Waiting impulsivity: a distinctive feature of ADHD neuropsychology?

Impulsivity is a core feature of attention-deficit hyperactivity disorder (ADHD). It has been conceptualized in a number of different ways. In the current article, we examine how the new concept of “waiting impulsivity”, which refers to premature responding before a scheduled target appears, adds to our understanding of impulsivity in ADHD. Sixty children (8–12 years old; 30 ADHD; 30 typically developing controls) completed the 4-choice serial reaction time task, a measure of waiting impulsivity, alongside tasks measuring inhibitory control and temporal discounting and questionnaires measuring behavioral disorder symptoms, delay aversion, and various aspects of impulsivity. A multiple logistic regression model was used to explore the contribution of the primary task outcomes to predict group membership. Children with ADHD displayed more waiting impulsivity and less inhibitory control; they did not differ in temporal discounting. There was no correlation between waiting impulsivity and inhibitory control. Waiting impulsivity was correlated with parent-reported ratings of hyperactivity/impulsivity, inattention, oppositional defiant disorder (ODD), and conduct disorder (CD) and with self-reported delay aversion ratings. Only waiting impulsivity was a significant predictor of ADHD status. In conclusion, waiting impulsivity is distinct from inhibitory control deficits and predicts ADHD status independently of it. Future research needs to examine the relationship with delay aversion and ODD/CD more thoroughly.     

药物成瘾者决策缺陷的特征、机制及干预

药物成瘾者存在决策缺陷, 并表现出冲动性、风险寻求、奖赏失调、躯体内感信号缺失等特征。神经影像学研究表明药物滥用导致成瘾者背外侧前额皮层、前扣带回、眶额叶皮层、腹内侧前额皮层、杏仁核、脑岛等脑区受损, 这些损伤是引发其决策缺陷的主要原因。认知训练有利于提高个体的决策能力, 如目标管理训练和正念冥想等可以增强个体工作记忆、促进自我觉察和以目标为导向的行为; 而非侵入性脑刺激则可以直接改变与成瘾者决策相关脑区的激活状态, 从而提升与决策相关的认知功能。总体而言, 未来认知训练和非侵入性脑刺激在成瘾干预方面仍有广阔的拓展空间。     

冲动还是习惯?成瘾不同阶段中冲动性的性质与机制

冲动性是一种缺乏充分思考、不顾后果的冒险行为或行为倾向, 它既表现在人格特质中, 也会表现为各类环境中的行为。成瘾者具有典型的冲动性特征, 但成瘾者的冲动性是如何影响和促进成瘾行为的发生、发展, 目前还并不明朗。从成瘾形成的不同阶段, 也许可以对此有更进一步的了解。在药物使用的开始阶段, 冲动性人格特质作为动机原因, 促进成瘾物质的首次使用; 接着操作性条件学习导致用药者进入“目标-导向”阶段, 呈现出选择冲动性。第三阶段, 经典条件学习又使相关线索和药物效应不断匹配, 形成条件反射性药物使用行为。成瘾者进入习惯性用药阶段, 表现出显著的停止冲动性。     

Impulsivity and Behavior-Dependent Life Events Mediate the Relationship of Reward Sensitivity and Depression,but Not Hypomania,Among at-Risk Adolescents

Both reward sensitivity and impulsivity are related to the development and course of bipolar spectrum disorders (BSDs) and have been implicated in other disorders and negative functional outcomes such as substance abuse, obesity, suicidal behaviors, and risk-taking. Furthermore, according to the transactional component of the Behavioral Approach System (BAS)/reward hypersensitivity theory of BSDs, people with reward hypersensitivity should experience more BAS-relevant events, and thus, are more vulnerable to mood symptoms and episodes via stress generation. Impulsivity may exacerbate stress generation in individuals at risk for BSDs based on exhibiting reward hypersensitivity. The current study examined whether impulsivity explained the generation of stress and subsequent mood symptoms beyond what is explained by reward sensitivity alone. Participants were 131 Moderate BAS and 216 High BAS sensitivity adolescents (M = 18.43 years, SD = 1.40), who completed baseline measures of reward sensitivity and impulsivity, as well as follow-up measures of life events and mood symptoms. Results from linear regression analyses indicated that higher baseline impulsivity predicted behavior-dependent, but not behavior-independent, life events. Furthermore, path analyses suggested that the effect of BAS group on depression symptoms at next follow-up was partly explained via the indirect effect of impulsivity and negative behavior-dependent life events. We did not find these effects for behavior-independent or positive-dependent events or for prediction of hypomanic symptoms. The findings suggest that impulsivity may account for stress generation of negative events that precede depression.     

Personality traits of the behavioural approach and inhibition systems: associations with processing of emotional stimuli

This study examined the relationships of the traits associated with Gray's behavioural approach system (BAS) and behavioural inhibition system (BIS) with cognitive processing of emotional information. Initially, participants completed questionnaires covering trait impulsivity and anxiety, and BAS and BIS sensitivities. They were then tested individually. After completing a questionnaire of current positive and negative moods, they completed three tasks measuring processing of pleasant, unpleasant and neutral information. Consistent with Gray’s theory, the results showed that impulsivity and BAS sensitivity were associated with the processing of pleasant information, while anxiety and BIS sensitivity were associated with the processing of unpleasant information. These findings imply that Gray’s BAS–BIS theory can be extended to cognitive processing of emotional information.     

文明的"早生晚熟"和"晚生早熟"--中、英两国文明特征的比较与反思

本文从经济形态、政治制度、社会结构、思想观念、人格特征五个方面对中英两国文明进行观照,认为中英文明分别具有“早生晚熟”和“晚生早熟”的不同特征,而这又是与双方文明进程迥然、专制程度差异、社会结构有别以及对待传统态度不同分不开的。正是这些差别造成了中华文明从先行到落后,而英国文明虽后来反居上。因此,只有丢掉包袱。轻装上阵。中华民族才能浴火重生。     

Delay and Inhibition as Early Predictors of ADHD Symptoms in Third Grade

We used data from a large, longitudinal study of children in the community, the NICHD Study of Early Child Care and Youth Development, to examine how well earlier measures of delay capacity, inhibitory control, planning, and attention predicted symptoms of attention deficit hyperactivity disorder (ADHD) assessed in third grade. Children with elevated symptoms of both inattention and hyperactivity-impulsivity (n = 57) and with inattentive symptoms only (n = 80) were identified via mother and teacher reports using the “or” rule, as were children without significant symptoms (n = 790). Multinomial logistic regression analyses indicated that poorer performance on earlier measures of resistance to temptation, delay of gratification, response inhibition, attention, and planning obtained from 36 months to 1st grade predicted membership in the two symptom groups relative to the comparison group in 3rd grade, albeit with somewhat different patterns of predictors. Controls for 36 month school readiness and externalizing symptoms indicated that these results were generally robust and not an artifact of initial cognitive or behavioral differences. Implications for developmental models of ADHD are discussed.

Self-control: teaching tolerance for delay in impulsive children.

We investigated a procedure to increase the selection of larger, more delayed reinforcers (i.e., more advantageous in the long run) over smaller immediate reinforcers, in an effort to increase a key aspect of self-control in children. Six preschoolers, including one comparison subject, identified by their teachers as impulsive, were preassessed and found consistently to select smaller immediate reinforcers over larger, more delayed ones. The teaching procedure consisted of gradually increasing the durations of the delay interval over many sessions. The follow-up assessments showed that 5 of these children increased the proportion of their choices of the delayed reinforcers. Before training, indifference points ranged from 1.7 to 51.7 s; following treatment, points rose to a range of 37.5 to at least 90 s, with 3 children preferring the larger reinforcer at all delay intervals tested. The results demonstrated the feasibility of teaching young children to make choices more advantageous to them in the long run.