Longitudinal Emergence of Concurrent Mental Health and Substance Use Concerns in an Ontario School-Based Sample: The Research and Action for Teens Study.

OBJECTIVES: This study characterizes patterns of mental health, substance use and their co-occurrence, and identifies developmental trajectories associated with progression from single to concurrent mental health and substance use concerns in an Ontario school-based population. It is a longitudinal extension of the Ontario Student Drug Use and Mental Health Survey, as part of the RAFT collaborative project. METHODS: In this study, an Ontario-wide survey was administered to students across three biennial waves starting in grades 7-8 (ages 12-14). We explored how developmental patterns of externalizing, internalizing and co-occurring symptoms were differentially associated with late-adolescent (ages 17-19) problematic substance use. RESULTS: On average, students exhibited early (ages 12-14) moderate risk of an internalizing and/or externalizing disorder and approached the low threshold for a diagnostic concern for substance use disorder at age 17-19. The pattern confirmed a potential pathway from early mental health concerns to later adolescent problematic substance use, with rates of co-occurrence increasing with age. Youth with early moderate-to high externalizing and co-occurring internalizing and externalizing symptomology had the highest levels of problematic substance use, with scores indicating high likelihood of a substance use disorder diagnosis. CONCLUSIONS: Given the overall pattern of progression, early identification and referral of at-risk youth, especially youth with co-occurring mental health concerns, is of critical importance. Findings support the importance of integrated and co-located mental health and substance use services for youth to more effectively serve a diverse population of youth with varying levels of need.

OBJECTIFS: La présente étude caractérise les modèles de santé mentale, l'utilisation de substances et leur cooccurrence, et identifie les trajectoires développementales associées à la progression des problèmes isolés à concurrents de santé mentale et d'utilisation de substances dans une population scolaire de l'Ontario. Il s'agit d'une extension longitudinale du Sondage sur la consommation de drogues et la santé des élèves de l'Ontario, dans le cadre d'un projet RAFT de collaboration. MÉTHODES: Dans la présente étude, un sondage a été administré à l'échelle de l'Ontario à des élèves de trois vagues biennales commençant en 7e et 8e année (de 12 à 14 ans). Nous avons exploré comment les modèles développementaux d'externalisation, d'internalisation et les symptômes co-occurrents étaient différemment associés au début tardif (de 17 à 19 ans) d'une utilisation de substances problématique. RÉSULTATS: En moyenne, les élèves montraient un risque modéré précoce (de 12 à 14 ans) d'un trouble d'internalisation et/ou d'externalisation et s'approchaient du seuil bas d'un problème diagnostique d'utilisation de substances entre 17 et 19 ans. Le modèle confirmait une trajectoire potentielle allant de problèmes précoces de santé mentale à l'apparition ultérieure d'une utilisation de substances problématique, avec des taux de cooccurrence augmentant avec l'âge. Les jeunes ayant une externalisation modérée à élevée et une symptomatologie d'internalisation et d'externalisation co-occurrentes avaient les taux les plus élevés d'utilisation de substances problématique, leurs scores indiquant une probabilité élevée d'un diagnostic de trouble d'utilisation de substances. CONCLUSIONS: Étant donné le modèle de progression général, l'identification précoce et l'aiguillage d'un jeune à risque, surtout les jeunes présentant des problèmes de santé mentale co-occurrents, sont d'une importance vitale. Les résultats appuient l'importance des services intégrés et en colocation de santé mentale et d'utilisation de substances pour les jeunes afin de servir plus efficacement une population de jeunes diversifiée dont les besoins sont de niveaux variés.

Spontaneous spatial navigation circuitry in schizophrenia spectrum disorders.

Spatial memory is core to wayfinding and everyday memory. Interestingly, individuals with schizophrenia using spatial navigation strategies (cognitive mapping) are impaired, whereas those using response-based (e.g., single-landmark) strategies show relatively intact memory performance. We observed abnormal brain communication in schizophrenia participants who used a spatial strategy during a virtual-reality navigation task, particularly between temporal and frontal brain regions. In contrast, schizophrenia participants using a response strategy recruited similar brain systems to healthy participants, but to a greater extent to support memory performance. These findings highlight that strategy use is an important consideration for understanding memory systems and navigation in schizophrenia.

Traditional test administration and proactive interference undermine visual-spatial working memory performance in schizophrenia-spectrum disorders.

Introduction Working-memory (WM) is a core cognitive deficit among individuals with Schizophrenia Spectrum Disorders (SSD). However, the underlying cognitive mechanisms of this deficit are less known. This study applies a modified version of the Corsi Block Test to investigate the role of proactive interference in visuospatial WM (VSWM) impairment in SSD. Methods Healthy and SSD participants completed a modified version of the Corsi Block Test involving both high (typical ascending set size from 4 to 7 items) and low (descending set size from 7 to 4 items) proactive interference conditions. Results The results confirmed that the SSD group performed worse overall relative to a healthy comparison group. More importantly, the SSD group demonstrated greater VSWM scores under low (Descending) versus high (Ascending) proactive interference; this pattern is opposite to that of healthy participants. Conclusions This differential pattern of performance supports that proactive interference associated with the traditional administration format contributes to VSWM impairment in SSD. Further research investigating associated neurocognitive mechanisms and the contribution of proactive interference across other domains of cognition in SSD is warranted.

Hippocampal activation and memory performance in schizophrenia depend on strategy use in a virtual maze.

Different strategies may be spontaneously adopted to solve most navigation tasks. These strategies are associated with dissociable brain systems. Here, we use brain-imaging and cognitive tasks to test the hypothesis that individuals living with Schizophrenia Spectrum Disorders (SSD) have selective impairment using a hippocampal-dependent spatial navigation strategy. Brain activation and memory performance were examined using functional magnetic resonance imaging (fMRI) during the 4-on-8 virtual maze (4/8VM) task, a human analog of the rodent radial-arm maze that is amenable to both response-based (egocentric or landmark-based) and spatial (allocentric, cognitive mapping) strategies to remember and navigate to target objects. SSD (schizophrenia and schizoaffective disorder) participants who adopted a spatial strategy performed more poorly on the 4/8VM task and had less hippocampal activation than healthy comparison participants using either strategy as well as SSD participants using a response strategy. This study highlights the importance of strategy use in relation to spatial cognitive functioning in SSD. Consistent with a selective-hippocampal dependent deficit in SSD, these results support the further development of protocols to train impaired hippocampal-dependent abilities or harness non-hippocampal dependent intact abilities.

Semantic congruence affects hippocampal response to repetition of visual associations.

Recent research has shown complementary engagement of the hippocampus and medial prefrontal cortex (mPFC) in encoding and retrieving associations based on pre-existing or experimentally-induced schemas, such that the latter supports schema-congruent information whereas the former is more engaged for incongruent or novel associations. Here, we attempted to explore some of the boundary conditions in the relative involvement of those structures in short-term memory for visual associations. The current literature is based primarily on intentional evaluation of schema-target congruence and on study-test paradigms with relatively long delays between learning and retrieval. We used a continuous recognition paradigm to investigate hippocampal and mPFC activation to first and second presentations of scene-object pairs as a function of semantic congruence between the elements (e.g., beach-seashell versus schoolyard-lamp). All items were identical at first and second presentation and the context scene, which was presented 500ms prior to the appearance of the target object, was incidental to the task which required a recognition response to the central target only. Very short lags 2-8 intervening stimuli occurred between presentations. Encoding the targets with congruent contexts was associated with increased activation in visual cortical regions at initial presentation and faster response time at repetition, but we did not find enhanced activation in mPFC relative to incongruent stimuli at either presentation. We did observe enhanced activation in the right anterior hippocampus, as well as regions in visual and lateral temporal and frontal cortical regions, for the repetition of incongruent scene-object pairs. This pattern demonstrates rapid and incidental effects of schema processing in hippocampal, but not mPFC, engagement during continuous recognition.

Spatial-memory deficit in schizophrenia spectrum disorders under viewpoint-independent demands in the virtual courtyard task.

This study builds upon our previous work indicating that impaired hippocampal-dependent forms of memory are core to schizophrenia. Using a virtual-reality courtyard task, we presented participants with schizophrenia spectrum disorders (SSD; n = 20) and a healthy community comparison group (n = 20) with objects to remember within a town square, followed by a recognition test of the location of objects from either the same viewpoint or a shifted viewpoint relative to initial presentation. The SSD group demonstrated a relative deficit under shifted- compared to same-view conditions. These findings provide further support for deficient hippocampal-dependent cognition in SSD.

Selective deficit in spatial memory strategies contrast to intact response strategies in patients with schizophrenia spectrum disorders tested in a virtual navigation task.

Spatial memory is impaired among persons with schizophrenia (SCZ). However, different strategies may be used to solve most spatial memory and navigation tasks. This study investigated the hypothesis that participants with schizophrenia-spectrum disorders (SSD) would demonstrate differential impairment during acquisition and retrieval of target locations when using a hippocampal-dependent spatial strategy, but not a response strategy, which is more associated with caudate function. Healthy control (CON) and SSD participants were tested using the 4-on-8 virtual maze (4/8VM), a virtual navigation task designed to differentiate between participants' use of spatial and response strategies. Consistent with our predictions, SSD participants demonstrated a differential deficit such that those who navigated using a spatial strategy made more errors and took longer to locate targets. In contrast, SSD participants who spontaneously used a response strategy performed as well as CON participants. The differential pattern of spatial-memory impairment in SSD provides only indirect support for underlying hippocampal dysfunction. These findings emphasize the importance of considering individual strategies when investigating SSD-related memory and navigation performance. Future cognitive intervention protocols may harness SSD participants' intact ability to navigate using a response strategy and/or train the deficient ability to navigate using a spatial strategy to improve navigation and memory abilities in participants with SSD.

Anomalous bodily-self experiences among recreational ketamine users.

INTRODUCTION: Out-of-body experiences present a unique paradigm to investigate cognitive and neural mechanisms of bodily-self processes and their disorders. Previous work on out-of-body experiences associated with sleep paralysis supported a model in which illusory movement experiences reflect disrupted bodily-self integration generating anomalous vestibular and motor sensations. Further disintegration and progression of the experience may then give rise to out-of-body feelings, which in turn may instigate out-of-body autoscopy. METHODS: The current study assesses the disintegration model through analyses of out-of-body experiences reports from an online survey of individuals reporting recreational ketamine use (n=128) and cross-validation in a sample of nonketamine polydrug users (n=64). Path analyses using intensity and frequency measures of anomalous experiences assess the fit of seven competing models. RESULTS: The disintegration model (illusory movement → out-of-body feelings → out-of-body autoscopy) emerged as the best fitting model overall and results support full mediation of the relation between illusory movement experiences and out-of-body autoscopy by out-of-body feelings. Moreover, lifetime measures of ketamine use predicted the frequency of illusory movement experiences. CONCLUSIONS: The results corroborate this structural model of out-of-body phenomena and encourage a framework for future studies into aetiological mechanisms of out-of-body experiences to include neurochemical systems.

Ketamine as a primary predictor of out-of-body experiences associated with multiple substance use.

Investigation of "out-of-body experiences" (OBEs) has implications for understanding both normal bodily-self integration and its vulnerabilities. Beyond reported associations between OBEs and specific brain regions, however, there have been few investigations of neurochemical systems relevant to OBEs. Ketamine, a drug used recreationally to achieve dissociative experiences, provides a real-world paradigm for investigating neurochemical effects. We investigate the strength of the association of OBEs and ketamine use relative to other common drugs of abuse. Self-report data (N=192) from an online survey indicate that both lifetime frequency of ketamine use and OBEs during ketamine intoxication were more strongly related to the frequency of OBEs and related phenomena than other drugs. Moreover, the apparent effects of other drugs could largely be explained by associated ketamine use. The present results, consistent with the role of NMDA receptors in OBEs, should encourage future studies of the role of neurochemical systems in OBEs.

Comparison of WAIS-III short forms for measuring index and full-scale scores.

This investigation assessed the ability of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) short forms to estimate both index and IQ scores in a large, mixed clinical sample (N = 809). More specifically, a commonly used modification of Ward's seven-subtest short form (SF7-A), a recently proposed index-based SF7-C and eight-subtest short form (SF8) were evaluated. All three SFs proved adequate for estimating verbal comprehension, perceptual organization, and full-scale intelligence within considerably less time relative to an SF11 that provides full measurement of WAIS index scores. The SF7-A provided the best combination overall in terms of psychometric performance and estimated time savings. However, SF8 best represents all four factors and allows measurement of processing speed. The SF7-C was most hampered by inclusion of the Block Design subtest in the current assessment, but may prove advantageous in future extensions to the WAIS-IV.