Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder divided into three subtypes: inattentive, hyperactive-impulsive, and combined type (Diagnostic and Statistical Manual of Mental Disorders; DSM-5; APA, 2013). The inattentive subtype is characterized by attention deficits, while difficulties in controlling behavior characterize the hyperactive-impulsive subtype. The combined subtype includes both attention deficits and hyperactive-impulsive symptoms. These three core symptoms of ADHD (inattention, impulsivity, and hyperactivity) may lead to feelings of frustration, poor planning and poor decision-making (Young & Gudjonsson, 2006), dysfunctional interpersonal relationships (Edel et al., 2010; McKee, 2017; Shaw-Zirt et al., 2005), and impaired academic performance (Heiligenstein et al., 1999). These, in turn, may impair the ability of these individuals to adapt and cope within the environment (Young & Gudjonsson, 2006).
Some of the difficulties individuals with ADHD face may be explained by impairment in emotion regulation (Seymour et al., 2014). Specifically, compared to controls, individuals with ADHD exhibit a higher prevalence of emotion regulation difficulties, especially in stressful and frustrating situations (Graziano & Garcia, 2016; Walcott & Landau, 2004). Among these emotion regulation difficulties is a reduced tendency to use reappraisal (Van Cauwenberge et al., 2017). Reappraisal is an adaptive emotion regulation strategy in which the individual thinks differently about a situation to reduce negative feelings (Aldao et al., 2010; Gross & John, 2003).
Reappraisal is associated with improved emotional health (Aldao et al., 2010; Gross & John, 2003) and has been found to moderate the link between stress and inattention symptoms (Shahane et al., 2019). Namely, while inattention problems are usually associated with increased perceived stress, this link is weaker among individuals who have a greater tendency to engage in reappraisal (Shahane et al., 2019). Therefore, it is unfortunate that individuals with ADHD symptoms tend to use reappraisal less frequently than controls (Shushakova et al., 2018), which has been suggested to explain their elevated feelings of distress, anger, guilt, and shame (Christian et al., 2020). Nevertheless, when instructed to employ reappraisal, individuals with ADHD symptoms can use this strategy to reduce negative feelings (Kronenberg et al., 2015; Young & Bramham, 2006).
Recent notions argue that reappraisal may depend on cognitive control (Ochsner et al., 2012). Cognitive control comprises the set of processes that enable individuals to behave according to their goals and ignore irrelevant information. Similarly, reappraisal involves the suppression of irrelevant information in order to perform goal-oriented behavior (Bartholomew et al., 2021). Indeed, several studies found a positive link between cognitive control and reappraisal (Beauchamp et al., 2016; Cohen & Mor, 2018; Hendricks & Buchanan, 2016; Malooly et al., 2013; McRae et al., 2012; Tabibnia et al., 2011). For example, McRae et al. (2012) found that reappraisal is positively associated with specific cognitive control components (working memory capacity and set-shifting costs) for both emotional and neutral material. Similarly, greater use of reappraisal was found to be associated with less emotional interference by aversive images following a flanker task that recruits inhibitory control (Cohen et al., 2012).
The findings mentioned above show a correlational link between the tendency to use reappraisal and cognitive control. Studies have only recently begun testing whether there is a causal link between cognitive control and the propensity to use reappraisal and between cognitive control and the ability to implement reappraisal when facing a negative event. One way of assessing this causal link is by training individuals with a cognitive control task and measuring whether such training increases the propensity to use reappraisal or the effectiveness of an instructed reappraisal assignment. The results of these studies are inconsistent, with some findings showing that cognitive control training can enhance the use and effectiveness of cognitive reappraisal (Aker et al., 2014; Cohen & Mor, 2018; Pan et al., 2020; Peckham & Johnson, 2018; Schweizer et al., 2013; Sanchez et al., 2016; Xiu et al., 2016), while others fail to find such an effect (e.g., Gan et al., 2017; Hoorelbeke et al., 2016). For example, Cohen and Mor (2018) showed that a training procedure in which participants recruit cognitive control before the presentation of negative pictures enhances reappraisal propensity and the ability of instructed reappraisal to reduce negative mood. In their study, healthy individuals completed a task in which a flanker stimulus was shown before a negative or a neutral picture. Incongruent flanker stimuli consist of a conflict between the target and distractors and are therefore associated with recruitment of cognitive control. Reaction time (RT) to a discrimination task (deciding whether a square is blue or green) at the end of the trial was used to assess the effect of incongruent flankers on emotional processing. The authors paired the appearance of incongruent flanker stimuli (that recruit cognitive control) with negative pictures. Therefore, in the training group, participants recruited cognitive control before encountering the emotional information in most (80%) of the trials. In the control group, however, most of the negative pictures were preceded by a congruent flanker stimulus, which does not recruit cognitive control. Following this task, the two groups were asked to recall a personal negative event and reappraise it. The results revealed less emotional interference by negative pictures on reaction times of the discrimination target when these pictures appeared following the recruitment of cognitive control (incongruent flanker stimuli; see also Cohen et al., 2012, 2014). Compared to the control group, the training group reported higher use of reappraisal after recalling the event and greater success in the instructed reappraisal assignment, as indicated by a larger reduction in negative mood. These results are in line with findings showing that transcranial direct current stimulation (tDCS) on brain regions associated with cognitive control decreases arousal ratings in a reappraisal task (Feeser et al., 2014).
The role of cognitive control in emotion regulation may be especially relevant in the context of ADHD. Individuals with ADHD symptoms show deficits in cognitive control (Barkley, 1997; Sergeant et al., 2002; Willcutt et al., 2005), what may explain their emotion regulation difficulties (Franklin et al., 2017; Smallwood & Andrews-Hanna, 2013). This idea is in line with findings showing that these individuals have difficulties ignoring irrelevant information (Barkley, 1997; Hwang et al., 2015), both neutrally and emotionally valenced (Manoli et al., 2020). Inability to ignore irrelevant emotional information is indeed associated with reduced ability to use reappraisal (Cohen et al., 2012) and with elevated levels of depression and rumination (Cohen et al., 2015; Joormann & Gotlib, 2010). Prior studies on ADHD assessed either deficits in cognitive control or deficits in emotion regulation, and therefore it is yet unknown whether cognitive control plays a role in enabling adaptive emotion regulation use among this population.
The current study is the first to examine whether a training procedure in which cognitive control is employed over negatively valenced stimuli can enhance reappraisal ability among individuals reporting high levels of ADHD symptoms. Individuals who reported having ADHD symptoms and controls performed a training task in which cognitive control recruitment (i.e., incongruent flanker stimulus) was paired with negative pictures (high emotion control; H-EC condition) or with neutral pictures (low emotion control; L-EC condition). Reaction time (RT) to a discrimination task (deciding whether a square is blue or green) that appeared at the end of the trial was used to assess the influence of cognitive control on emotional interference. Following the training task, participants were asked to recall a negative personal event and to reappraise it. (Cohen & Mor, 2018). Based on prior literature showing difficulties both in emotion regulation (Hwang et al., 2015; Barkley, 1997) and cognitive control (Ramsay, 2010; Sergeant et al., 2002; Willcutt et al., 2005) among individuals with ADHD symptoms, we expected the high emotion control (H-EC) training would be highly beneficial for these individuals. Specifically, we predicted that similar to what was found in Cohen & Mor (2018), compared to the L-EC condition, participants in the H-EC condition would show a greater propensity to use reappraisal, as well as greater success in implementing the instructed reappraisal assignment, as indicated by a reduction in negative mood. These effects were expected to be larger among individuals reporting high levels of ADHD symptoms compared to the control group.