Meditation or Medication? Mindfulness training versus medication in the treatment of childhood ADHD: a randomized controlled trial

Attention-Deficit-Hyperactivity-Disorder (ADHD) is one of the most common childhood disorders, with a prevalence of 5 % [1]. Children and adolescents with ADHD show inattentive, impulsive, and hyperactive behavior that interferes with their (social) functioning or development [1] and occurs in more than one setting (e.g. in social situations, at school, at work, or at home). Following the diagnostic criteria of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [1] inattentive behavior refers to difficulties with organizing and planning tasks or activities and with maintaining attention over prolonged periods of time, such as wandering off during tasks or lacking persistence. Examples of hyperactive behavior are running and climbing in inappropriate situations, fidgeting or tapping with hands or feet, and excessive talking. Impulsivity refers to difficulties with inhibiting proponent responses, such as interrupting or intruding on others’ conversations or activities, answering before a question has been completed, and making important decisions without forethought. Depending on which key symptom is most present, three types of ADHD classifications can be distinguished: a predominantly inattentive presentation (also known as Attention Deficit Disorder, ADD), a predominantly hyperactive/impulsive presentation, or a combined presentation.

It has been demonstrated that children and adolescents diagnosed with ADHD have a substantial economical impact on society [2‐5]. A meta-analysis [2] reviewed seven European-based studies and found that the average total annual costs related to childhood ADHD lie between €9,860 and €14,483 per patient, and national annual costs ranged from €1,041 to €1,529 million. With 648 million, most costs were related to education. Health care costs for childhood ADHD were estimated between €87 and €377 million, and social services costs were €4.3 million per year. From a family perspective, family members of children and adolescents with ADHD add to the economical burden with €161 million of health care costs, and with €143 to €339 million because of productivity losses.

Medication and psychosocial interventions are the most commonly used treatments for reducing ADHD symptoms in children and adolescents [6]. Regarding medication for ADHD, psychostimulants, especially methylphenidate, is globally the most prescribed drug [7] and is being used increasingly since the 1990′s, with a calculated global consumption of 72 tons (2.4 billion defined daily doses for statistical purposes) of methylphenidate in 2013 [8]. Over the years, the highest consumption of methylphenidate took place in the United States. However, since 2000 many other countries, including the Netherlands, show a sharp increase in the use of methylphenidate as well [9, 10]. In the Netherlands 130,000 youngsters were using methylphenidate in 2012 [11], which was at the time 3.2 % of Dutch youngsters [12]. In 2014 the largest group of methylphenidate users were children with ADHD between 11 and 14 years [13], more than 70 out of 1000 children in this age category with ADHD were using methylphenidate. Although the amount of diagnoses in the Netherlands increased over the years, and therefore the use of medication as well, the percentage of children on medication remains stable, which is about two-thirds of the children diagnosed with ADHD and one-third of the children diagnosed with ADD [12]. Many studies have shown that methylphenidate is effective in the treatment of childhood ADHD [14‐16] and that, when controlled for placebo effects, it has beneficial effects for about 70 % of the children with ADHD [17‐19]. According to international guidelines it is recommended to prescribe methylphenidate as a first drug of choice when pharmacological treatment is indicated [20, 21]. Only when this drug does not reach its intended effects, guidelines advise to move on prescribing other medication (mainly dextroamphetamine and atomoxetine). International guidelines further advise that pharmacological treatment should always be part of a more comprehensive treatment program that includes psycho-education and may include behavioral treatment, parent training, and/or teacher-administered behavior therapy [21‐23]. However, guidelines of the American Academy of Child and Adolescent Psychiatry (AACAP) [22] also suggest that when a patient with ADHD experiences robust beneficial effects from pharmacological treatment, and therefore shows normal functioning in several life domains, that this treatment alone is satisfactory. This recommendation is supported by randomized controlled trials (RCTs) such as the Multimodal Treatment of ADHD (MTA) study [24] and a meta-analysis [6], comparing methylphenidate with psychosocial treatment and their combination.

In MTA study [24] 579 children were randomized over 14 months of methylphenidate treatment, intensive behavioral treatment, a combination of these two treatments, or standard community care. Children receiving combined treatment and medical treatment showed a larger decline in ADHD symptoms compared to children receiving behavioral treatment or community care. Moreover, the combined treatment did not have an additive effect in reducing ADHD symptoms compared to medical treatment alone. Van der Oord et al. [6] compared 24 studies, including the MTA study, about the effectiveness of methylphenidate, psychosocial treatment, or their combination in children with ADHD. It was concluded that both methylphenidate and psychosocial treatment were effective in reducing ADHD symptoms, but that psychosocial treatment alone had smaller effects than methylphenidate and a combined treatment. Similar to the findings of the MTA study, in this meta-analysis psychosocial treatment did not show to have additive value to methylphenidate in recuding ADHD sympotms either. Another meta-analysis [25] compared randomized controlled studies evaluating the effects of non-pharmacological treatment for ADHD, both dietary interventions (Restricted Elimination Diets; n = 7, artificial food color exclusions; n = 8, and free fatty acid supplementation; n = 11) and psychosocial interventions (cognitive training; n = 6, neurofeedback; n = 8, and behavioral interventions; n = 15). For all 6 types of interventions results illustrated a reduction in core ADHD symptoms when rated by a person (often unblinded) closest to the therapeutic setting. However, when ratings from persons blind to the treatment condition were evaluated, only free fatty acid supplementation and artificial food color exclusion remained effective in reducing core ADHD symptoms. The authors concluded that the effect sizes found for non-pharmacological treatments are substantially lower than those found in studies on ADHD medication and that better evidence from blinded assessments is needed for psychosocial interventions for ADHD in order to be offered as evidence-based treatments. In an earlier meta-analysis [26], 174 studies on the effectiveness of psychosocial interventions (parent-based, teacher-based, and child-based) for children with ADHD were included. The overall results show that psychosocial interventions are effective in reducing ADHD symptoms and that effect sizes found in this study are comparable to those found for stimulant medication for ADHD. The difference between the latter two meta-analyses is, however, that Sonuga-Barke et al. [25] only included RCTs falling into the highest category of evidence, that is evidence from at least one RCT [27], whereas Fabiano et al. [26] also included studies falling into lower categories of evidence (e.g. uncontrolled studies and single-case studies). Besides, Fabiano et al. [26] included children with externalizing behavior problems but without a diagnosis of ADHD, which may explain part of the highly positive outcomes as well. Lastly, a large recent review on the effects of methylphenidate alone for children and adolescents (n = 12.245, ages ranged from 3 to 21 years) with ADHD included 185 RCTs comparing methylphenidate versus placebo or no intervention [28]. Results show that methylphenidate may reduce the key symptoms of ADHD and may improve general behavior and quality of life. However, due to mostly poor designed research trials and, therefore, high risk of bias for all included studies, the quality of de evidence is low. Better designed RCTs, especially regarding the blinding process, are needed to further establish the evidence of the effectiveness of methylphenidate. Moreover, the authors stress the importance for large RCTs of non-pharmacological treatments for ADHD.

In sum, the international guidelines for treatment of ADHD, supported by the current knowledge about the effectiveness of methylphenidate compared to the somewhat more ambivalent evidence of the effectiveness of other treatment options, suggest that methylphenidate for children with ADHD is, to date, still the first-line treatment [29]. Moreover, looking at the cost effectiveness of medication versus behavioral treatment, medication also seems to be the preferred option as it was estimated that medical costs per child with ADHD is $1079 during a period of 14 months, whereas costs for behavioral treatment per child with ADHD is $7176 during that same period of time [30]. Nevertheless, concerns about the frequency of methylphenidate prescriptions and its possible disadvantages are rising increasingly [8, 31]. These concerns are with good reason, given the literature on the substantial limitations of (stimulant) medication for ADHD. First, usage of stimulant medication may result in side effects such as insomnia, loss of appetite, abdominal pain, headache, anxiety, stress, and nervousness [14, 20, 28, 31, 32]. In the MTA study [24] 64.1 % of the children suffered from one or more mild, moderate, or severe side effects. Second, stimulant medication works only short-term and symptoms return once medication is stopped [20, 33, 34]. Therefore, children with ADHD must continue the use of medication for extended periods of time in order to maintain the beneficial effects [35]. Third, as previously stated, about 70 % of children with ADHD show a symptomatic response to methylphenidate, however, up to 30 % of the children do not benefit from methylphenidate at all [17, 18, 36, 37]. When other pharmacological treatments for ADHD are systematically administered, still 10 % of the children do not respond to any of the medications [24]. Fourth, treatment fidelity is often low with nonadherence rates between 13.2 to 64 % in people with ADHD [38]. Nonadherence is greater for short-acting stimulants compared to long-acting stimulants [7]. Nonadherence may be due to inadequate supervision including delayed or missed doses, but also because patients may forget or refuse to take medication [7]. The most prescribed stimulants are short-acting, including methylphenidate, and require intake of 2 or 3 times a day. As a consequence children need to take medication in public, for example at school, which may be embarrassing or (socially) stigmatizing [7, 39]. Fifth, stimulant medication is a contraindication for people with schizophrenia, hyperthyroidism, cardiac arrhythmias, angina pectoris, and glaucoma. Furthermore, extra caution needs to be taken in case of hypertension, depression, tics, epilepsy, anorexia, autism spectrum disorders, severe mental retardation, or a history of drug abuse or alcoholism [20]. Sixth, the safety of medication for children with ADHD is not fully known [31, 40]. Whereas short-term side effects may be reversible when medication is stopped, little is known about long-term side effects. There is limited literature of the impact of long-term medication use on growth, blood pressure, heart rate, and the occurrence of suicidal, psychotic, and manic symptoms [40]. Some studies found that children with ADHD who take medication for several years show reduced growth and weight compared to their peers [41]. The difference in growth, however, seems to attenuate over time and there is debate about whether the ultimate adult growth is affected. Seventh, the effectiveness of long-term use of methylphenidate is not fully known [40]. Studies on the effectiveness of ADHD medication show robust effects on symptom reduction and other life functioning domains up to 2 years later [42]. So far, little is known about the effectiveness beyond this period. However, results of the MTA study 8-year follow-up data failed to demonstrate the benefits of medication treatment beyond 2 years for most of the children [43].

Because of the above named limitations and uncertainties, children and their parents may not view medication as a considerable option. They are not open to try medication but would like to receive non-pharmacological treatment [7]. To conclude, medication is worldwide the primary treatment of choice for children with ADHD, but has enormous disadvantages, and psychosocial treatments, so far, failed to demonstrate sufficient efficacy. Therefore, there is a large demand for alternative treatment options. Mindfulness training became increasingly popular in the last decade, with studies showing promising results in this burgeoning field, and is for many reasons a potential contender in the treatment for childhood ADHD.

Mindfulness training is an intervention based on Eastern meditation techniques, that aims to increase awareness by paying attention on purpose in the present moment, enhance non-judgmental observation, and reduce automatic responding [44]. Individuals are encouraged to direct their attention towards internal experiences such as bodily sensations, emotions, thoughts, and action tendencies, as well as to environmental stimuli such as smells and sounds in their surroundings [45]. The ability to focus and sustain attention in the present moment and to bring back the attention to the present moment whenever it wandered off, which is trained during a mindfulness course, may be especially beneficial for children diagnosed with ADHD, as 1 of the core symptoms of ADHD is inattention. Practicing mindfulness may give children more control over their attention, which may, in turn, be beneficial for other psychological symptoms as well [46‐48]. Furthermore, the ongoing streams of internal and external stimuli that enter 1’s awareness are to be observed without evaluating or judging them [45]. By doing so, 1 learns -by first person experience- to be accepting of whatever is present, independent from the valence of the stimulus. Patterns of thoughts, emotions, and reactions will be recognized, and hence, by consciously bringing attention to them, these automatic patterns can be interrupted. Individuals learn to respond rather than to react to stimuli. This ability also may be especially beneficial for children diagnosed with ADHD, as the other core symptom is hyperactive and impulsive behavior. By noticing which impulses are arising or the tendency to react hyperactive, 1 creates the possibility to choose how to respond, rather than to react on automatic pilot.

Mindfulness meditation has been incorporated into programs such as Mindfulness Based Stress Reduction (MBSR) [49] and Mindfulness Based Cognitive Therapy (MBCT) [50]. MBSR was originally developed for chronic pain patients in order to help them cope with their illness, whereas MBCT (mindfulness meditation incorporated with cognitive therapy) was developed as a relapse prevention method for patients suffering from recurring depression. Evidence from a large number of studies suggests that mindfulness based interventions are associated with positive psychological effects, such as improved well-being, quality of life, and regulation of behavior, and reduced psychopathology and emotional reactivity [47]. Strong evidence for the effectiveness of mindfulness in reducing depression, anxiety, and stress in adults exists [50‐53]. Moreover, preliminary evidence from mindfulness studies suggests a reduction in physical complaints, such as (chronic) pain and somatization disorders [51, 54‐56]. Gu, Strauss, Bond, and Cavanagh [57] conducted a meta-analytic review about which mechanisms of change underlie improved mental health and wellbeing in adults who followed a mindfulness based intervention. Results evidence that the effects of mindfulness based interventions indirectly improved mental health (e.g. depression, stress, anxiety, mood states, and negative affect) through changes in cognitive and emotional reactivity, mindfulness, and repetitive negative thinking. Preliminary but insufficient evidence was found for self-compassion and psychological flexibility as mechanisms of change. However, another study did find evidence that self-compassion is a mediating mechanism in MBCT’s treatment outcomes [58].

Although the effects of mindfulness training in adults are well established, research on the effectiveness of mindfulness training in child and adolescent psychiatry is a relatively new domain. The majority of research in this field addresses children and adolescents in non-clinical samples [46]. The meta-analysis conducted by Zoogman et al. [46] included 20 studies on mindfulness based interventions with youth, of which four were clinical studies. Results show a small to moderate universal effect size for all mindfulness interventions taken together (del = 0.23), surpassing the effects of active control groups. Moreover, findings suggest that mindfulness training may be more beneficial for clinical samples than for non-clinical samples, and also more effective in reducing symptoms of psychopathology than other outcome measures. These studies show preliminary evidence that mindfulness based interventions are also beneficial for youth with a variety of psychological symptoms, as improvements were reported on measures of attention, internalizing and externalizing behavior problems, sleep, anxiety, and academic performance.

Regarding studies that specifically focused on the effects of mindfulness training for children and adolescents with ADHD (and their parents), so far, 8 studies have been performed.

The study of Bögels et al. [59] included 14 clinically referred adolescents (aged 11 to 18) suffering from externalizing disorders and their parents, of which two adolescents had a primary ADHD diagnosis and another two had co-morbid ADHD. The adolescents followed an early version of the 8-week MYmind mindfulness training with a parallel mindful parenting training for their parents (Bögels SM. MYmind: a mindfulness training for children with ADHD and their parents. In preperation). Adolescents and their parents were measured at waitlist, pre-test, post-test, and at 8-week follow-up. After the training, adolescents reported a substantial improvement on personal goals, internalizing, externalizing, and attention problems, happiness, and mindful awareness, and scored substantially higher on the d2 Test of Attention. In turn parents reported at post-test an improvement in their adolescents goals, externalizing and attention problems, self-control, attunement to others, and withdrawal. These effects were maintained at 8-week follow-up.

In the study of Singh et al. [60], two children with ADHD (aged 10 and 12) and their mothers participated. Children received a 12-session mindfulness training parallel to the mindful parenting training of their mothers, using a multiple baseline across mothers and children design. Mothers reported an improvement in compliance by their child as a result of the mindful parenting training, compliance was further increased by the child training. Results were maintained during the 24-week follow-up. Moreover, their results evidenced an improved mother-child interaction and satisfaction with their parenting. Children in this study were only assessed on a behavioral outcome, but not on core symptoms of ADHD.

Zylowska et al. [61] conducted a feasibility study with a pre- and post-test design, with 24 adults and 8 adolescents with ADHD, who followed an 8-week mindfulness training adapted for ADHD. After the training participants reported a decline in self-reported ADHD symptoms, but not hyperactivity, and improvements on neurocognitive tasks for measures of attentional conflict, but not working memory. In adults improvements were found in anxiety and depression. Due to the low numbers in this study no separate conclusions were drawn for adolescents alone.

In a study of Haydicky et al. [62] effects of a 20-week Mindfulness Martial Arts training were evaluated in 60 children in a clinical sample of adolescent boys (aged 12-18) with learning disabilities, using a pre-and post-test design and a waitlist control group. Twenty-eight participants were diagnosed with co-occurring ADHD of which 14 were assigned to the mindfulness training and 14 to the waitlist control group. Findings in this subgroup showed a decrease in parent-rated externalizing behavior, oppositional defiant problems, and conduct problems. In another study of Haydicky et al. [63] effects of the 8-week MYmind mindfulness training, for adolescents with ADHD (n = 18, aged 13-18) and a parallel mindful parenting training for their parents (n = 17), were evaluated using a pre-post-follow-up design and a within-group waitlist control without randomization. At post-test adolescents did not report improvements on any of the measures. However, parents reported a decline in their adolescents’ inattention, conduct problems, and peer relationship problems and in their own parenting stress. Parents also reported an increase in their mindful parenting. Generally, gains achieved during the training were maintained at the 6-week follow-up and adolescents now reported a decrease in their own internalizing problems.

Another study measured the effects of the MYmind mindfulness training for 13-18 year old adolescents with ADHD (n = 9) and a parallel mindful parenting training for their parents (n = 13), using a time-series design during baseline, the training, and six months follow-up [64]. Results showed a decline in parent and adolescent stress, and parent and adolescent distress due to family conflict. Parents, but not adolescents, reported a reduction in adolescents’ inattention, hyperactivity, and impulsivity. These improvements were generally maintained at follow-up six months later.

Finally, two studies were conducted by Bögels and colleagues. The first study [65] assessed the effects of an early version of the 8-week MYmind mindfulness training for children with ADHD (n = 22, aged 8-12) with parallel mindful parenting training, using a pre-post-follow-up design and a within-group waitlist control without randomization [65]. Results showed a significant reduction of parent-rated ADHD behavior of themselves and their child, which was maintained at follow-up. Furthermore, a significant reduction of parental stress and over-reactivity at follow-up was shown. The second study assessed the effects of an early version of the MYmind mindfulness training for adolescents with ADHD (n = 10, aged 11–15) with parallel mindful parenting training, using a pre-post-follow-up design without randomization [66]. Findings showed a reduction of self-reported ADHD behavior in adolescents and improvements on objective neuropsychological computerized tasks of attention. Based on fathers’ and teachers’ reports a decline in ADHD behavior in adolescents was shown. Fathers reported reduced parenting stress as a result of the mindful parenting training and mothers reported a decline in parental over-reactivity. At 8-week follow-up the effects were even stronger than at the post-test, however, the effects waned off at 16-weeks follow-up.

In sum, preliminary effectiveness of mindfulness training for children and adolescents with ADHD is clearly demonstrated in the above-mentioned studies. However, the current stage of research in this field is limited by a lack of randomized and controlled (clinical) trials with large samples, standardized formats for interventions, objective measures, and that are generalizable outside the intervention context [46, 67]. Therefore, it is a logical step to further assess the (cost-) effectiveness of mindfulness training, in children and adolescents with ADHD, in a well-designed RCT with a large number of participants, in which mindfulness training is evaluated against methylphenidate, the current treatment of choice for childhood ADHD.