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Author: Stephane Potvin (109)


Jan
2018

Methamphetamine has long been considered as a neurotoxic substance causing cognitive deficits. Recently, however, the magnitude and the clinical significance of the cognitive effects associated with methamphetamine use disorder (MUD) have been debated. To help clarify this controversy, we performed a meta-analysis of the cognitive deficits associated with MUD.

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Dec
2017

High rates of violence are found amid offenders with severe mental illnesses (SMI), substance use disorders (SUDs) and Cluster B personality disorders. Elevated rates of comorbidity lead to inconsistencies when it comes to this relationship. Furthermore, overlapping Cluster B personality traits have been associated with violence.

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Nov
2017

We investigated the influence of anger processing on cognitive control in male schizophrenia patients presenting violent behaviors. We recruited 23 patients without and 24 patients with (SCZ+V) a history of violent behaviors, as well as 22 healthy non-violent men. Participants were administered an affective (angry-neutral faces) Go/NoGo task while undergoing functional magnetic resonance imaging.

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Dec
1969

Violence is a major concern and is prevalent across several mental disorders. The use of substances has been associated with an exacerbation of psychiatric symptoms as well as with violence. Compared to other substances such as alcohol and cocaine, existing literature on the cannabis-violence relationship has been more limited, with most studies being conducted in the general population, and has shown controversial results.

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Nov
2017

Aggression is a major concern in psychiatric units even more so in emergency settings and is prevalent across many mental disorders. Since a prior history of aggression remains a crucial predictor of violence in hospitalized patients, appropriate tools assessing the history of violence are essential to implement management plans. The Life History of Aggression (LHA) is a widely-utilized instrument.

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Dec
1969

Cigarette smoking is highly prevalent in schizophrenia and is one of the main factors contributing to the significantly decreased life expectancy in this population. Schizophrenia smokers, compared to their counterparts with no comorbid psychiatric disorder, are largely unaware and indifferent to the long-term negative consequences of cigarette smoking. The objective of this study was to determine, for the first time, if these meta-cognitive deficits are associated with neuro-functional alterations in schizophrenia smokers.

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Dec
1969

This study investigated the neural correlates of psychotic-like experiences in youths during tasks involving inhibitory control, reward anticipation, and emotion processing. A secondary aim was to test whether these neurofunctional correlates of risk were predictive of psychotic symptoms 2 years later.
Functional imaging responses to three paradigms-the stop-signal, monetary incentive delay, and faces tasks-were collected in youths at age 14, as part of the IMAGEN study.

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Dec
2017

Chronic substance use can disrupt the reward function of the anterior cingulate cortex (ACC), biasing the ACC to favor goal-directed behaviors that converge on drug use. Here we used multimodal neuroimaging methods to ask whether modulating reward-related signaling in the ACC can reverse the atypical valuation of nondrug and drug rewards in abstinent smokers.
We first recorded functional magnetic resonance imaging data from 20 moderately dependent cigarette smokers (mean age = 25 years; no history of neuropsychiatric disorders), following an overnight period of abstinence, to identify regions of the left dorsal lateral prefrontal cortex associated with the anticipation of drug-related rewards (cigarette puff).

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Jan
2017

Substance use disorders (SUD) in first-episode psychosis (FEP) are highly prevalent and linked with poor outcomes. However, most longitudinal studies investigating their impacts in FEP have not reported proportions of patients who ceased SUD. Our aim was to examine the influence of SUD course on functional and symptomatic outcomes as well as service use in FEP.

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Dec
2016

Although patients suffering from major depressive disorder (MDD) often complain from painful symptoms, the relationship between experimental pain processes and depression has yet to be clearly characterized. Only recently have studies employing temporal summation (TS) paradigms offered preliminary insight into the co-occurrence of pain and depression. This study sets out to evaluate the contribution of spinal and supraspinal processes in pain sensitization in MDD using a TS paradigm.

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Jan
2017

Substance use disorders (SUDs) are significant risk factors for psychiatric relapses and hospitalizations in psychiatric populations. Unfortunately, no instrument has been validated for the screening of SUDs in psychiatric emergency settings. The Drug Abuse Screening Test (DAST) is widely used in the addiction field, but is has not been validated in that particular context.

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Jan
2017

Schizophrenia is associated with core emotional dysfunctions. At the neural level, functional neuro-imaging studies have highlighted fronto-limbic alterations during emotion processing in schizophrenia, as well as impaired connectivity between the amygdala and the prefrontal cortex. However, the direction of the impaired fronto-limbic connections remains largely unknown.

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Dec
1969

Reliable evidence shows that schizophrenia patients tend to experience negative emotions when presented with emotionally neutral stimuli. Similarly, several functional neuroimaging studies show that schizophrenia patients have increased activations in response to neutral material. However, results are heterogeneous.

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Dec
1969

Evidence suggests a 2.1-4.6 times increase in the risk of violent behavior in schizophrenia compared to the general population.

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Dec
2016

A formal meta-analysis of the use of electroconvulsive therapy (ECT) has never been conducted before in literature reviews or syntheses. Such a study would be hampered by heterogeneity and potential reporting biases. However, it would provide a single comparable measure to allow an analysis of statistical key dimensions such as trends across time and psychiatric resources available.

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Dec
1969

Several case reports have described stories of schizophrenia patients reporting no discomfort in response to several medical conditions which normally elicit pain. Comparatively, experimental studies performed on pain perception in schizophrenia have not documented hypoalgesic responses that are as frank as those reported in these clinical cases. Here, we report the case of a female patient with schizoaffective disorder, who displayed markedly reduced pain perception during an experimental heat pain paradigm.

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Dec
1969

Although fibromyalgia (FM) is associated with a deficit in inhibitory conditioned pain modulation (CPM), the discriminative power of CPM procedures is unknown. Moreover, the high intersubject heterogeneity in CPM responses in FM raises the possibility that a sizeable subgroup of these patients may experience pain facilitation during CPM, but the phenomenon has not been explicitly studied. To address these issues, 96 patients with FM and 71 healthy controls were recruited.

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May
2016

Highly prevalent in schizophrenia, tobacco smoking substantially increases the risk of cardiac-related death. Compared to the general population, tobacco smoking cessation rates are lower in schizophrenia. Unfortunately, the reasons for these low cessation rates remain poorly understood.

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Dec
1969

Craving is a core feature of tobacco use disorder as well as a significant predictor of smoking relapse. Studies have shown that appetitive smoking-related stimuli (e.g.

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Dec
1969

Background. Substance-induced psychotic disorder (SIPD) is a diagnosis constructed to distinguish substance-induced psychotic states from primary psychotic disorders. A number of studies have compared SIPD persons with primary psychotic patients, but there is little data on what differentiates substance use disorder (SUD) individuals with and without SIPD.

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Dec
2015

In view of the greater prevalence of depression and anxiety disorders in women than in men, functional magnetic resonance imaging (fMRI) studies have examined sex-differences in brain activations during emotion processing. Comparatively, sex-differences in brain connectivity received little attention, despite evidence for important fronto-limbic connections during emotion processing across sexes. Here, we investigated sex-differences in fronto-limbic connectivity during negative emotion processing.

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Oct
2015

To examine the neural correlates of emotion processing in treatment-resistant patients with schizophrenia (SCZ-TR).
Twenty-two SCZ-TR patients on clozapine, 24 schizophrenia patients on antipsychotics other than clozapine, and 39 healthy controls were scanned using functional neuroimaging while viewing positive, negative and neutral images.
Emotionally-laden images (positive and negative) elicited hyper-activations in the dorso-medial prefrontal cortex and left cerebellum in SCZ-TR patients, compared to the two other groups.

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Jul
2015

The Gyrification Index (GI) represents the degree of cortical folding and is of special interest in schizophrenia, since alterations in cortical folding indirectly reflects white matter development and axonal connectivity underneath. To the best of our knowledge, very few studies have investigated the effect of sex on GI in schizophrenia. Differences in the GI between patients with schizophrenia and healthy controls and the relation between sex, age symptoms and duration of illness with GI were investigated.

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Jul
2015

Chronic pain is a complex phenomenon resulting from biological, psychological and social factors, and the use of patient-centred care (PCC) appears to be a promising avenue for its treatment. Various methods have been used for measuring PCC in nurses and physicians (caregivers); however, methodological problems have been raised following the observation of real clinical encounters or standardized patient simulations. The development of new strategies is required.

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Mar
2016

Recent studies demonstrate that empathy-evoked brain responses include the activation of brainstem structures responsible for triggering descending pain inhibition. Unfortunately, direct evidence linking empathy for pain and descending inhibitory controls (conditioned pain modulation) is lacking. This study, therefore, aimed to determine if the observation of ourselves or a loved-one in pain could activate descending pain inhibition without exposure to a noxious stimulation; which is otherwise required.

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Mar
2015

Weight gain is a major side effect of antipsychotics (APs), which contributes to poor treatment adherence and significant morbidity. The mechanisms involved in AP-induced weight gain are incompletely understood. Recently, it has been proposed that changes in leptin, an cadipocyte-derived hormone exerting anorexigenic effects, may be involved in AP-induced weight gain.

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Dec
1969

Background Schizophrenia is well-known to be associated with a lack of insight into symptoms. Comparatively, little is known on insight into neurocognitive deficits in schizophrenia, despite the fact that these dysfunctions are undoubtedly core features of the disorder. Recently, growing interest has been paid to subjective cognition, and thus far, results have been heterogeneous.

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Dec
1969

Objectives The comorbidity between psychosis and substance use has attracted wide attention over the years, and a vast literature is now available for meta-analytic treatment. In the field, a majority of authors assume that cannabis smoking is a risk factor for psychosis, that substance abuse is highly prevalent in schizophrenia, that substance abuse worsens the prognosis of schizophrenia, and that integrated treatments have greater efficacy than treatment-as-usual for this complex population. The objective of the current article is to review the meta-analyses that have been published in the comorbidity field in order to determine if the above-mentioned assumptions are substantiated by evidence or not.

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Dec
1969

While overall more men than women smoke cigarettes, women and girls take less time to become dependent after initial use and have more difficulties quitting the habit. One of the factors contributing to these differences may be that women crave cigarettes more than men and that their desire to smoke is influenced by hormonal fluctuations across the menstrual cycle. Therefore, the purpose of the present study was twofold: (a) to examine potential sex/gender differences in functional neuroanatomy of craving and to (b) delineate neural correlates of cigarette cravings in women across their menstrual cycle.

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Dec
2014

Despite knowledge of the harmful consequences of smoking on health, tobacco users continue to smoke. Neuroimaging studies have begun to provide insight into the mechanisms underlying this response. Regions involved in executive control and affective processing/persuasion are activated when viewing the negative value of smoking, but these systems can interact in ways that promote or hinder its impact on behavior.

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Feb
2015

Cocaine use disorder is associated with cognitive deficits. However, the literature remains somewhat ambiguous with respect to which distinct cognitive functions are the most impaired in cocaine use disorder and to how duration of abstinence affects cognitive recovery. Here, we performed a meta-analysis to determine the cognitive domains impaired in cocaine abuse/dependence and the duration of abstinence necessary to achieve cognitive recovery.

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Sep
2014

In schizophrenia (SZ), a specific binding deficit in working memory (WM) has not yet been demonstrated, given that studies with various methodologies were conducted and the results obtained were heterogeneous. Thus, a meta-analysis of 10 WM studies was performed. Effect sizes were calculated for binding and control conditions.

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Mar
2015

In view of the significant cognitive deficits in schizophrenia and their impact on patients' social and occupational functioning, and considering that the influence potential influence of antipsychotic-induced extrapyramidal symptoms on cognition in schizophrenia remains poorly understood, the current study sought to identify the clinical, socio-demographic and neurologic predictors of the cognitive performance of schizophrenia patients. Eighty-two schizophrenia-spectrum (DSM-IV criteria) outpatients were recruited. Psychiatric symptoms were evaluated with the Positive And Negative Syndrome Scale and the Calgary Depression Scale for Schizophrenia.

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May
2014

The purpose of this article was to conduct a review of the types of training offered to people with schizophrenia in order to help them develop strategies to cope with or compensate for neurocognitive or sociocognitive deficits.
We conducted a search of the literature using keywords such as "schizophrenia", "training", and "cognition" with the most popular databases of peer-reviewed journals.
We reviewed 99 controlled studies in total (though nine did not have a control condition).

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Jul
2014

Drugs of abuse and psychiatric disorders: neurobiological and clinical aspects.

Prog Neuropsychopharmacol Biol Psychiatry 2014 Jul 31;52:1-3. Epub 2014 Mar 31.
Anne-Noël Samaha, Stéphane Potvin

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Apr
2014

The addictive nature of smoking is characterized by responses to cigarette stimuli that significantly impede smoking cessation efforts. Studies have shown that smokers are roused by appetitive smoking-related stimuli, and their consumption tends to be unaffected by the negative value of smoking.
Using functional magnetic resonance imaging, the goal of this study was two-fold: to examine the brain reactivity of chronic smokers when processing the negative value of smoking using aversive smoking-related cues; to further characterize this response by comparing the latter to the processing of aversive nonsmoking-related and appetitive smoking-related cues.

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Dec
2013

Evidence-based medicine suggests that schizophrenia is associated with an inflammatory syndrome, but the extent to which this syndrome is normalized by antipsychotic treatment has yet to be determined.
A systematic quantitative review of the effects of antipsychotics on peripheral cytokine levels in schizophrenia was performed, using follow-up studies providing in vivo cytokine assessments before and after treatment.
We retrieved 23 studies (total of 762 subjects) which showed that antipsychotic treatment significantly increases plasma levels of soluble interleukin-2 receptor and reduces the plasma levels of interleukin-1β and interferon-γ.

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Sep
2013

Cannabis is one of the most widely used illicit substance among users of stimulants such as cocaine and amphetamines. Interestingly, increasing recent evidence points toward the involvement of the endocannabinoid system (ECBS) in the neurobiological processes related to stimulant addiction. This article presents an up-to-date review with deep insights into the pivotal role of the ECBS in the neurobiology of stimulant addiction and the effects of its modulation on addictive behaviors.

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Dec
1969

Growing evidence suggests that cannabis abuse/dependence is paradoxically associated with better cognition in schizophrenia. Accordingly, we performed a functional magnetic resonance imaging (fMRI) study of visuospatial abilities in 14 schizophrenia patients with cannabis abuse (DD), 14 nonabusing schizophrenia patients (SCZ), and 21 healthy controls (HCs). Participants performed a mental rotation task while being scanned.

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Oct
2013

In schizophrenia cannabis abuse/dependence is associated with poor compliance and psychotic relapse. Despite this, the reasons for cannabis abuse remain elusive, but emotions may play a critical role in this comorbidity. Accordingly, we performed a functional magnetic resonance imaging study of emotional memory in schizophrenia patients with cannabis abuse (dual-diagnosis, DD).

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Dec
1969

Impulsivity has been shown to play a pivotal role in the onset, pattern of consumption, relapse and, most notably, craving of illicit and licit drugs such as cigarette smoking. The goal of this study was to examine the neurobiological influence of trait impulsivity during cue-induced cigarette craving. Thirty-one chronic smokers passively viewed appetitive smoking-related and neutral images while being scanned and reported their feelings of craving.

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Oct
2013

Multiple sclerosis (MS) is a central nervous system disorder that is associated with progressive oligodendrocyte and neuronal loss, axonal degeneration, and demyelination. Several medications that mitigate immune abnormalities reduce both the frequency of relapses and inflammation on magnetic resonance imaging, leading to improved outcomes for people with the relapsing-remitting form of MS. However, there are no treatments for the progressive forms of MS where neurons and axons continue to degenerate; here, neuroprotective therapies, or medications that rebuild myelin to confer axonal well-being, may be useful.

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Dec
2012

Ever since the characterization of schizophrenia, clinicians have noted abnormal pain sensitivity in their patients. The published literature, however, is inconsistent concerning the nature of the change reported. The objective of this study was to characterize the pain response profile of schizophrenic patients by providing both acute and prolonged (i.

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