In the first several decades of ADHD treatment research, there was little focus on developmental level. For example, in the series of four evidence-based treatment reviews for youth with ADHD that began in 1998 (Evans, Owens, & Bunford, 2014; Pelham & Fabiano, 2008; Pelham et al., 1998), it was not until the most recent version that levels of evidence were differentiated based on ages of participants (Evans et al., 2018). Indeed, all of the issues addressed previously in the discussion of mechanisms of change are not static, as mechanisms are likely to change across development. Thus, it is critical to identify relevant mechanisms at each stage of development. However, even if the mechanism remains the same across development, treatment outcomes may also differ as a function of development. For example, one developmental issue is that effect sizes of behavioral interventions may diminish as children age into adolescence (Sanders, Kirby, Tellegen, & Day, 2014). Although it is unlikely that behavioral principles become less relevant as children age, it is possible that the ability of an adult to adequately manage the complexities of reinforcement and punishment that operate in the life of a 15-year-old adolescent is far less than an adult’s ability to manage these in the life of a 5-year-old.



YOUTH EMPOWERMENT, EDUCATION
Training interventions
BY AAP Bridge at AAPBridge
The complex web of contingencies in the environment of adolescents means that parents and teachers are competing with numerous other sources of reinforcement and punishment (e.g., peer attention, social reputation issues, variety of achievement goals). Understanding not only the behavioral mechanisms of action, but also those associated with cognitive and training interventions across development are likely to lead the field to new and innovative approaches to treatment.
ADHD is a chronic condition. A childhood diagnosis of ADHD places individuals at risk for deleterious outcomes in adulthood, regardless of their ADHD diagnostic status later in life (Hechtman et al., 2016). Furthermore, the Multimodal Treatment Study of ADHD (MTA) found that beneficial effects of behavioral and medication treatment for ADHD implemented during childhood were not maintained into adolescence and young adulthood (Molina et al., 2009). To address the chronic nature of ADHD, the need for sustained monitoring of outcomes over time, the changing presentation of the condition and associated risks over the course of development, and the need for intervention at various points during development (illustrated in the case of James), our team has espoused a life course model of care. This model is complementary with key elements of the chronic care model, which has been recommended as a framework for the management of ADHD