In my thesis I conclude the following:

When you read the literature about ADHD, it seems that patients are impaired in several cognitive domains, and that these impairments are associated with aberrant brain structure and function. In this thesis, I have shown that this image is an oversimplification. Instead, ADHD in adulthood is an overarching label that includes various cognitive and possibly neurobiological profiles. Many different pathways can result in the symptoms required for an ADHD diagnosis, but using only this diagnostic label will not help us in understanding the aetiological pathways. The best way forward may therefore be to approach the disorder as a network of interconnected characteristics and to investigate the biological pathways of each of these behavioural characteristics, beyond the boundaries of a single psychiatric disorder.