Evidence-based treatment refers to the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. A practitioner can know what the best current evidence is by making use of guidelines. However, the guidelines only demonstrate what type of treatment is recommended for specific disorders but do not necessarily provide information about the efficacy.

The effectiveness of a treatment refers to the extent to which a treatment achieves its intended effect in the usual clinical setting. Efficacy refers to the extent to which a treatment has the ability to bring about its intended effect in ideal circumstances (e.g. randomized clinical trial).

For every treatment protocol, there should be information on efficacy. This information can be obtained by reviewing the literature (e.g. RCT; meta-analyses). It can also be found in databases following certain criteria (e.g. APA). For the Dutch database, there are several levels of efficacy:

1. Well-reasoned
   This entails that there is a clear description of the treatment which makes effectiveness plausible.
2. First indications of effectiveness
   This entails that there are two studies using pre- to post measurements which yield positive results.
3. Good indications of effectiveness
   This entails that there are two studies using reasonable designs or one study with strong evidence using a randomized controlled trial with follow-up.
4. Strong indications of effectiveness
   This entails that there are two studies with strong evidence of effectiveness (e.g. RCT with follow-up).

Stimulant medication is the most used medication for ADHD. The short-lasting formula lasts for four hours and the long-lasting formula lasts for eight hours. Stimulant medication can be methylphenidate or dextroamphetamine. Atomoxetine is a different type of medication which reduces overactivity, impulsivity and inattention. It is supposed to improve associated behaviours (e.g. academic performance; social functioning).

Behavioural interventions are interventions aimed at changing behaviours. This is supposed to increase the desired behaviour and decrease the undesired behaviour. It consists of classic contingency management (1), behaviour therapy (2) and cognitive behaviour therapy (3).

A lot of the children with ADHD who have a combined treatment (i.e. behavioural treatment and pharmacological treatment) have normalized behaviour after 14 months. Medication appears to be highly effective but the doses can be lowered with behavioural treatment and the parents have a preference for behavioural therapy.

Medication has both advantages and disadvantages. Medication does not always improve aspects of functioning (e.g. academic achievement).

It appears as if people who can choose their own treatment have better outcome. Depending on age and symptom severity, behavioural intervention and medication are the recommended treatments.

The effect of medication and combined medication plus behavioural interventions had greater effects in the short term but the long-term effects of medication and behavioural intervention did not differ. The parents of a child with ADHD should always be informed about the potential advantages and disadvantages of ADHD medication.

Behavioural interventions are often designed for oppositional behaviour. These interventions tend to improve comorbid problems and other ADHD-related problems (e.g. social and organizational skills). Behavioural intervention appears to decrease negative parenting, increase positive parenting and decreased children’s comorbid conduct problems. Behavioural interventions also led to an improved parenting self-concept which has an empowering effect in the process of breaking negative parent-child interaction cycles.

There are also treatments that are not recommended for ADHD (e.g. CogMed; neurofeedback). There are also a lot of treatments that are not studied enough to draw conclusions about the effectiveness of the treatment of ADHD (e.g. mindfulness).

There is an overall positive effect of behavioural intervention on ADHD symptoms and behavioural problems. The most important techniques for the treatment effect were the number of sessions of psycho-education (maximum of 2) and individual versus group treatment. Individual treatment appears to be more effective than group treatment.

There is a lot of heterogeneity within ADHD. Therefore, it is unlikely that behavioural interventions work equally for all individuals. This increases the need for personalized treatment. There appears to be equal effectiveness of behavioural intervention across children’s age (1), IQ (2), sex (3), medication status (4) and comorbidity (5). Children who did not receive treatment had poorer outcomes than children who received any treatment.

More conduct disorder symptoms and single parenthood are associated with larger treatment effects. Furthermore, more ADHD symptoms at baseline (i.e. before treatment) are associated with more impairment.

ADHD symptoms tend to get worse for children with comorbid conduct disorder if they do not receive any treatment. When they receive treatment, their symptoms will mostly remain similar to baseline. Behavioural interventions appear to mostly have a protective rather than an ameliorative effect.

Girls appear to have less severe inattention, hyperactivity and impulsivity but greater intellectual impairment than boys with ADHD. Girls also tend to have more internalizing comorbid disorders than boys.

In adolescence, there is less parental control and more independence. Furthermore, there is a greater influence of peers. This increases the demands on executive functioning (1), motivation (2) and timing (3). For adolescents with ADHD, this could then lead to problems in school (1), with friends (2), with parents (3) and to comorbidity (4). Adolescence is accompanied by more distraction for adolescents with ADHD.

For adolescents, the treatments aimed at parents are less effective than in childhood. The school-based treatments are very intensive but show positive results. A lot of adolescents drop out of treatment before the treatment concludes. ADHD is one of the most important predictors for treatment drop-out. CBT/skills training aimed at the adolescent, parent or teacher training or medication is recommended for the treatment of ADHD in adolescents.

The plan my life treatment (PML) consists of 8 sessions for the adolescent and 2 parental sessions. Motivational interviewing is used throughout the treatment. The strategies to cope with ADHD symptoms are introduced as an experiment and the adolescent can determine whether he wants to use these strategies. It concludes with a rating of the therapist and the session. It focuses on planning of school and homework (1), planning in general (2) and how to ask for help from family and friends (3). The solution-focused treatment (SFT) is a treatment focused on solutions and not necessarily on improving planning and planning-related skills.

Qualitative subgroup interactions refer to the idea that there are different subgroups in the data that may perform better on a certain treatment (e.g. males perform better in one treatment than females while females outperform males in another group). Quantitative subgroup interactions refer to the phenomenon where optimal treatment is the same in all subgroups but the size of the between-treatment difference differs across subgroups (e.g. effect is larger for males than for females). Quantitative subgroup interactions imply that patient characteristics defining the subgroups are moderators. QUINT looks for subgroups in the data based on reasonable predictors (e.g. sex). The presence of subgroups indicates the need for personalized treatment.

Adolescents with fewer ADHD symptoms should receive SFT over PML. People with more depressive symptoms at the start of the treatment gained more from SFT than PML with regard to planning problems. For people who scored low on depression and higher on anxiety, the CBT with planning treatment is more effective. However, this does not necessarily indicate a need for personalized treatment.

Only the results for PML were upheld in the long-term. The positive effects of SFT on less severe cases of ADHD and the positive effects of PML for more severe cases of ADHD did not remain in the long-term. It is possible that the PML and SFT treatments follow different trajectories to a comparable endpoint.

Anxiety in ADHD is associated with negative affectivity and disruptive behaviour rather than fearfulness. This implies that some ADHD symptoms could be the result of anxiety and vice versa. Anxiety experienced by adolescents may be attributed to poorer executive functions.

Every new life phase increases the risk of academic problems and the development of comorbidities. There is a lack of treatment for adolescents and students with ADHD. The plan my life treatment is effective in high school but seems less effective in university.

A lot of adolescents with ADHD (72%) have sleeping problems. This appears to worsen symptoms. This implies the potential effectiveness of a sleep intervention in adolescents.