery. Participants performed six neuropsychological tasks that assessed motor, learning and memory, attention and executive function. Relative to control participants, higher consumption (>3 glasses daily or mitragynine doses between 72.5 mg and 74.9 mg) of kratom tea was selectively associated with impaired performance on the Paired Associates Learning task, reflecting deficits in visual episodic memory and new learning. Overall, the performance of kratom users compared to control participants, and the performance of high (>3 glasses per day) as well as low (≤3 glasses per day) kratom using groups, were comparable on all neuropsychological domains. Higher intake of kratom juice (>3 glasses daily) did not appear to impair motor, memory, attention or executive function of regular kratom users.

Cannabis use has been associated with impaired cognition during acute intoxication as well as in the unintoxicated state in long-term users. However, the evidence has been mixed and contested, and no systematic reviews of the literature on neuropsychological task-based measures of cognition have been conducted in an attempt to synthesize the findings. We systematically review the empirical research published in the past decade (from January 2004 to February 2015) on acute and chronic effects of cannabis and cannabinoids and on persistence or recovery after abstinence. We summarize the findings into the major categories of the cognitive domains investigated, considering sample characteristics and associations with various cannabis use parameters. Verbal learning and memory and attention are most consistently impaired by acute and chronic exposure to cannabis. Psychomotor function is most affected during acute intoxication, with some evidence for persistence in chronic users and after cessation of use. Impaired verbal memory, attention, and some executive functions may persist after prolonged abstinence, but persistence or recovery across all cognitive domains remains underresearched. Associations between poorer performance and a range of cannabis use parameters, including a younger age of onset, are frequently reported. Little further evidence has emerged for the development of tolerance to the acutely impairing effects of cannabis. Evidence for potential protection from harmful effects by cannabidiol continues to increase but is not definitive. In light of increasing trends toward legalization of cannabis, the knowledge gained from this body of research needs to be incorporated into strategies to minimize harm., (Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Cognitive control (CC) and working memory (WM) are concurrently necessary for adaptive human behavior. These processes are thought to rely on similar neural mechanisms, yet little is known of the potential competitive or cooperative brain dynamics that support their concurrent engagement during complex behavioral tasks. Here, statistical interactions (synergy/competition) and dependencies (correlations) in brain function related to CC and WM were measured using functional magnetic resonance imaging. Twenty-five healthy adults performed a novel factorial cognitive paradigm, in which a 2-back verbal WM task was combined with the multisource interference task. Overlapping main effects in neural activation were evident in all regions of the "cognitive control network," together with robust behavioral main effects. However, no significant behavioral or cortical interaction effects were apparent. Conversely, robust positive correlations between the 2 main effects were evident within many components of the network. The results offer robust evidence that the neural representations of WM and CC are statistically dependent, but do not compete. These findings support the notion that CC and WM demands may be dynamically and flexibly encoded within a common brain network to support the efficient production of adaptive behavior across diverse task contexts., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

This study examined whether development of two forms of cognitive control (proactive and reactive) between early and midadolescence was associated with the onset of major depressive disorder (MDD) during the same period and if it prospectively predicted MDD onset between mid- and late adolescence. Adolescents (N = 165) completed 3 waves of assessments, at 12 (T1), 16 (T2), and 18 (T3) years of age. Diagnostic interviews were conducted at each time point to identify three groups of adolescents: "early MDD," those who developed MDD between early (T1) and mid- (T2) adolescence (n = 23); "late MDD," those who developed MDD between mid- (T2) and late (T3) adolescence (n = 20); and "controls," those who did not develop MDD (n = 122). A modified Stroop task was completed at T1 and T2 to examine development of proactive and reactive cognitive control. Adolescents with early MDD exhibited significant declines in reactive control, as well as a trend level decline for proactive control, during this period compared to controls. No significant differences in reactive or proactive control were identified in adolescents with late MDD compared to controls, but they did exhibit significant improvements in proactive control compared to those with early MDD. These findings suggest that normative maturation of reactive, and possibly proactive, cognitive control abilities are impaired in adolescents who develop MDD between early and midadolescence. This has implications for understanding the mechanisms underlying certain forms of behavioral dysregulation that are commonly seen in MDD.

Background: Inhalant users have multiple comorbid issues (e.g., polydrug use) that complicate identifying inhalant-specific cognitive deficits., Objectives: The aim of the present study was to use signal detection theory to identify inhalant-specific differences in executive control., Methods: We examined three well-matched groups: 19 inhalant users, 19 cannabis users, and 19 controls using Stroop and Go/No-Go tasks., Results: Inhalant users demonstrated significantly lower d-prime scores relative to controls, but not cannabis users, on both tasks, suggesting possible executive deficits relative to controls. CONCLUSIONS/IMPORTANCE: The results of this study raise questions regarding inhalant toxicity and the vulnerability of the adolescent brain to drugs of abuse.

Adolescence is a time when the ability to engage cognitive control is linked to crucial life outcomes. Despite a historical focus on prefrontal cortex functioning, recent evidence suggests that differences between individuals may relate to interactions between distributed brain regions that collectively form a cognitive control network (CCN). Other research points to a spatially distinct and functionally antagonistic system--the default-mode network (DMN)--which typically deactivates during performance of control tasks. This literature implies that individual differences in cognitive control are determined either by activation or functional connectivity of CCN regions, deactivation or functional connectivity of DMN regions, or some combination of both. We tested between these possibilities using a multilevel fMRI characterization of CCN and DMN dynamics, measured during performance of a cognitive control task and during a task-free resting state, in 73 human adolescents. Better cognitive control performance was associated with (1) reduced activation of CCN regions, but not deactivation of the DMN; (2) variations in task-related, but not resting-state, functional connectivity within a distributed network involving both the CCN and DMN; (3) functional segregation of core elements of these two systems; and (4) task-dependent functional integration of a set of peripheral nodes into either one network or the other in response to prevailing stimulus conditions. These results indicate that individual differences in adolescent cognitive control are not solely attributable to the functioning of any single region or network, but are instead dependent on a dynamic and context-dependent interplay between the CCN and DMN., (Copyright © 2014 the authors 0270-6474/14/3414096-13$15.00/0.)

Maturation of cognitive control abilities has been attributed to the protracted structural maturation of underlying neural correlates during adolescence. This study examined the relationship between development of two forms of cognitive control (proactive and reactive control) and structural maturation of the ACC, dorsolateral pFC, and ventrolateral pFC (vlPFC) between early and mid adolescence using a longitudinal design. Adolescents (n = 92) underwent baseline assessments when they were 12 years old and follow-up assessments approximately 4 years later. At each assessment, structural MRI scans were acquired, and a modified Stroop task was performed. Results showed longitudinal improvements in reactive control between early and mid adolescence. Furthermore, magnitude of the improvement in proactive control was associated with reduced thinning of the right vlPFC across the sample, whereas the magnitude of the improvements in reactive control was associated with reduced thinning of the left ACC in men alone. These findings suggest that individual differences in the maturation of ACC and vlPFC underlie the development of two distinct forms of cognitive control between early and mid adolescence as well as highlight sex differences in this relationship.

The long-term effect of regular cannabis use on brain function underlying cognitive control remains equivocal. Cognitive control abilities are thought to have a major role in everyday functioning, and their dysfunction has been implicated in the maintenance of maladaptive drug-taking patterns. In this study, the Multi-Source Interference Task was employed alongside functional magnetic resonance imaging and psychophysiological interaction methods to investigate functional interactions between brain regions underlying cognitive control. Current cannabis users with a history of greater than 10 years of daily or near-daily cannabis smoking (n=21) were compared with age, gender, and IQ-matched non-using controls (n=21). No differences in behavioral performance or magnitude of task-related brain activations were evident between the groups. However, greater connectivity between the prefrontal cortex and the occipitoparietal cortex was evident in cannabis users, as compared with controls, as cognitive control demands increased. The magnitude of this connectivity was positively associated with age of onset and lifetime exposure to cannabis. These findings suggest that brain regions responsible for coordinating behavioral control have an increased influence on the direction and switching of attention in cannabis users, and that these changes may have a compensatory role in mitigating cannabis-related impairments in cognitive control or perceptual processes.

Objectives: Neuroimaging studies have consistently implicated alterations of the basal ganglia and orbitofrontal cortex in the pathophysiology of OCD, however, recent work also emphasizes more diffuse patterns of brain alteration as occurring in this disorder. The goal of this study was to extend such observations by investigating large-scale brain functional network correlates of cognitive-control performance in OCD patients., Experimental Design: We combined fMRI with a validated task of cognitive control and a multivariate statistical method to assess multiple functional networks encompassing broad task-relevant cortical regions in OCD patients and matched controls. Functional networks of interest were targeted a priori and the groups were compared in terms of the spatiotemporal profile of network responses (functional connectivity) during the task performance in a data-driven manner., Principal Observations: Task performance was equivalent in both groups and each distinct network demonstrated strong overlap in its general response during task. However, significant differences in functional connectivity were also observed between groups that appeared driven by specific phases of task performance. Such differences were most pronounced during rest-task transitions and mainly involved dorsal anterior cingulate and insular cortices within the paralimbic network. Relative heightened functional connectivity of insula in patients during task correlated with a measure of patients' state anxiety., Conclusions: Our findings provide a novel functional imaging characterization of brain network alterations associated with cognitive-control in OCD. Additionally, these findings raise questions about the role of patients' arousal states on the performance of cognitive imaging tasks that are otherwise assumed to be emotionally neutral., (Copyright © 2011 Wiley-Liss, Inc.)

Objective: Inhibitory control is associated with temperament and intelligence, which together form an essential component of the ability to adaptively regulate behavior. Impairments in inhibitory control have been linked with a host of common and debilitating conditions, often in a sex-dependent manner. However, sex differences in inhibitory control are often not expressed experimentally during task performance. Here, we sought to examine how sex, temperament, and intelligence are related to different aspects of inhibitory control., Method: We recruited a large sample of early adolescents (n = 153; mean age 12.6 years) to comprehensively investigate the relationship between sex, self-reported and parent-reported temperamental effortful control, and intelligence with different aspects of inhibitory control--namely, strategic (or proactive) control and evaluative (or reactive) control, assessed using a modified Stroop task., Results: Compared with males, females were more efficient in their use of strategic control to reduce the magnitude of response conflict. There was no sex difference in evaluative control. Further, whereas high intelligence was associated with fewer errors for both males and females, effortful control was associated with performance accuracy only in females., Conclusions: These findings highlight sex differences in the relationship of inhibitory control to individual differences in temperamental effortful control in early adolescents and reinforce the generalized positive effects of intelligence.

Cannabis use is highly prevalent among people with schizophrenia, and coupled with impaired cognition, is thought to heighten the risk of illness onset. However, while heavy cannabis use has been associated with cognitive deficits in long-term users, studies among patients with schizophrenia have been contradictory. This article consists of 2 studies. In Study I, a meta-analysis of 10 studies comprising 572 patients with established schizophrenia (with and without comorbid cannabis use) was conducted. Patients with a history of cannabis use were found to have superior neuropsychological functioning. This finding was largely driven by studies that included patients with a lifetime history of cannabis use rather than current or recent use. In Study II, we examined the neuropsychological performance of 85 patients with first-episode psychosis (FEP) and 43 healthy nonusing controls. Relative to controls, FEP patients with a history of cannabis use (FEP + CANN; n = 59) displayed only selective neuropsychological impairments while those without a history (FEP - CANN; n = 26) displayed generalized deficits. When directly compared, FEP + CANN patients performed better on tests of visual memory, working memory, and executive functioning. Patients with early onset cannabis use had less neuropsychological impairment than patients with later onset use. Together, these findings suggest that patients with schizophrenia or FEP with a history of cannabis use have superior neuropsychological functioning compared with nonusing patients. This association between better cognitive performance and cannabis use in schizophrenia may be driven by a subgroup of "neurocognitively less impaired" patients, who only developed psychosis after a relatively early initiation into cannabis use.

Introduction and Aims: Inhalants are frequently among the first drugs abused by adolescents; however, little is known about how chronic inhalant abuse affects cognition (e.g. executive functioning). Several studies have examined cognitive deficits among inhalant users; however, no study has thoroughly addressed the confounding issues frequently associated with inhalant users (e.g. polysubstance use). The aim of the current study was to examine possible deficits in cognitive control among young, regular inhalant users and explore the relationship between inhalant use and executive functioning., Design and Methods: Three groups (n = 19) of young people (aged 14-24) were recruited: an inhalant-using group, a drug-using control group and a community control group. The inhalant and drug-using controls were matched on demographic, clinical and substance use measures. All three groups were matched on age, sex and education. Cognitive control was assessed using Stroop and Go/No-Go tasks., Results: There were no significant differences in performance between the groups on any measure. However, three measures (incongruent reaction times and congruent errors for the Stroop and omission errors for the Go/No-Go) were significantly correlated with inhalant use measures, suggesting inhalant use was associated with poorer performance., Discussion and Conclusions: The lack of significant differences between the groups is surprising; however, it raises important questions regarding cognitive deficits among chronic inhalant users. Further longitudinal studies using well-matched control participants are required to delineate the nature and timing of cognitive and neurobiological pathology among adolescent inhalant users., (© 2010 Australasian Professional Society on Alcohol and other Drugs.)

Objective: Inhalant use is a common form of drug misuse among young adolescents. However, very little is known about how chronic inhalant misuse affects cognition. Several studies have examined cognitive deficits among inhalant users, but no study has thoroughly addressed the confounding issues frequently associated with inhalant users (e.g., polysubstance use). The aim of the current study was to examine possible deficits in memory, learning, and executive components of memory (interference susceptibility) among young, regular inhalant users relative to a statistically equivalent drug-using control group (primarily cannabis users) and a community control group., Method: Three groups of 21 young people (aged 13-24 years) were recruited: an inhalant- using group, a drug-using control group, and a community control group. The inhalant and drug-using controls were matched at the group level on demographic, clinical, and substance use measures. All three groups were statistically equivalent on age, sex, and education. The Rey Auditory Verbal Learning Test was used to assess memory, learning, and interference susceptibility., Results: Community controls performed significantly better than both drug-using groups, while inhalant users were more susceptible to proactive interference relative to drug-using controls., Conclusions: Difficulty in successful proactive interference resolution demonstrated by the inhalant group may relate to inhalant-specific deficits in executive functioning. These findings raise important questions regarding the hypothesized toxicity of inhalants and of substance-specific cognitive deficits among regular adolescent substance users. Future studies should consider using more specific, experimental probes of cognitive functioning to identify potentially subtle changes among substance-using adolescents.

The structural and functional consequences of interindividual variations in cortical morphology are poorly understood. In this study, we examined the relationship between one well-characterized variation of the medial frontal lobes, variability of the paracingulate sulcus (PCS), and grey matter volume, cortical thickness, surface area, and sulcal depth of the adjacent anterior cingulate cortex (ACC) and paracingulate cortex (PaC). Seventy-seven healthy individuals were assigned to one of four groups depending on PCS incidence in both hemispheres: left-present, right-absent; left-absent, right-present; both absent; or both present. Comparing these groups on each measure yielded four primary findings: (1) The presence of a PCS was associated with increased PaC and decreased ACC grey matter volume in the hemisphere in which it was apparent, with an almost identical pattern being observed for surface area; (2) there was a more complex relationship between PCS variability and regional thickness, such that a PCS in the left hemisphere was associated with increased left PaC and right ACC thickness, with no comparable effects being observed for the presence of a right PCS; (3) the depths of all major left hemisphere sulci in the region were strongly positively correlated, whereas no such associations were apparent in the right hemisphere; and (4) a leftward asymmetry in PaC thickness was specifically associated with better performance on a test of spatial working memory ability. These results provide evidence for a complex interhemispheric relationship between sulcal variability and cortical morphometry, and indicate that such relationships may be important for understanding individual differences in cognitive abilities.

Background: The US National Institutes of Mental Health Research Domain Criteria (RDoC) seek to stimulate research into biologically validated neuropsychological dimensions across mental illness symptoms and diagnoses. The RDoC framework comprises 39 functional constructs designed to be revised and refined, with the overall goal of improving diagnostic validity and treatments. This study aimed to reach a consensus among experts in the addiction field on the 'primary' RDoC constructs most relevant to substance and behavioural addictions. Methods: Forty‐four addiction experts were recruited from Australia, Asia, Europe and the Americas. The Delphi technique was used to determine a consensus as to the degree of importance of each construct in understanding the essential dimensions underpinning addictive behaviours. Expert opinions were canvassed online over three rounds (97% completion rate), with each consecutive round offering feedback for experts to review their opinions. Results: Seven constructs were endorsed by ≥ 80% of experts as 'primary' to the understanding of addictive behaviour: five from the Positive Valence System (reward valuation, expectancy, action selection, reward learning, habit); one from the Cognitive Control System (response selection/inhibition); and one expert‐initiated construct (compulsivity). These constructs were rated to be related differentially to stages of the addiction cycle, with some linked more closely to addiction onset and others more to chronicity. Experts agreed that these neuropsychological dimensions apply across a range of addictions. Conclusions: The study offers a novel and neuropsychologically informed theoretical framework, as well as a cogent step forward to test transdiagnostic concepts in addiction research, with direct implications for assessment, diagnosis, staging of disorder, and treatment. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine cognitive functioning in people following first-episode mania relative to a demographically similar healthy control group. Methods: Forty-one patients, who had recently stabilised from a first manic episode, and twenty-one healthy controls, were compared in an extensive cognitive assessment. Results: First-episode mania participants had significantly lower Full-Scale IQ (FSIQ) relative to healthy controls; however, this finding could be driven by premorbid differences in intellectual functioning. There were no significant differences between groups in Verbal IQ (VIQ) and Performance IQ (PIQ). First-episode mania participants performed significantly poorer than healthy controls in processing speed, verbal learning and memory, working memory, and cognitive flexibility with medium-to-large effects. There were no group differences in other measures of cognition. Conclusions: Participants following first-episode mania have poorer global intelligence than healthy controls, and have cognitive difficulties in some, but not all areas of cognitive functioning. This highlights the importance of early intervention and cognitive assessment in the early course of the disorder. [ABSTRACT FROM AUTHOR]

Objectives: Cognitive deficits are apparent in the early stages of bipolar disorder; however, the timing and trajectory of cognitive functioning following a first episode of mania remains unclear. The aim of this study was to assess the trajectory of cognitive functioning in people following a first episode of mania over a 12-month period, relative to healthy controls. Method: The cohort included 61 participants who had recently stabilised from a first treated manic episode, and 21 demographically similar healthy controls. These groups were compared on changes observed over time using an extensive cognitive battery, over a 12-month follow-up period. Results: A significant group by time interaction was observed in one measure of processing speed (Trail Making Test – part A,) and immediate verbal memory (Rey Auditory Verbal Learning Test – trial 1), with an improved performance in people following a first episode of mania relative to healthy controls. On the contrary, there was a significant group by time interaction observed on another processing speed task pertaining to focussed reaction time (Go/No-Go, missed go responses), with first episode of mania participants performing significantly slower in comparison with healthy controls. Furthermore, a significant group by time interaction was observed in inhibitory effortful control (Stroop effect), in which healthy controls showed an improvement over time relative to first episode of mania participants. There were no other significant interactions of group by time related to other measures of cognition over the 12-month period. Conclusion: Our findings revealed cognitive change in processing speed, immediate memory and one measure of executive functioning over a 12-month period in first episode of mania participants relative to healthy controls. There was no evidence of change over time for all other cognitive domains. Further studies focussed on the at-risk period, subgroup analysis, and the effects of medication on the cognitive trajectory following first episode of mania are needed. [ABSTRACT FROM AUTHOR]

Abstract: Task-induced deactivations (TIDs) of midline cortical regions are readily observed in fMRI studies and may reflect elements of a ‘default-mode’ of brain function associated with self-directed mental processes at rest. In this study, we examined this TID phenomenon in schizophrenia and its relevance to patients'' symptoms, task performance and level of emotional awareness. Relative to control subjects, patients showed significantly greater TID of the rostral anterior cingulate (rAC)/medial prefrontal cortex (mPFC) and precuneus (PrC)/posterior cingulate cortex (PC). The magnitude of prefrontal TIDs was associated with patients'' task performance and emotional awareness for others. The nature of these associations suggests a complex interchange between cognitive and emotional influences on the resting-state activity of these prefrontal ‘default mode’ regions in schizophrenia. [Copyright &y& Elsevier]

Abstract: Background: It has been suggested that patients with psychotic bipolar disorder (BDP+) might have more severe cognitive deficits than non-psychotic bipolar disorder patients (BDP−). However, only a handful of studies have compared cognition between BDP+ and BDP−. Our aim was to examine cognitive deficits associated with psychosis in BD using meta-analytic methods. Methods: After a systematic literature review, we conducted a meta-analysis on studies that compared cognition in bipolar disorder (BD) patients with and without a history of psychosis. In addition the effects of clinical and demographic confounder factors were examined with meta-regression analyses. Results: There were no significant differences for gender and duration of illness between groups. Compared with BDP−, BDP+ patients had more inpatient admissions, a younger onset of illness and used antipsychotics more commonly. BDP+ patients also performed significantly worse in 4 of 6 cognitive domains (planning and reasoning, working memory, verbal memory and processing speed). There were also differences for some individual tasks (List Learning, Delayed Recall, Trail Making B, Wisconsin Card Sorting Test, Digits Backwards, Stroop Interference, Semantic Fluency) with BDP+ patients showing moderately greater impairment on these tasks (d =0.30–0.55). Conclusions: A history of psychosis is associated with greater severity of cognitive deficits in BD. However, this effect is modest, and these findings do not suggest a complete categorical distinction between BDP+ and BDP−. Psychosis in BD might reflect partly distinct neurobiological processes. [Copyright &y& Elsevier]

It has recently been suggested that cognitive impairment should be included in the diagnostic criteria of schizophrenia. One of the main arguments in support of this suggestion has been the hope that cognitive impairment can help distinguish schizophrenia from bipolar disorder (BD). However, recent evidence shows that cognitive deficits occur in BD and persist beyond euthymia. Further, mood disorders with psychotic features might be expected to manifest greater cognitive impairment, which further complicates the potential to differentiate these disorders. The goal of the current meta-analysis was to examine the magnitude and characteristics of cognitive impairments in affective psychoses (AP). A systematic search of the existing literature sourced 27 studies that met the inclusion criteria. These studies compared cognitive performances of 763 patients with AP (550 BD and 213 major depressive disorder) and 1823 healthy controls. Meta-regression and subgroup analyses were used to examine the effects of moderator variables. Meta-analyses of these studies showed that patients with AP were impaired in all 15 cognitive tasks with large effect sizes for most measures. There were no significant differences between the magnitude of impairments between the BD and major depressive disorder groups. The largest effect size was found for symbol coding, stroop task, verbal learning, and category fluency, reflecting impairments in elementary and complex aspects of attentional processing, as well as learning and memory. In general, the pattern of cognitive impairments in AP was similar to reported findings in euthymic patients with BD, but relatively more pronounced. [ABSTRACT FROM PUBLISHER]

It has recently been suggested that the diagnostic criteria of schizophrenia should include specific reference to cognitive impairments characterizing the disorder. Arguments in support of this assertion contend that such inclusion would not only serve to increase the awareness of cognitive deficits in affected patients, among both clinicians and researchers alike, but also increase the “point of rarity” between schizophrenia and mood disorders. The aim of the current article is to examine this latter assertion in light of the recent opinion piece provided by Keefe and Fenton (Keefe RSE, Fenton WS. How should DSM-V criteria for schizophrenia include cognitive impairment? Schizophr Bull. 2007;33:912–920). Through literature review, we explore the issue of whether cognitive deficits do in fact differentiate the major psychoses. The overall results of this inquiry suggest that inclusion of cognitive impairment criteria in Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-V) would not provide a major advancement in discriminating schizophrenia from bipolar disorder and affective psychoses. Therefore, while cognitive impairment should be included in DSM-V, it should not dictate diagnostic specificity—at least not until more comprehensive evidence-based reviews of the current diagnostic system have been undertaken. Based on this evidence, we consider several alternatives for the DSM-V definition of cognitive impairment in schizophrenia, including (1) the inclusion of cognitive impairment as a specifier and (2) the definition of cognitive impairment as a dimension within a hybrid categorical-dimensional system. Given the state of current evidence, these possibilities appear to represent the most parsimonious approaches to the inclusion of cognitive deficits in the diagnostic criteria of schizophrenia and, potentially, of mood disorders. [ABSTRACT FROM PUBLISHER]

The underlying neurobiology of emerging psychotic disorders is not well understood. While there is evidence from structural imaging and other studies supporting the popular notion that schizophrenia arises as a consequence of an “early neurodevelopmental” lesion, more recent findings challenge this notion. Evidence, including our own data, suggests that dynamic brain changes occur during the earliest stages of a psychotic illness, including around the time of transition to illness. In this article we review the available longitudinal and relevant cross-sectional structural neuroimaging studies focusing on both the very early neurodevelopmental markers (pre- or perinatal origin) and the later markers (late neurodevelopmental) around the period of transition to illness. Based on our review of recent findings, we suggest that the onset of psychosis is a time of active brain changes, wherein, for a proportion of individuals, (i) an early (pre- and perinatal) neurodevelopmental lesion renders the brain vulnerable to anomalous late (particularly postpubertal) neurodevelopmental processes, as indicated by evidence for accelerated loss of gray matter and aberrant connectivity particularly in prefrontal regions; and (ii) these anomalous neurodevelopmental processes interact with other causative factors associated with the onset of psychosis (e.g., substance use, stress, and dysregulation of the hypothalamic-pituitary-adrenal axis function), which together have neuroprogressive sequelae involving medial temporal and orbital prefrontal regions, as suggested by imaging studies around transition to active illness. However, the pathological processes underlying such progressive changes during “late neurodevelopment” remain unclear but may reflect anomalies of synaptic plasticity, abnormal brain maturation, the adverse effects of stress, or other environmental factors. In this context, the features of schizophrenia, including the neuropsychological deficits and behavioral manifestations, can be understood as direct effects of these multiple pathological processes at various neurodevelopmental stages, including genetic and nongenetic etiological factors. [ABSTRACT FROM PUBLISHER]

Objective: The evidence from structural imaging studies supports the notion that schizophrenia arises from an early abnormality in brain development. In this paper we review the timing of structural changes in schizophrenia and argue that schizophrenia is a neuro­developmental disorder with limited progressive brain changes occurring during the evolution and early phase of psychosis. Method: The available cross-sectional and longitudinal studies are reviewed, along with data from our own research. Results: The current literature, including our own data, suggests that structural brain changes are apparent premorbidly, consistent with a neurodevelopmental lesion. These are prominent in frontal and cingulate regions, and appear related to premorbid neuropsychological deficits in executive function. However, there appear to be additional brain changes over the transition to illness and beyond. Conclusions: We propose first, that an early neurodevelopmental insult interacts with either normal or abnormal postpubertal brain maturation to produce further (late neurodevelop­mental) brain structural and functional changes; and second, that the effect of such neurodevelopmental lesions will have different consequences for functions that normally develop early in life, such as memory, compared with functions developing later, such as executive functions. A model is presented suggesting that the structural and functional abnormalities in schizophrenia can be understood as a consequence of the neurodevelopmental stage at which brain changes occur. [ABSTRACT FROM AUTHOR]

Objective: To illustrate the need to carefully consider mental health, psychosocial and motivational factors when investigating cognitive and intellectual impairment among chronic inhalant users. Methods: Two adolescent chronic inhalant users with similar psychosocial disadvantages (eg unstable and dysfunctional families, state-based care, school absenteeism and forensic issues) and histories of comorbid drug use and mental health problems were assessed using a battery of paper and pencil and computerised neuropsychological tests. Results: Contrary to the expectations of her case manager, one participant performed within the normal range for her age in all domains of intellectual ability, while the other participant, in line with the expectations of her case manger, showed marked cognitive deficits and intellectual disability. Conclusions: The typically complex presentation of chronic inhalant users (ie disadvantaged psychosocial backgrounds, comorbid psychopathology and poor motivation/engagement) is rarely considered when investigating associated cognitive and intellectual functioning. Future research should more carefully consider the role of such factors, given the evidence suggesting that they can considerably alter (accentuate or diminish) the association between inhalant abuse and neuropsychological impairment. [ABSTRACT FROM AUTHOR]

The article focuses on effects of cannabis on human behaviour. Topics discussed include acute and long term exposure to cannabis impairs cognition, monitoring restoration of brain function and structure from current use, found increased risk of completed suicide in individuals, and examining the link between systemic inflammation and future suicide risk.

Heavy cannabis use has been frequently associated with increased rates of mental illness and cognitive impairment, particularly amongst adolescent users. However, the neurobiological processes that underlie these associations are still not well understood. In this review, we discuss the findings of studies examining the acute and chronic effects of cannabis use on the brain, with a particular focus on the impact of commencing use during adolescence. Accumulating evidence from both animal and human studies suggests that regular heavy use during this period is associated with more severe and persistent negative outcomes than use during adulthood, suggesting that the adolescent brain may be particularly vulnerable to the effects of cannabis exposure. As the endocannabinoid system plays an important role in brain development, it is plausible that prolonged use during adolescence results in a disruption in the normative neuromaturational processes that occur during this period. We identify synaptic pruning and white matter development as two processes that may be adversely impacted by cannabis exposure during adolescence. Potentially, alterations in these processes may underlie the cognitive and emotional deficits that have been associated with regular use commencing during adolescence. [ABSTRACT FROM AUTHOR]

Neurocognitive deficits have been implicated as transdiagnostic risk markers of substance use disorders. However, these have yet to be comprehensively evaluated in other, non-substance addictions. In a large, general community sample (N = 475) the present study evaluated the neurocognitive correlates of problem alcohol use and three non-substance-related addictive behaviors: addictive eating (AE), problematic pornography use (PPU), and problematic use of the internet (PUI), to identify potential shared and distinct neurocognitive correlates. A sample of Australian residents (54.4 % female M[SD] age = 32.4[11.9] years) completed a comprehensive online assessment of neurocognitive tasks tapping into eight distinct expert-endorsed domains purportedly associated with addiction. Multiple linear regressions with bootstrapping were used to examine associations among each addictive behavior of interest and neurocognition, trait impulsivity, and compulsivity, as well as key covariates. Neurocognition was differentially associated with each addictive behavior. None of the neurocognitive domains were significantly associated with problematic alcohol use or AE (p >.05), poorer performance monitoring was significantly associated with higher levels of PPU and PUI (β = −0.10, p =.049; β = −0.09, p =.028), and a preference for delayed gratification was associated with more severe PUI (β = −0.10, p =.025). Our findings have theoretical implications for how we understand non-substance addiction and suggest the need for a more nuanced approach to studying addictive behaviors that take into account the underlying neurocognitive mechanisms associated with each type of addiction. [ABSTRACT FROM AUTHOR]

It is well-established that addiction is typically associated with a distinct pattern of neurocognitive functioning with a consensus that it is typified by impaired top-down executive control and aberrant risk-reward processing. Despite a consensus that neurocognition plays an important role in characterizing and maintaining addictive disorders, there is a lack of systematic, bottom-up synthesis of quantitative evidence showing that neurocognition predicts addictive behaviors, and which neurocognitive constructs have the best predictive validity. This systematic review aimed to assess whether cognitive control and risk-reward processes as defined by the Research Domain Criteria (RDoC) predict the development and maintenance of addictive behaviors specifically, consumption, severity, and relapse. The findings from this review expose the substantial lack of evidence for neurocognition predicting addiction outcomes. However, there is evidence that suggests reward-related neurocognitive processes may be important for the detection of early risk for addiction, as well as a potentially viable target for designing novel, more effective interventions. • There is very little research on neurocognitive predictors of non-substance addiction. • Majority of our current understanding is based on alcohol use literature. • Less than half of the studies reviewed showed neurocognition significantly predicted addiction outcome. • Neurocognition may differentially predict substance-/non-substance-related outcomes. • Reward-related processes may be important for the detection of early risk for addiction and treatment response. [ABSTRACT FROM AUTHOR]

Dopaminergic medication can induce severe addictive behaviours (e.g., pathological gambling) in susceptible Parkinson's disease (PD) patients. It is still unknown which particular neurocognitive processes become exacerbated or dysfunctional in PD patients with addictive behaviours. We sought to systematically review the relevant literature to identity potential neurocognitive correlates of medication-induced addictive behaviours in PD. We framed our review around neurocognitive processes central to four dominant accounts of substance addiction: ‘aberrant learning’, ‘incentive sensitization’, ‘impulsivity to compulsivity’ and ‘impaired response inhibition and salience attribution’. Searches of the PubMed and Scopus databases were completed on June 23, 2017. To be included, studies were required to involve: (a) medicated PD patients, without a history of deep brain stimulation, with and without addictive behaviours; (b) a reward-related or decision-making task; and (c) statistical comparison of addictive and non-addictive groups’ ‘on’ medication performance on the task(s). Studies were summarised qualitatively with statistically significant ( p <.05) group differences and effect sizes (Cohen's d ) highlighted. 35 studies were included. Findings showed that the extant literature is highly heterogeneous. The domains of reward and punishment learning, reflection impulsivity and disadvantageous decision-making exemplify this. More homogeneity exists in domains in which (a) neurocognitive dysfunction is not apparent (motor control, cognitive/attentional flexibility and cognitive control) or (b) typical neurocognitive processes appear exacerbated by medication (reward motivation and choice impulsivity). Future large-scale neurocognitive studies are still required to develop our scientific understanding of addictive behaviours in PD and aid their clinical treatment and prediction. [ABSTRACT FROM AUTHOR]

The article offers information on several longitudinal studies which examined the structural magnetic resonance imaging (MRI) and neurocognitive profiles of individuals at ultra-high risk (UHR) for developing psychosis. One study observed that the grey matter of individuals at high-risk who converted to psychosis showed loss in left inferior frontal, medial temporal and inferior temporal regions. Similar changes were reported in an another study. The neuropsychological functioning of UHR patients was also assessed to examine neurocognitive processes.