Investigation of impulsivity in a sample of treatment-seeking pathological gamblers: a multidimensional perspective.

Numerous studies have shown that problem gambling is characterised by lack of impulse control. However, they have often been conducted without considering the multifaceted nature of impulsivity and related psychological mechanisms. The current study aims to disentangle which impulsivity facets are altered in pathological gambling. Twenty treatment-seeking pathological gamblers (PGs) and 20 matched control participants completed a self-reported questionnaire measuring the various facets of impulsive behaviours (UPPS Impulsive Behaviour Scale), as well as two laboratory tasks assessing inhibitory control (the go-stop task) and tolerance for delayed rewards (single key impulsivity paradigm). Compared with matched controls, PGs exhibited higher urgency, lower premeditation, impairment in prepotent inhibition, and lower tolerance towards delayed rewards. Nevertheless, complementary profile analyses showed that impulsivity-related deficits found in PGs are highly heterogeneous, and that some PGs are neither impulsive in the impulsivity facets assessed nor impaired in the cognitive mechanisms measured. These findings underscore (1) the necessity to disentangle the construct of impulsivity into lower-order components and (2) that further studies should take into account, in addition to impulsivity-related mechanisms, other psychological factors potentially involved in pathological gambling.

Trait-related decision-making impairment in the three phases of bipolar disorder.

BACKGROUND: In bipolar disorder (BD), little is known about how deficits in neurocognitive functions such as decision-making are related to phase of illness. We predicted that manic, depressed, and euthymic bipolar patients (BPs) would display impaired decision-making, and we tested whether clinical characteristics could predict patients' decision-making performance. METHODS: Subjects (N = 317; age range: 18-65 years) including 167 BPs (45 manic and 32 depressed inpatients, and 90 euthymic outpatients) and 150 age-, IQ-, and gender-matched healthy control (HC) participants, were included within three university psychiatric hospitals using a cross-sectional design. The relationship between predictor variables and decision-making was assessed by one-step multivariate analysis. The main outcome measures were overall decision-making ability on the Iowa Gambling Task (IGT) and an index of sensitivity to punishment frequency. RESULTS: Manic, depressed, and euthymic BPs selected significantly more cards from the risky decks than HCs (p < .001, p < .01, and p < .05, respectively), with no significant differences between the three BD groups. However, like HCs, BPs preferred decks that yielded infrequent penalties over those yielding frequent penalties. In multivariate analysis, decision-making impairment was significantly (p < .001) predicted by low level of education, high depressive scores, family history of BD, use of benzodiazepines, and nonuse of serotonin and norepinephrine reuptake inhibitor (SNRI) antidepressants. CONCLUSIONS: BPs have a trait-related impairment in decision-making that does not vary across illness phase. However, some subtle differences between the BD groups in the individual deck analyses may point to subtle state influences on reinforcement mechanisms, in addition to a more fundamental trait impairment in risk-sensitive decision making.

Differential responses to emotional interference in paranoid schizophrenia and bipolar mania.

BACKGROUND: Studies on emotional biases towards threat-related stimuli in schizophrenia and bipolar disorder have provided, so far, inconsistent results. The aim of the present study was to investigate emotional interference in acute schizophrenic and manic patients and its clinical correlates by using a card version of the Emotional Stroop Task designed with neutral, paranoid, depressive and manic words. METHODS: Thirty paranoid schizophrenia patients, 30 manic patients and 60 healthy controls were compared on the Emotional Stroop Test. Response times (RT) were collected for each card. Interference indices were calculated by subtracting the RT for the neutral card from the RT for the depressive, paranoid and manic cards. RESULTS: The schizophrenic and manic patient groups showed an increased interference effect when the emotional valence was relating to the disorder-specific psychopathology. In addition, the paranoid interference index correlated with positive symptoms in schizophrenic patients. By contrast, no correlation was evidenced between interference indices and mood symptoms in the manic group. CONCLUSIONS: Among schizophrenic patients, paranoid interference might be a state-related emotional abnormality associated with persecutory delusions. In mania, we suggest that emotional biases towards depressive as well as manic information might be trait features of the emotional hyperreactivity involved in the vulnerability to bipolar disorder.

Remission from mania is associated with a decrease in amygdala activation during motor response inhibition.

OBJECTIVES: Neuroimaging studies of bipolar disorder (BD) have provided evidence of brain functional abnormalities during both the states of mania and remission. However, the differences in brain function between these two states are still poorly known. In the current study, we aimed to use a longitudinal design to examine the functional changes associated with symptomatic remission from mania within the brain network underlying motor response inhibition. METHODS: Using event-related functional magnetic resonance imaging (fMRI), 10 BD patients and 10 healthy subjects were imaged twice while performing a Go/NoGo task. Patients were in a manic state when they underwent the first scan and fully remitted during the second scan. A mixed-effect ANOVA was used to identify brain regions showing differences in activation change over time between the two groups. RESULTS: The left amygdala was the only brain region to show a time-dependent change in activation that was significantly different between BD patients and healthy subjects. Further analyses revealed that this difference arose from the patient group, in which amygdala activation was decreased between mania and subsequent remission. CONCLUSIONS: This finding suggests that a decrease in left amygdala responsiveness is a critical phenomenon associated with remission from mania. It emphasizes the relevance of longitudinal approaches for identifying neurofunctional modifications associated with mood changes in BD.

Reduced brain activation in euthymic bipolar patients during response inhibition: an event-related fMRI study.

Deficits in inhibitory control have been reported in euthymic bipolar disorder patients. To date, data on the neuroanatomical correlates of these deficits are exclusively related to cognitive inhibition. This study aimed to examine the neural substrates of motor inhibitory control in euthymic bipolar patients. Groups of 20 patients with euthymic bipolar disorder and 20 demographically matched healthy subjects underwent event-related functional magnetic resonance imaging while performing a Go-NoGo task. Between-group differences in brain activation associated with motor response inhibition were assessed by using random-effects analyses. Although euthymic bipolar patients and healthy subjects performed similarly on the Go-NoGo task, they showed different patterns of brain activation associated with response inhibition. Specifically, patients exhibited significantly decreased activation in the left frontopolar cortex and bilateral dorsal amygdala compared with healthy subjects. There were no brain regions that were significantly more activated in patients than in healthy subjects. The findings suggest that euthymic bipolar patients have deficits in their ability to engage the left frontopolar cortex and bilateral dorsal amygdala during response inhibition. Further research should ascertain the role that such deficits may play in the emergence of impulsive behaviors that characterize bipolar disorder.

Bilateral decrease in ventrolateral prefrontal cortex activation during motor response inhibition in mania.

Mania has been frequently associated with impaired inhibitory control. The present study aimed to identify brain functional abnormalities specifically related to motor response inhibition in mania by using event-related fMRI in combination with a Go/NoGo task designed to control for extraneous cognitive processes involved in task performance. Sixteen manic patients and 16 healthy subjects, group-matched for age and sex, were imaged while performing a warned equiprobable Go/NoGo task during event-related fMRI. Between-group differences in brain activation associated with motor response inhibition were assessed using analyses of covariance. Although no significant between-group differences in task performance accuracy were observed, patients showed significantly longer response times on Go trials. After controlling for covariates, the only brain region that differentiated the two groups during motor response inhibition was the ventrolateral prefrontal cortex (VLPFC), where activation was significantly decreased in both the right and left hemispheres in manic patients. Our data suggest that response inhibition in mania is associated with a lack of engagement of the bilateral VLPFC, which is known to play a primary role in the suppression of irrelevant responses. This result might give clues to understanding the pathophysiology of disinhibition and impulsivity that characterize mania.

Lack of insight may predict impaired decision making in manic patients.

OBJECTIVES: The tendency to engage in risky behaviours is a core feature of the manic episodes of bipolar disorder. The aim of this study was to establish whether this characteristic can be quantified with a laboratory measure of decision making [the Iowa Gambling Task (IGT)] and to determine clinical correlates of the IGT performance in mania. METHODS: Inpatients with acute mania (n = 45) and healthy volunteers (n = 45) were assessed on the IGT. Affective symptomatology was assessed with the Young Mania Rating Scale and Hamilton Depression Rating Scale, and item scores were subjected to factor analysis. Multivariate regression was used to assess clinical predictors of impaired decision making in the manic patients. RESULTS: On the IGT, manic patients selected more cards from the risky decks than healthy controls, and showed little capacity to learn from incurred losses. In a multivariate analysis, impaired decision making ability in the manic patients was significantly predicted by a symptom factor associated with lack of insight. CONCLUSIONS: Manic patients clearly show defects in decision making, which are strongly related to their lack of insight. Neural circuitry supporting effective decision making, including the ventromedial prefrontal cortex and somatosensory cortex, may be implicated in the pathophysiology of acute mania.

[Selecting material to develop an emotional Stroop test adapted to schizophrenia and bipolar disorders]. / Sélection du matériel pour l'élaboration d'un test de stroop émotionnel adapté aux troubles schizophréniques et bipolaires.

OBJECTIVE: The emotional Stroop test evaluates the influence of the emotional valence of stimuli on cognitive inhibition processes. In subjects with psychiatric disorders, interference increases in this test when valence refers to their specific psychopathology. This study aims to develop a version of the emotional Stroop test adapted to paranoid schizophrenia and bipolar disorder. METHOD: The emotional valence and the number of times patients used 200 words related to schizophrenia and bipolar disorder psychopathology were assessed by 25 clinicians; then a principal component analysis was performed with an ascending hierarchical classification. RESULTS: Words are distributed according to 2 factorial dimensions, emotionality and tonality, into 4 valence classifications: depressive, paranoid, manic, and neutral words. There were no differences in the lexical frequency of the words chosen to develop the test. CONCLUSIONS: The statistical validation of the emotional valence of words allows for the development of an emotional Stroop test adapted to exploring emotional bias in paranoid schizophrenia and bipolar disorder.

Blunted activation in right ventrolateral prefrontal cortex during motor response inhibition in schizophrenia.

OBJECTIVES: Previous functional magnetic resonance imaging (fMRI) studies have reported abnormal brain activation in individuals with schizophrenia during performance of motor inhibition tasks. We aimed to clarify brain functional abnormalities related to motor response inhibition in schizophrenia by using event-related fMRI in combination with a Go-NoGo task designed to control for non-inhibitory cognitive processes involved in task performance. METHOD: We studied 21 schizophrenic patients and 21 healthy subjects, group-matched for age, sex, and performance accuracy on a Go-NoGo task during event-related fMRI. The task was designed so that Go and NoGo events were equally probable. Between-group activation differences were assessed using ANCOVAs with response time and IQ as covariates of non-interest. RESULTS: Compared to healthy subjects, schizophrenic patients exhibited a significant decrease in activation during motor response inhibition in the right ventrolateral prefrontal cortex (VLPFC) only. There were no areas of increased brain activation in patients compared to healthy subjects. CONCLUSIONS: Schizophrenic patients demonstrate a blunted activation in the right VLPFC, a region known to play a critical role in motor response inhibition. Further research should ascertain the contribution of the VLPFC dysfunction to the impulsive behavior observed in schizophrenia.