Self-control can be seen as an umbrella construct that bridges concepts from different disciplines (e.g., executive function, impulse control, attention-regulation, emotion-regulation, planning, delay of gratification, and cognitive flexibility) [1, 2]. Poor self-control is an important feature of psychiatric disorders arising in childhood and adolescence, including Attention Deficit/Hyperactivity Disorder (ADHD), oppositional defiant disorder (ODD), conduct disorder (CD), mood and anxiety disorders, substance use disorder, and gambling [3,4,5]. Early self-control predicts not only mental and physical health, but also current and later academic performance, wealth, criminality and parenting [1, 6,7,8]. For example, children with poor self-control at preschool age have been shown to be more likely to have substance dependence, financial troubles and a criminal record at age 32 [1]. Therefore, targeting self-control in interventions for youth with deficits in self-control appears of utmost importance.
Self-control can be trained, although it is unclear which interventions are most effective in improving self-control in youth [9]. Mindfulness-Based Interventions (MBIs) use exercises that train self-control capacities [10] and are increasingly gaining ground as an approach to increase self-control in youth [11, 12]. Mindfulness is often defined as the trainable capacity to pay attention to experiences in the present moment, on purpose and without judgement [13, 14]. It has been suggested that MBIs enhance self-regulation through three interacting processes: enhanced attention control, improved emotional regulation, and altered self-awareness (diminished self-referential processing and enhanced body awareness) [15]. This is supported by an activation likelihood estimation meta-analysis of 21 structural neuroimaging studies in ~ 300 adult (mindfulness) meditation practitioners, showing that neural correlates of these cognitive processes are altered in meditators compared to non-meditators with a global medium effect size [16]. In addition, 78 functional neuroimaging studies were reviewed in an activation likelihood estimation meta-analysis with 527 healthy non-clinical adult meditation practitioners who actually meditated during scanning. The results indicate dissociable brain (de)activation patterns during different styles of meditation, which are congruent with the psychological and behavioural aims of each practice [17]. If neural mechanisms underlying self-control can be altered structurally and functionally by meditation practices, this likely results in effects on behavioural and cognitive measures of self-control as well.
Previous clinical trials show that self-control can be improved following MBIs in diverse populations. Randomised Controlled Trials (RCTs) show greater improvement after MBIs than active control conditions in executive functions of adults (undergraduates, N = 80), adolescents (middle and high school students, N = 489) and children (4–5 years, N = 60) [18]. A meta-analysis on neuropsychological outcomes of MBIs in adult populations (clinical and non-clinical) found preliminary evidence for positive effects on general awareness and meta-awareness, cognitive flexibility and working memory [19]. However, evidence was weak for improvement of attentional control (alerting/sustained attention, orienting/selective attention and executive attention), executive function inhibition and mental set shifting. For youth (5–18 years old), a systematic review of interventions with a focus on yoga-, meditation-, and/or mindfulness-based techniques found significant effects of the interventions on attention and executive functioning with medium to large effect sizes in five of the thirteen included studies. However, study populations consisted of both non-clinical and clinical populations and methodological quality of the studies varied [20]. A meta-analysis of MBIs with youth found significantly higher effect sizes for clinical samples than for non-clinical samples [21]. In addition, an RCT found that specifically children with poor executive functioning show improvement in this area based on teacher and parent reports [22]. Hence, effectiveness of MBIs in increasing self-control may be greater in a more homogeneous clinical population with self-control difficulties.
As a consequence, MBIs are increasingly applied as an approach in the treatment of ADHD in which deficits in self-control are a central component [23]. ADHD is a common neurodevelopmental disorder characterised by impairing symptoms of inattention and hyperactivity-impulsivity, affecting 5–7.5% of all children worldwide [24]. The annual health care costs and societal ‘costs of illness’ of ADHD in youth are high and comparable in magnitude to other serious medical problems (e.g. stroke, asthma in children) and mental health problems (e.G. major depressive disorder) [25]. Furthermore, ADHD has a significant impact on the quality of life of the affected children comparable to other mental health conditions (e.g. anxiety disorders, autism spectrum disorders (ASD), mood disorders) and severe physical disorders (e.g. cerebral palsy, cancer) [26, 27]. Moreover, quality of life of parents is also negatively affected by ADHD of their child, for example in terms of their psychological well-being, personal fulfilment, family and couple relationships and daily life activities [28].
Current care-as-usual (CAU) for children with ADHD consists of psychoeducation, pharmacotherapy and/or (cognitive-) behavioural treatments [29, 30]. Psychoeducation enhances parents’ knowledge about ADHD and may enhance engagement in psychopharmacological treatment [31]. Pharmacotherapy can be effective in reducing core symptoms of ADHD and to a lesser extent improving other outcomes like quality of life, functioning [32], response inhibition, sustained attention and working memory [33]. However, pharmacotherapy can be hampered by side effects and low adherence [34,35,36,37,38]. Meta-analyses of (cognitive) behavioural interventions in the treatment of youth with ADHD show that these can improve parenting behaviour, increase parents’ sense of self-worth and reduce child conduct problems. Specific modules may improve child social skills and academic functioning [31]. Nevertheless, this review also shows that behavioural treatment does not reduce observer rated ADHD symptoms of the child and no support was found for its effects on parental mental well-being [31, 39]. Moreover, cognitive training of attention and executive functioning in children with ADHD does not yield significant improvements in these areas [40]. Another limitation of both pharmacotherapy and behavioural interventions for ADHD is that treatment is less effective when parents have ADHD themselves [31, 41]. As ADHD runs in families and is highly heritable, this is often the case [42, 43]. In conclusion, CAU for ADHD is not sufficient for many families and a substantial subgroup of children with ADHD has remaining symptoms and impairment [44, 45]. MBIs for children and their parents are promising in targeting self-control, behavioural symptoms and parental outcomes [46,47,48,49].
Previous studies on MBIs as a treatment approach for youth with ADHD have been reviewed in several publications. A meta-analysis of studies on pre-post effects of MBIs on ADHD core symptoms in children and adults diagnosed with ADHD [50] yields an overall effect size of d = −.66 for reduction of inattention symptoms and d = −.53 for reduction of hyperactivity/impulsivity symptoms. In a subgroup analysis of the six included trials in children and adolescents only, medium effect sizes were calculated for both inattention (d = −.66) and hyperactivity/impulsivity (d = −.47). Next to effects on ADHD core symptoms, other clinical effects in children with an ADHD diagnosis (≤ 18 years) and their parents were studied in a systematic review which included a broader range of interventions, i.e. studies with an intervention focusing on mindfulness and/or yoga techniques with either parents, children and/or parents plus children [51]. Eight of the sixteen studies targeted children only and another eight studies investigated a family-based intervention. Positive results were found for improvements after meditation-based interventions in parent-reports of child functioning, parent and/or teacher-reports of child internalising/externalising behaviour, parental ADHD symptoms, parental satisfaction, parent–child relationships and parental happiness, but not in child self-reported happiness. Mixed or limited evidence was found for improvements in child ADHD symptoms, child self-esteem, child social functioning, child academic performance, child self-report of functioning, child-report of internalising/externalising symptoms and parental stress and over reactivity of the parent. Finally, larger effect sizes in child outcomes, lower incidence of poorer outcomes, and more favourable outcomes for parents resulted from trials with family-based interventions compared to child-only interventions. In conclusion, previous research on the effectiveness of MBIs in the treatment of youth with ADHD shows these are feasible interventions for ADHD with potential benefits across a broad range of outcomes including ADHD symptoms, well-being and outcomes for parents. However, the results above should be interpreted with caution due to limited methodological quality of the reviewed studies. It is of note that none of the systematic reviews on MBIs for youth with ADHD focused on self-control in particular.
A few clinical trials looked at effects of MBIs on self-control as assessed with neurocognitive tests and/or with questionnaires in youth with ADHD. In a first RCT, comparing a family MBI with a waitlist control group in children with ADHD aged five to seven years (N = 100) and their parents, significantly greater improvement in the family MBI group compared to control group was found for child executive attention (conflict monitoring)(d = .41) [52]. This result is in line with a quasi-experimental trial on neurocognitive task performance following an MBI in adolescents (N = 8) and adults (N = 24) with ADHD, which also found significant improvements for measures of executive attention. In addition, significant effects were found for set-shifting [53]. A pilot pre-post-intervention study with a family MBI in children aged eight to twelve years (n = 11) found significant improvement with large effect sizes on objective attention tests, but not on parent ratings of self-control on the Behaviour Rating Inventory of Executive Function (BRIEF) [54]. In contrast, in a quasi-experimental trial with ten adolescents (aged 11–15 years) following a family MBI, self-control assessed with the BRIEF improved significantly at 8-weeks follow-up, but only according to father reports and not mother reports [55]. For youth with ADHD, no RCT has been published on effects of MBIs on ecologically valid questionnaire ratings of self-control (e.g. BRIEF). In adults with ADHD, a randomised waitlist controlled MBI trial (N = 20) resulted in significant group differences at the end of treatment favouring the MBI group on self-reported self-control (assessed in the laboratory and with ecological momentary assessment) and clinician rated self-control with large effect sizes. In contrast, no significant improvement was observed with the objective self-control tasks [56]. In another waitlist RCT on an MBI in adults with ADHD (N = 103), self-control as assessed with the BRIEF improved with a large effect size (d = .93) as well [57]. Furthermore, in a randomised CAU controlled MBI trial in 120 adults with ADHD, improvement on the BRIEF over time after MBI + CAU compared with CAU only was found, resulting in an effect size of d = .49 at 6-month follow-up [58]. In summary, implementing MBIs in the treatment of youth with ADHD to improve self-control is promising. Although there are preliminary positive results, the existing evidence in youth is insufficient due to a lack of studies with good methodological quality. RCTs with sufficient power are needed.
The current protocol describes an RCT comparing an 8-week family MBI for youth with ADHD and their parents (MYmind) in addition to CAU with continuation of CAU only. Participating children will have an ADHD diagnosis and comorbidities will be allowed (including ASD). The primary, secondary and tertiary aims correspond to the primary, secondary and tertiary measures that will be used in this study. The primary aim is to investigate the effectiveness of a family MBI in improving self-control of youth with ADHD, as assessed with ecologically valid parent-ratings (BRIEF-P, primary outcome). Different definitions are used in literature on self-control, some take a broad approach, other narrow, and opinions vary on what self-control comprises. We take a broad view on self-control in that it entails self-regulation of behaviour, emotion, cognition and attention. Given the moderate convergent validity of neurocognitive tests of self-control, we prefer ecologically-valid questionnaire ratings of self-control over neurocognitive tests [2]. The predictive validity of behavioural questionnaire ratings of self-control on clinically and societally relevant objective outcomes even decades later (e.g. months unemployed, single parenthood, criminal conviction) has been documented [1, 59]. The secondary aim is to examine the effects of family MBI on child self-control as assessed with teacher-ratings (BRIEF-T) and objective computerised tasks and on psychological symptoms (e.g. ADHD symptoms, symptoms of ASD, brooding), well-being and mindfulness of the children (secondary outcome measures for children). In addition, we aim to examine effects of family MBI on parental self-control as assessed with ecologically valid self-ratings (BRIEF-A) and objective computerised tasks and on psychological symptoms, well-being and mindful parenting of the parents (secondary outcome measures for parents). Our tertiary aim is to look at the effects of family MBI on some exploratory measures such as mind-wandering. Finally, child saliva samples will be collected for (epi)genetic research and qualitative data will be collected to explore effects that are not captured with quantitative assessments and to explore facilitators and barriers of family MBI for youth with ADHD and their parents.
