Department of Psychology, University of Arizona, Tucson, Arizona, USA.
Biol Psychiatry. 2010 Apr 1;67(7):641-8. doi: 10.1016/j.biopsych.2009.10.033. Epub 2009 Dec 24.
Theoretical models have hypothesized that one core problem in attention-deficit/hyperactivity disorder (ADHD) is abnormal reward processing. Temporal reward discounting (decreases in subjective reward value due to prereward delay) is of interest because of its relation with a key symptom of ADHD-impulsivity. This study investigated 1) whether steep temporal reward discounting (TD) is associated with ADHD-combined type (ADHD-C)/symptoms of hyperactivity-impulsivity specifically; 2) the role of reward magnitude in TD in ADHD-C/participants with symptoms of hyperactivity-impulsivity; and 3) whether steep TD in ADHD-C/participants with symptoms of hyperactivity-impulsivity is affected by session length.
Three TD tasks were administered to children and adolescents (aged 6-17) with ADHD-C (n = 25), ADHD-inattentive type (ADHD-I; n = 20), and matched typically developing participants (n = 37). Reward magnitude and session length were varied.
Steep TD was observed in participants with ADHD-C but not in those with ADHD-I, independent of reward magnitude and session length. Dimensional analyses revealed that steep TD was associated with hyperactivity-impulsivity (transcending the arbitrary cutoff for ADHD subtypes), especially when reward magnitude at the trial level was small.
These findings suggest that steep TD in ADHD is best thought of as a correlate of the symptom dimension of hyperactivity/impulsivity. Additionally, steep TD in ADHD is the result of a trade-off between delay and reward magnitude, with all factors contributing to choice preferences. These findings may help refine the delay aversion theory of ADHD, and provide evidence for the notion that unique reward processing is one mechanism associated with symptoms of hyperactivity-impulsivity.
理论模型假设，注意力缺陷/多动障碍（ADHD）的一个核心问题是异常的奖励处理。由于与 ADHD 的一个关键症状——冲动性有关，因此人们对时间奖励折扣（由于预奖励延迟而导致主观奖励价值下降）很感兴趣。本研究调查了 1）是否严重的时间奖励折扣（TD）与 ADHD 混合型（ADHD-C）/多动冲动症状特别相关；2）在 ADHD-C/具有多动冲动症状的参与者中，奖励幅度在 TD 中的作用；3）在 ADHD-C/具有多动冲动症状的参与者中，严重的 TD 是否受会话长度的影响。
对患有 ADHD-C（n = 25）、ADHD 注意力不集中型（ADHD-I；n = 20）和匹配的正常发育参与者（n = 37）的儿童和青少年进行了三个 TD 任务。改变了奖励幅度和会话长度。
在 ADHD-C 参与者中观察到严重的 TD，但在 ADHD-I 参与者中没有观察到，与奖励幅度和会话长度无关。维度分析表明，严重的 TD 与多动冲动有关（超越了 ADHD 亚型的任意截止值），尤其是在试验级奖励幅度较小时。
这些发现表明，ADHD 中的严重 TD 最好被视为多动/冲动症状维度的相关物。此外，ADHD 中的严重 TD 是延迟和奖励幅度之间权衡的结果，所有因素都对选择偏好有贡献。这些发现可能有助于完善 ADHD 的延迟回避理论，并为独特的奖励处理是与多动冲动症状相关的机制之一的观点提供证据。
