Functional Networks of Reward and Punishment Processing and Their Molecular Profiles Predicting the Severity of Young Adult Drinking.

Alcohol misuse is associated with altered punishment and reward processing. Here, we investigated neural network responses to reward and punishment and the molecular profiles of the connectivity features predicting alcohol use severity in young adults. We curated the Human Connectome Project data and employed connectome-based predictive modeling (CPM) to examine how functional connectivity (FC) features during wins and losses are associated with alcohol use severity, quantified by Semi-Structured Assessment for the Genetics of Alcoholism, in 981 young adults. We combined the CPM findings and the JuSpace toolbox to characterize the molecular profiles of the network connectivity features of alcohol use severity. The connectomics predicting alcohol use severity appeared specific, comprising less than 0.12% of all features, including medial frontal, motor/sensory, and cerebellum/brainstem networks during punishment processing and medial frontal, fronto-parietal, and motor/sensory networks during reward processing. Spatial correlation analyses showed that these networks were associated predominantly with serotonergic and GABAa signaling. To conclude, a distinct pattern of network connectivity predicted alcohol use severity in young adult drinkers. These "neural fingerprints" elucidate how alcohol misuse impacts the brain and provide evidence of new targets for future intervention.

Clinical and behavior characteristics of individuals who used ketamine.

This study aims to depict and compare clinical characteristics and risk behavior among groups of individuals using ketamine, polydrugs or smoking cigarette. A total of 185 drug-using participants and 49 smokers participated in this study. A cross-sectional interview was used to collect information on demographics, drug- and sex-related behaviors, HIV serostatus, lower urinary tract symptoms (LUTS), behavioral dispositions. N-back memory test was used to measure short-term memory. Result shows that 10 participants (5.41%) were HIV positive and 14 (7.57%) having LUTS. Individuals with ketamine and polydrugs use have significantly worse drug-related problem than cigarette smokers. Compared to cigarette smokers and ketamine users, individuals with polydrug users scored significantly higher on impulsivity measures. Cigarette smokers performed significantly better than the other two groups on the memory tests. A few patients had been infected with HIV and diagnosed with LUTS. Findings support that memory on short term recalls of patients with ketamine use might be impaired. Study findings warrants the necessarily of further study on influences of using ketamine.

Sex differences in the neuroanatomy of alcohol dependence: hippocampus and amygdala subregions in a sample of 966 people from the ENIGMA Addiction Working Group.

Males and females with alcohol dependence have distinct mental health and cognitive problems. Animal models of addiction postulate that the underlying neurobiological mechanisms are partially distinct, but there is little evidence of sex differences in humans with alcohol dependence as most neuroimaging studies have been conducted in males. We examined hippocampal and amygdala subregions in a large sample of 966 people from the ENIGMA Addiction Working Group. This comprised 643 people with alcohol dependence (225 females), and a comparison group of 323 people without alcohol dependence (98 females). Males with alcohol dependence had smaller volumes of the total amygdala and its basolateral nucleus than male controls, that exacerbated with alcohol dose. Alcohol dependence was also associated with smaller volumes of the hippocampus and its CA1 and subiculum subfield volumes in both males and females. In summary, hippocampal and amygdalar subregions may be sensitive to both shared and distinct mechanisms in alcohol-dependent males and females.

Traumatic Experiences and PTSD Symptoms in the Chinese Male Intrafamilial Physical Violence Perpetrators: A Comparative and Structural Equation Modeling Study.

We aimed to compare traumatic experiences among the groups of perpetrators with or without violent pedigree, and establish a structural model of posttraumatic stress disorder (PTSD) symptoms as mediators of traumatic experiences and severe intrafamilial physical violence among Chinese male perpetrators. A cross-sectional survey and a face-to-face interview were conducted to examine intimate partner violence (IPV) perpetration and violent pedigree, childhood maltreatment, other traumatic events, PTSD symptoms, and severe intrafamilial physical violence in a community sample of 229 abusive men and 303 controlled men in China. Using structural equation modeling (SEM) techniques, the scores of the questionnaires were entered into the theoretical model and calculated. Findings demonstrated that the numbers of the traumatic events in four groups were significantly different with a declining trend, and the SEM data had an adequate fit. The loadings of pathways from childhood witness domestic violence (DV) to severe physical violence (SPV) were more salience than other pathways, and the indirect effect of every pathway, except for the childhood witness DV to PTSD symptoms, on severe intrafamilial physical violence in the model was significant. The results suggest that PTSD symptoms cluster as mediator of the intergenerational transmission of SPV perpetration in Chinese abusive men. Childhood witness IPV has effects on adulthood perpetration of IPV.

Substance use, anxiety, and self-management efficacy in HIV-positive individuals: A mediation analysis.

CONTEXT: In China, the social stigma of both substance use and HIV remains major barriers. HIV+ individuals have been demonstrated to have higher psychosocial distress in the literature. To ensure quality of life among HIV+ Chinese individuals, self-efficacy in HIV-related management including substance use and anxiety is the key to suppress viral load and maintain healthy lives. OBJECTIVES: We examine the mediation relationship among substance use, anxiety, and self-management efficacy. METHOD: A cross-sectional study design was used. 137 HIV+ individuals were recruited from two premier Chinese hospitals: Beijing's Ditan Hospital and Shanghai's Public Health Clinic Center (SPHCC). RESULTS: HIV+ substance users had significantly lower HIV-management efficacy and higher anxiety scores. About a third of the relations between substance use and anxiety was mediated by HIV-management self-efficacy. Those who used substances in the previous week had higher anxiety levels suggesting the presence of a recent effect. Their higher levels of anxiety could be largely explained by their lower HIV-management efficacy. CONCLUSION: It is useful for healthcare providers to assess substance use behaviors in HIV+ individuals as well as provide support in managing anxiety in this population. Meanwhile, enhancing self-management efficacy to ensure healthy lifestyles may support achieving optimal lives with HIV.

Clinical characteristics and diagnostic confirmation of Internet addiction in secondary school students in Wuhan, China.

AIM: This study investigated the clinical characteristics of internet addiction using a cross-sectional survey and psychiatric interview. METHODS: A structured questionnaire consisted of demographics, Symptom Checklist 90, Self-Rating Anxiety Scale, Self-Rating Depression Scale, and Young's Internet Addiction Test (YIAT) was administered to students of two secondary schools in Wuhan, China. Students with a score of 5 or higher on the YIAT were classified as having Internet Addiction Disorder (IAD). Two psychiatrists interviewed students with IAD to confirm the diagnosis and evaluate their clinical characteristics. RESULTS: Of a total of 1076 respondents (mean age 15.4 ± 1.7 years; 54.1% boys), 12.6% (n = 136) met the YIAT criteria for IAD. Clinical interviews ascertained the Internet addiction of 136 pupils and also identified 20 students (14.7% of IAD group) with comorbid psychiatric disorders. Results from multinomial logistic regression indicated that being male, in grade 7-9, poor relationship between parents and higher self-reported depression scores were significantly associated with the diagnosis of IAD. CONCLUSION: These results advance our understanding of the clinical characteristics of Internet addiction in Chinese secondary school students and may help clinicians, teachers, and other stakeholders better manage this increasingly serious mental condition.

The reliability of the Chinese version of the Barratt Impulsiveness Scale version 11, in abstinent, opioid-dependent participants in Taiwan.

BACKGROUND: The Barratt Impulsiveness Scale (BIS) is one of the most commonly used self-report measures of trait impulsivity. However, the reliability of this measure among individuals who abuse substances has not yet been well examined. The purpose of this study was to evaluate the reliability and validity of the Chinese version of this measure in abstinent, opioid-dependent participants. METHODS: The opioid-dependent participants were all male inmates recruited from two official correction agencies located in northern Taiwan, from October 2006 to September 2007; of these participants, the retest group completed a second assessment after 1 month. The internal consistency reliability of the BIS version 11 (BIS-11) was assessed by calculating the Cronbach α coefficient. Test-retest reliability was assessed based on intraclass correlation coefficients. Factor validity was examined using principal component analysis. Internal consistency and factor validity of the BIS-11 were investigated in a sample of 153 participants, and test-retest reliability was analyzed in 67 participants. RESULTS: A three-factor structure of BIS-11 representing psychological constructs similar to those originally identified in other translations of the BIS-11 was found. The Cronbach α coefficient for this instrument was 0.83, indicating high internal consistency, and the intraclass correlation coefficient was 0.66, indicating good test-retest reliability. The BIS-11 had highest reliability among participants without a criminal history. The test-retest reliability was still satisfactory among participants with a lower education level or alcohol dependence. CONCLUSION: This study suggests that the Chinese version of the BIS-11 is a reliable measure and has potential utility for investigating impulsivity in opioid-dependent individuals.

Association of frontal and posterior cortical gray matter volume with time to alcohol relapse: a prospective study.

OBJECTIVE: Alcoholism is associated with gray matter volume deficits in frontal and other brain regions. Whether persistent brain volume deficits in abstinence are predictive of subsequent time to alcohol relapse has not been established. The authors measured gray matter volumes in healthy volunteers and in a sample of treatment-engaged, alcohol-dependent patients after 1 month of abstinence and assessed whether smaller frontal gray matter volume was predictive of subsequent alcohol relapse outcomes. METHOD: Forty-five abstinent alcohol-dependent patients in treatment and 50 healthy comparison subjects were scanned once using high-resolution (T(1)-weighted) structural MRI, and voxel-based morphometry was used to assess regional brain volume differences between the groups. A prospective study design was used to assess alcohol relapse in the alcohol-dependent group for 90 days after discharge from 6 weeks of inpatient treatment. RESULTS: Significantly smaller gray matter volume in alcohol-dependent patients relative to comparison subjects was seen in three regions: the medial frontal cortex, the right lateral prefrontal cortex, and a posterior region surrounding the parietal-occipital sulcus. Smaller medial frontal and parietal-occipital gray matter volumes were each predictive of shorter time to any alcohol use and to heavy drinking relapse. CONCLUSIONS: These findings are the first to demonstrate that gray matter volume deficits in specific medial frontal and posterior parietal-occipital brain regions are predictive of an earlier return to alcohol use and relapse risk, suggesting a significant role for gray matter atrophy in poor clinical outcomes in alcoholism. Extent of gray matter volume deficits in these regions could serve as useful neural markers of relapse risk and alcoholism treatment outcome.

A neural measure of behavioral engagement: task-residual low-frequency blood oxygenation level-dependent activity in the precuneus.

Brain imaging has provided a useful tool to examine the neural processes underlying human cognition. A critical question is whether and how task engagement influences the observed regional brain activations. Here we highlighted this issue and derived a neural measure of task engagement from the task-residual low-frequency blood oxygenation level-dependent (BOLD) activity in the precuneus. Using independent component analysis, we identified brain regions in the default circuit - including the precuneus and medial prefrontal cortex (mPFC) - showing greater activation during resting as compared to task residuals in 33 individuals. Time series correlations with the posterior cingulate cortex as the seed region showed that connectivity with the precuneus was significantly stronger during resting as compared to task residuals. We hypothesized that if the task-residual BOLD activity in the precuneus reflects engagement, it should account for a certain amount of variance in task-related regional brain activation. In an additional experiment of 59 individuals performing a stop signal task, we observed that the fractional amplitude of low-frequency fluctuation (fALFF) of the precuneus but not the mPFC accounted for approximately 10% of the variance in prefrontal activation related to attentional monitoring and response inhibition. Taken together, these results suggest that task-residual fALFF in the precuneus may be a potential indicator of task engagement. This measurement may serve as a useful covariate in identifying motivation-independent neural processes that underlie the pathogenesis of a psychiatric or neurological condition.

Functional connectivity delineates distinct roles of the inferior frontal cortex and presupplementary motor area in stop signal inhibition.

The neural basis of motor response inhibition has drawn considerable attention in recent imaging literature. Many studies have used the go/no-go or stop signal task to examine the neural processes underlying motor response inhibition. In particular, showing greater activity during no-go (stop) compared with go trials and during stop success compared with stop error trials, the right inferior prefrontal cortex (IFC) has been suggested by numerous studies as the cortical area mediating response inhibition. Many of these same studies as well as others have also implicated the presupplementary motor area (preSMA) in this process, in accord with a function of the medial prefrontal cortex in goal-directed action. Here we used connectivity analyses to delineate the roles of IFC and preSMA during stop signal inhibition. Specifically, we hypothesized that, as an integral part of the ventral attention system, the IFC responds to a stop signal and expedites the stop process in the preSMA, the primary site of motor response inhibition. This hypothesis predicted that preSMA and primary motor cortex would show functional interconnectivity via the basal ganglia circuitry to mediate response execution or inhibition, whereas the IFC would influence the basal ganglia circuitry via connectivity with preSMA. The results of Granger causality analyses in 57 participants confirmed this hypothesis. Furthermore, psychophysiological interaction showed that, compared with stop errors, stop successes evoked greater effective connectivity between the IFC and preSMA, providing additional support for this hypothesis. These new findings provided evidence critically differentiating the roles of IFC and preSMA during stop signal inhibition and have important implications for our understanding of the component processes of inhibitory control.

Gender Differences in Cognitive Control: an Extended Investigation of the Stop Signal Task.

Men and women show important differences in clinical conditions in which deficits in cognitive control are implicated. We used functional magnetic resonance imaging to examine gender differences in the neural processes of cognitive control during a stop-signal task. We observed greater activation in men, compared to women, in a wide array of cortical and sub-cortical areas, during stop success (SS) as compared to stop error (SE). Conversely, women showed greater regional brain activation during SE > SS, compared to men. Furthermore, compared to women, men engaged the right inferior parietal lobule to a greater extent during post-SE go compared to post-go go trials. Women engaged greater posterior cingulate cortical activation than men during post-SS slowing in go trial reaction time (RT) but did not differ during post-SE slowing in go trial RT. These findings extended our previous results of gender differences in regional brain activation during response inhibition. The results may have clinical implications by, for instance, helping initiate studies to understand why women are more vulnerable to depression while men are more vulnerable to impulse control disorders.

Decreased amygdala activation during risk taking in non-dependent habitual alcohol users: A preliminary fMRI study of the stop signal task.

BACKGROUND AND OBJECTIVES: Habitual alcohol use is prodromal to alcohol dependence. It has been suggested that impairment in impulse control contributes to habitual drinking. Little is known whether neural processes associated with impulse control is altered in non-dependent social drinkers. The current preliminary study combined functional magnetic resonance imaging and the stop signal task (SST) to address this issue. METHODS: We compared non-dependent non/light (n = 12) and moderate/heavy (n = 9) young adult alcohol drinkers in a SST, in which they were required to exercise inhibitory control during the stop trials and were engaged in a speed/accuracy trade-off during trial-to-trial go responses. Our previous studies identified neural correlates of inhibitory control and risk taking during the SST ( [10] , [11] ). Furthermore, alcohol dependent patients showed altered brain activation both during inhibitory control and risk taking, compared to healthy controls ( [12] ). RESULTS: We showed that moderate/heavy alcohol drinkers were decreased in amygdala activation during risk taking, while indistinguishable in neural measures of inhibitory control, when compared to non/light drinkers. CONCLUSIONS AND SIGNIFICANCE: Altered amygdala activation during risk taking may be a key neural process underlying early habitual alcohol use and a potential marker mediating transition to alcohol dependence.

Altered impulse control in alcohol dependence: neural measures of stop signal performance.

BACKGROUND: Altered impulse control has been implicated in the shaping of habitual alcohol use and eventual alcohol dependence. We sought to identify the neural correlates of altered impulse control in 24 abstinent patients with alcohol dependence (PAD), as compared to 24 demographics matched healthy control subjects (HC). In particular, we examined the processes of risk taking and cognitive control as the neural endophenotypes of alcohol dependence. METHODS: To this end, functional magnetic resonance imaging (fMRI) was conducted during a stop signal task (SST), in which a procedure was used to elicit errors in the participants. The paradigm allowed trial-by-trial evaluation of response inhibition, error processing, and post-error behavioral adjustment. Furthermore, by imposing on the subjects to be both fast and accurate, the SST also introduced a distinct element of risk, which participants may or may not avert during the task. Brain imaging data were analyzed with Statistical Parametric Mapping in covariance analyses accounting for group disparity in general performance. RESULTS: The results showed that, compared to HC, PAD demonstrated longer go trial reaction time (RT) and higher stop success rate (SS%). HC and PAD were indistinguishable in stop signal reaction time (SSRT) and post-error slowing (PES). In a covariance analysis accounting for go trial RT and SS%, HC showed greater activity in the left dorsolateral prefrontal cortex than PAD, when subjects with short and long SSRT were contrasted. By comparing PAD and HC directly during stop errors (SE), as contrasted with SS, we observed greater activity in PAD in bilateral visual and frontal cortices. Compared to HC, PAD showed less activation of the right dorsolateral prefrontal cortex during PES, an index of post-error behavioral adjustment. Furthermore, PAD who showed higher alcohol urge at the time of the fMRI were particularly impaired in dorsolateral prefrontal activation, as compared to those with lower alcohol urge. Finally, compared to HC subjects, PAD showed less activity in cortical and subcortical structures including putamen, insula, and amygdala during risk-taking decisions in the SST. CONCLUSION: These preliminary results provided evidence for altered neural processing during impulse control in PAD. These findings may provide a useful neural signature in the evaluation of treatment outcomes and development of novel pharmacotherapy for alcohol dependence.

Neural correlates of speeded as compared with delayed responses in a stop signal task: an indirect analog of risk taking and association with an anxiety trait.

The stop signal task (SST) is widely used to explore neural processes involved in cognitive control. By randomly intermixing stop and go trials and imposing on participants to respond quickly to the go but not the stop signal, the SST also introduces an indirect element of risk, which participants may avert by slowing down or ignore by responding "as usual," during go trials. This "risk-taking" component of the SST has to our knowledge never been investigated. The current study took advantage of variability of go trial reaction time (RT) and compared the post-go go trials that showed a decrease in RT (risk-taking decision) and those post-go go trials that showed an increase in RT ("risk-aversive" decision) in 33 healthy individuals who underwent functional magnetic resonance imaging during the SST. This contrast revealed robust activation in bilateral visual cortices as well as left inferior parietal and posterior cingulate cortices, amygdala, and middle frontal gyrus (P < 0.05, family-wise error [FWE] corrected). Furthermore, we observed that the magnitude of amygdala activity is positively correlated with trait anxiety of the participants. These results thus delineated, for the first time, a neural analog of risk taking during stop signal performance, highlighting a novel aspect and broadening the utility of this behavioral paradigm.

Subcortical processes of motor response inhibition during a stop signal task.

Previous studies have delineated the neural processes of motor response inhibition during a stop signal task, with most reports focusing on the cortical mechanisms. A recent study highlighted the importance of subcortical processes during stop signal inhibition in 13 individuals and suggested that the subthalamic nucleus (STN) may play a role in blocking response execution (Aron and Poldrack, 2006. Cortical and subcortical contributions to Stop signal response inhibition: role of the subthalamic nucleus. J Neurosci 26, 2424-2433). Here in a functional magnetic resonance imaging (fMRI) study we replicated the finding of greater activation in the STN during stop (success or error) trials, compared to go trials, in a larger sample of subjects (n=30). However, since a contrast between stop and go trials involved processes that could be distinguished from response inhibition, the role of subthalamic activity during stop signal inhibition remained to be specified. To this end we followed an alternative strategy to isolate the neural correlates of response inhibition (Li et al., 2006a. Imaging response inhibition in a stop signal task--neural correlates independent of signal monitoring and post-response processing. J Neurosci 26, 186-192). We compared individuals with short and long stop signal reaction time (SSRT) as computed by the horse race model. The two groups of subjects did not differ in any other aspects of stop signal performance. We showed greater activity in the short than the long SSRT group in the caudate head during stop successes, as compared to stop errors. Caudate activity was positively correlated with medial prefrontal activity previously shown to mediate stop signal inhibition. Conversely, bilateral thalamic nuclei and other parts of the basal ganglia, including the STN, showed greater activation in subjects with long than short SSRT. Thus, fMRI delineated contrasting roles of the prefrontal-caudate and striato-thalamic activities in mediating motor response inhibition.

Inhibitory control and emotional stress regulation: neuroimaging evidence for frontal-limbic dysfunction in psycho-stimulant addiction.

This review focuses on neuroimaging studies that examined stress processing and regulation and cognitive inhibitory control in patients with psycho-stimulant addiction. We provide an overview of these studies, summarizing converging evidence and discrepancies as they occur in the literature. We also adopt an analytic perspective and dissect these psychological processes into their sub-components, to identify the neural pathways specific to each component process and those that are more specifically involved in psycho-stimulant addiction. To this aim we refer frequently to studies conducted in healthy individuals. Despite the separate treatment of stress/affect regulation, stress-related craving or compulsive drug seeking, and inhibitory control, neural underpinnings of these processes overlap significantly. In particular, the ventromedial prefrontal regions including the anterior cingulate cortex, amygdala and the striatum are implicated in psychostimulant dependence. Our overarching thesis is that prefrontal activity ensures intact emotional stress regulation and inhibitory control. Altered prefrontal activity along with heightened striatal responses to addicted drug and drug-related salient stimuli perpetuates habitual drug seeking. Further studies that examine the functional relationships of these neural systems will likely provide the key to understanding the mechanisms underlying compulsive drug use behaviors in psycho-stimulant dependence.

Neural correlates of post-error slowing during a stop signal task: a functional magnetic resonance imaging study.

The ability to detect errors and adjust behavior accordingly is essential for maneuvering in an uncertain environment. Errors are particularly prone to occur when multiple, conflicting responses are registered in a situation that requires flexible behavioral outputs; for instance, when a go signal requires a response and a stop signal requires inhibition of the response during a stop signal task (SST). Previous studies employing the SST have provided ample evidence indicating the importance of the medial cortical brain regions in conflict/error processing. Other studies have also related these regional activations to postconflict/error behavioral adjustment. However, very few studies have directly explored the neural correlates of postconflict/error behavioral adjustment. Here we employed an SST to elicit errors in approximately half of the stop trials despite constant behavioral adjustment of the observers. Using functional magnetic resonance imaging, we showed that prefrontal loci including the ventrolateral prefrontal cortex are involved in post-error slowing in reaction time. These results delineate the neural circuitry specifically involved in error-associated behavioral modifications.

Neural correlates of impulse control during stop signal inhibition in cocaine-dependent men.

Altered impulse control is associated with substance use disorders, including cocaine dependence. We sought to identify the neural correlates of impulse control in abstinent male patients with cocaine dependence (PCD). Functional magnetic resonance imaging (fMRI) was conducted during a stop signal task that allowed trial-by-trial evaluation of response inhibition. Fifteen male PCD and 15 healthy control (HC) subjects, matched in age and years of education, were compared. Stop signal reaction time (SSRT) was derived on the basis of a horse race model. By comparing PCD and HC co-varied for stop success rate, task-related frustration rating, and post-error slowing, we isolated the neural substrates of response inhibition, independent of attentional monitoring (of the stop signal) and post-response processes including affective responses and error monitoring. Using region of interest analysis, we found no differences between HC and PCD who were matched in stop signal performance in the pre-supplementary motor area (pre-SMA) previously shown to be associated with SSRT. However, compared with HC, PCD demonstrated less activation of the rostral anterior cingulate cortex (rACC), an area thought to be involved in the control of stop signal inhibition. The magnitude of rACC activation also correlated negatively with the total score and the impulse control subscore of the Difficulty in Emotion Regulation Scale in PCD. The current study thus identified the neural correlates of altered impulse control in PCD independent of other cognitive processes that may influence stop signal performance. Relative hypoactivation of the rACC during response inhibition may represent a useful neural marker of difficulties in impulse control in abstinent cocaine-dependent men who are at risk of relapse.

Greater activation of the "default" brain regions predicts stop signal errors.

Previous studies have provided evidence for a role of the medial cortical brain regions in error processing and post-error behavioral adjustment. However, little is known about the neural processes that precede errors. Here in an fMRI study we employ a stop signal task to elicit errors approximately half of the time despite constant behavioral adjustment of the observers (n=40). By comparing go trials preceding a stop error and those preceding a stop success, we showed that (at p<0.05, corrected for multiple comparisons) the activation of midline brain regions including bilateral precuneus and posterior cingulate cortices, perigenual anterior cingulate cortices and transverse frontopolar gyri precedes errors during the stop signal task. Receiver operating characteristic (ROC) analysis based on the signal detection theory showed that the activity in these three regions predicts errors with an accuracy between 0.81 and 0.85 (area under the ROC curve). Broadly supporting the hypothesis that deactivation of the default mode circuitry is associated with mental effort in a cognitive task, the current results further indicate that greater activity of these brain regions can precede performance errors.

Obsessive-compulsiveness and impulsivity in a non-clinical population of adolescent males and females.

Obsessive-compulsive and impulsive behaviors co-occur in certain psychiatric conditions. Some have suggested that these disturbances constitute a spectrum of altered psychologies and behaviors that share an underlying neuropathology. We investigate here whether obsessive-compulsiveness and impulsivity reflect related psychological dimensions in a non-clinical adolescent population. Out of 720 high-school students, 672 and 682 completed a questionnaire interview with a Chinese version of the Maudsley Obsessive-Compulsive Inventory (MOCI) and the Barratt Impulsiveness Scale (BIS-11), respectively. Both MOCI and BIS-11 demonstrated good overall internal consistency, each with three major factors identified with Principal Component Analysis. In the 638 participants who completed both questionnaires, the total MOCI and BIS-11 scores did not correlate with each other. However, the MOCI factor "repetitive checking and attention to details" correlated negatively with the BIS-11 factor "inability to plan and look ahead" for all participants, and for males and females separately. The same MOCI factor also correlated negatively with the BIS-11 factors "lack of perseverance and self-control" and "novelty-seeking and acting without thinking" for all participants, and for females but not for males. The MOCI factor "doubt and intrusive thoughts" correlated positively with the BIS-11 factor "lack of perseverance and self-control" for all participants, and for males but not for females. These results suggested that the relationship between obsessive-compulsiveness and impulsivity as measured by the MOCI and the BIS-11 is complicated, with gender playing an important modulatory role. We discuss the relevance of these findings to developing a conceptual scheme to characterize and study the neurobiological basis of obsessive-compulsive and impulsive behaviors.