Boyer et al. (2016). Qualitative treatment-subgroup interactions in a randomized clinical trial of treatments for adolescents with ADHD: Exploring what cognitive-behavioural treatment works for whom.” – Article summary

Girls with ADHD appear to have less severe inattention, hyperactivity and impulsivity but greater intellectual impairments than boys with ADHD. Girls also tend to have more internalizing comorbid disorders than boys whilst boys with ADHD are at higher risk for externalizing psychiatric comorbidities than girls. The heterogeneity of ADHD increases the need for personalized treatment.

Plan my life (PML) is a treatment for ADHD which is focused on improving planning and planning-related skills. Solution-focused treatment (SFT) is a treatment focused on solutions and not necessarily focused on improving planning and planning-related skills. SFT is focused on finding solutions for chosen problems. Both treatments appear to be effective, although PML shows more reduction of parent-rated planning problems and higher treatment satisfaction of parents and therapists.

Qualitative treatment-subgroup interaction refers to the phenomenon where the optimal treatment for one subgroup differs from that for another subgroup. Quantitative treatment-subgroup interaction refers 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). This implies that the patient characteristics defining the subgroup are moderators of treatment effect.

Having no or a single comorbid disorder (1), being older of age (2), having a mother with high parenting self-efficacy (3) or not having a particular gene (4) positively influence the effects of behavioural treatment on ADHD symptoms.

There appears to be no need for personalized treatment allocation for adolescents with ADHD symptoms in the treatment of ADHD symptoms. Adolescents with less ADHD symptoms should receive SFT over PML. On the other hand, greater treatment gains were obtained for adolescents with more severe ADHD symptoms who were assigned to the PML group.

There also appears to be no need for personalized treatment allocation for adolescents with ADHD symptoms when it comes to planning problems. Adolescents with more depressive symptoms at the start of treatment gained more from SFT than from PML with regard to planning problems. However, for adolescents with more anxiety symptoms and less depressive symptoms, there was more improvement on planning problems in PML than in SFT. There was no difference for adolescents with ADHD who scored low on both anxiety and depressive symptoms.

Only the results of the PML were upheld in the long-term. This implies that adolescents with more anxiety symptoms and less depressive symptoms should use PML rather than SFT, especially when it comes to planning problems. The more positive effects of PML for more severe cases of ADHD and more positive effects of SFT on less severe cases of ADHD did not remain in the long-term.

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

It is possible that the two different treatments (i.e. PML and SFT) follow different trajectories to a comparable endpoint.